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Trade-offs in Medical LLM Adaptation: An Empirical Study in French QA
Ikram Belmadani, Oumaima El Khettari, Carlos Ramisch, Frederic Bechet, Richard Dufour, Benoit Favre
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Status: succeeded | Model: Gemma-4-26B-A4B | Prompt: intel-v1 | Confidence: 99%
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Summary
This study investigates the effectiveness of different domain adaptation strategiesâContinual Pretraining (CPT), Supervised Fine-Tuning (SFT), and their combination (CPT+SFT)âfor medical Large Language Models (LLMs) using French medical question-answering (QA) as a case study. The researchers evaluated three model families (Gemma-4B, Mistral-7B, and Llama-7B/13B) across three initialization types (General, Instruct, and Medical). The results indicate that while CPT+SFT often achieves the highest scores in Multiple-Choice QA (MCQA), the gains over SFT alone are frequently small and not always statistically significant, making SFT a more cost-effective default. For Open-Ended QA (OEQA), CPT improves overlap-based metrics, but SFT can sometimes degrade generation quality. The study also demonstrates effective cross-lingual transfer from French adaptation to English benchmarks.
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Gemma-4B â evaluatedwith â CPT
confidence 100% · We compare CPT, SFT, and their combination across three model families...
Mistral-7B â evaluatedwith â SFT
confidence 100% · We compare CPT, SFT, and their combination across three model families...
DoRA â implementedin â SFT
confidence 100% · We employ DoRA (Weight-Decomposed Low-Rank Adaptation)... SFT relies on parameter-efficient adaptation.
MedInjection-FR â usedfor â SFT
confidence 100% · We use the train and validation sets of the MedInjection-FR corpus... for SFT.
NACHOS corpus â usedfor â CPT
confidence 100% · CPT. We use NACHOS corpus (Labrak et al., 2023)...
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Abstract
Abstract:The development of large language models (LLMs) has led to an increased focus on their adaptation to specialized domains and languages, yet the effectiveness of domain adaptation strategies remains unclear. We present a study of medical domain adaptation using French medical question-answering (QA) as a case study. We compare continual pretraining (CPT), supervised fine-tuning (SFT), and their combination across three model families, multiple sizes, and three initialization types, explicitly disentangling adaptation effects from base model choice. We evaluate both multiple-choice (MCQA) and open-ended QA (OEQA) under greedy and constrained decoding using automatic metrics and LLM-as-a-Judge evaluation. For MCQA, CPT+SFT most often achieves the best scores, but gains over SFT are small and frequently not statistically significant, making SFT a strong and cost-effective default. For OEQA, CPT consistently improves overlap-based metrics, while SFT often degrades generation quality; instruction tuning and CPT+SFT are preferred by LLM-based evaluation. Cross-lingual experiments further show effective transfer from French adaptation to English benchmarks. Overall, we provide practical guidelines for selecting adaptation strategies under computational constraints.
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- Source: https://arxiv.org/abs/2606.19266v1
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Trade-offs in Medical LLM Adaptation: An Empirical Study in French QA Ikram Belmadani1,2 Oumaima El Khettari2 Carlos Ramisch1 Frederic Bechet1 Richard Dufour2 Benoit Favre1,3 1Aix-Marseille Univ., CNRS, LIS UMR 7020, 13000 Marseille, France, 2Nantes Univ., Ăcole Centrale Nantes, CNRS, LS2N UMR 6004, 44000 Nantes, France, 3Grenoble Alpes Univ., CNRS, INRIA, Grenoble INP, LIG UMR 5217, 38000 Grenoble, France Correspondence: first.last@univ-amu.fr, univ-nantes.fr Abstract The development of large language models (LLMs) has led to an increased focus on their adaptation to specialized domains and languages, yet the effectiveness of domain adaptation strategies remains unclear. We present a study of medical domain adaptation using French medical question-answering (QA) as a case study. We compare continual pretraining (CPT), supervised fine-tuning (SFT), and their combination across three model families, multiple sizes, and three initialization types, explicitly disentangling adaptation effects from base model choice. We evaluate both multiple-choice (MCQA) and open-ended QA (OEQA) under greedy and constrained decoding using automatic metrics and LLM-as-a-Judge evaluation. For MCQA, CPT+SFT most often achieves the best scores, but gains over SFT are small and frequently not statistically significant, making SFT a strong and cost-effective default. For OEQA, CPT consistently improves overlap-based metrics, while SFT often degrades generation quality; instruction tuning and CPT+SFT are preferred by LLM-based evaluation. Cross-lingual experiments further show effective transfer from French adaptation to English benchmarks. Overall, we provide practical guidelines for selecting adaptation strategies under computational constraints. Trade-offs in Medical LLM Adaptation: An Empirical Study in French QA Ikram Belmadani1,2 Oumaima El Khettari2 Carlos Ramisch1 Frederic Bechet1 Richard Dufour2 Benoit Favre1,3 1Aix-Marseille Univ., CNRS, LIS UMR 7020, 13000 Marseille, France, 2Nantes Univ., Ăcole Centrale Nantes, CNRS, LS2N UMR 6004, 44000 Nantes, France, 3Grenoble Alpes Univ., CNRS, INRIA, Grenoble INP, LIG UMR 5217, 38000 Grenoble, France Correspondence: first.last@univ-amu.fr, univ-nantes.fr Figure 1: Overview of the experimental pipeline for evaluating medical domain adaptation strategies. 1 Introduction LLMs are increasingly applied to medical question-answering (QA) and clinical reasoning, where accuracy, robustness, and domain-specific knowledge are critical (Huang et al., 2024). However, most high-performing LLMs are trained on general-domain data, making domain adaptation essential for safe medical deployment. In practice, this adaptation relies on continual pretraining (CPT) on domain corpora and supervised fine-tuning (SFT) on task-specific data. Despite their widespread use, the relative effectiveness of these strategies remains unclear. Their impact depends on training scale, data composition, and optimization choices (Christophe et al., 2024; Lu et al., 2025), and even combined approaches yield inconsistent or statistically insignificant gains (Jeong et al., 2024a). Most prior work fixes base model initialization, making it difficult to disentangle adaptation effects (Lu et al., 2025; Christophe et al., 2024). Evaluations are also predominantly English-centric, and largely focus on MCQA, limiting interpretation and generalization, especially given recent evidence of memorization in medical LLMs (Li et al., 2025). More broadly, this work is motivated by a practical constraint often overlooked in the literature. In many real-world settings, especially for non-English medical NLP, both domain-specific data and computational resources are limited. As a result, the key question is not whether one strategy can theoretically outperform another, but how to allocate limited resources effectively. In this context, practitioners face a concrete and unresolved question: given limited data and computational resources, which adaptation strategy should be prioritized? Existing studies provide partial answers, but heterogeneous setups make it difficult to derive actionable guidelines. To address these limitations, we conduct a controlled study of medical domain adaptation using French medical QA as a case study. We compare CPT, SFT, and their combination across model families and sizes while varying base initialization, and evaluate models in both French and English to isolate domain and cross-lingual effects. We include OEQA as a complementary evaluation of generative behavior, but note that its assessment remains challenging; our conclusions are therefore primarily grounded in MCQA. Our goal is to provide practical guidance on when and why CPT and SFT are effective under realistic constraints. Our study is guided by the following research questions: âą RQ1: What are the performance and efficiency trade-offs between CPT and SFT across model families and sizes? âą RQ2: How does base model initialization influence the effectiveness of CPT and SFT for medical domain adaptation? âą RQ3: How does French medical adaptation affect cross-lingual transfer to English? Our contributions are: (i) we introduce a controlled and reproducible framework to compare medical domain adaptation strategies across model families, sizes, initialization types, and decoding settings; (i) we provide a statistically grounded analysis of CPT and SFT for medical QA, covering performance trade-offs, error patterns, and cross-lingual transfer to English benchmarks. All resources are publicly available: https://github.com/ikram28/MedAdapt. 2 Related Work Medical LLM adaptation primarily relies on CPT on domain-specific corpora and SFT on instructionâresponse data, both shown to support domain transfer (Gururangan et al., 2020; Gema et al., 2024). CPT has been adopted in models such as MediTron (Chen et al., 2023b), BioMistral (Labrak et al., 2024a), PMC-Llama (Wu et al., 2023), and MedGemma (Sellergren et al., 2025). However, recent analyses question the robustness and consistency of CPT gains under stricter evaluation protocols (Jeong et al., 2024a). In parallel, SFT-based models such as ChatDoctor (Li et al., 2023) and MedAlpaca (Han et al., 2023) report great task-level improvements, though evaluations remain largely in English. Medical domain adaptation is further challenged in non-English settings due to limited domain-specific resources. Several multilingual medical LLMs have been proposed, including Medical mT5 (GarcĂa-Ferrero et al., 2024), BiMediX (Pieri et al., 2024), Apollo (Wang et al., 2024a), and MMedLM (Qiu et al., 2024). However, these models are mostly evaluated on translated benchmarks, with limited validation on native-language medical tasks, leaving their language- and cultural-specificities underexplored. Evaluation practices also pose challenges. Widely used benchmarks such as PubMedQA (Jin et al., 2019), MedQA (Jin et al., 2019), and MedMCQA (Pal et al., 2022) primarily target English. Beyond proposing individual models, recent work has compared adaptation strategies in controlled settings. Christophe et al. (2024) analyze CPT, SFT, and related techniques for clinical LLMs, finding that CPT alone yields limited gains but can amplify performance when combined with instruction tuning. Similarly, Lu et al. (2025) study CPT, SFT, and preference-based optimization across domains, highlighting complex interactions between adaptation methods. However, these studies focus on English and fix the base model initialization. In contrast, in this work, we systematically compare CPT, SFT, and their combination across multiple model families and initialization points for French medical QA, while also evaluating cross-lingual performance and analyzing adaptation behavior. 3 Experimental Framework We propose a controlled experimental framework to evaluate medical domain adaptation strategies across architectures, initialization points, and task formats, as illustrated in Figure 1. Our setup explicitly varies (i) the base model and its prior training, (i) the adaptation strategy, and (i) the evaluation task and language in order to isolate the factors that drive adaptation effectiveness. 3.1 Base Models and Adaptation Approaches Our study focuses on model families with three complementary initialization states: (i) a general-purpose base model, (i) an instruction-tuned variant, and (i) a medically adapted version obtained via CPT. This constraint is central to our experimental design, as it enables a controlled comparison that isolates the effect of adaptation strategy from that of the starting point. As a result, model selection is restricted to families providing these aligned variants, rather than to the most recent model releases. We consider three model families spanning different sizes, pretraining regimes, and linguistic exposure. Specifically, we include Mistral-7B, Gemma-4B, and Llama models at the 7B and 13B scales. For Mistral-7B, we use Mistral-7B-v0.1 and its instruction-tuned version, and BioMistral-7B, a model adapted to the biomedical domain via CPT (Jiang et al., 2023; Labrak et al., 2024b). For Gemma, we rely on the Gemma-3-4B pretrained and instruction-tuned models, together with MedGemma-3-4B, which incorporates medical pretraining (Team et al., 2025; Sellergren et al., 2025). Finally, for Llama, we include both 7B and 13B variants, using the base and chat versions of Llama-2, as well as their medically adapted counterparts, MediTron-7B and MedLlama-13B (Touvron et al., 2023; Chen et al., 2023a; Wu et al., 2024). These families differ not only in scale but also in pretraining data and exposure to French. Mistral and Gemma are explicitly multilingual, whereas Llama models are primarily English-centric, although exact language proportions are not disclosed. Except for MedGemma, whose medical pretraining corpus is not fully documented, all medical variants rely on PubMed Central as their primary biomedical source111https://pmc.ncbi.nlm.nih.gov/. Across all model families and initialization points, we investigate three adaptation strategies: (i) CPT on domain-specific corpora, (i) SFT on instruction-response pairs, and (i) a sequential CPT+SFT pipeline. 3.2 Training Data CPT. We use NACHOS corpus (Labrak et al., 2023), an open-source French medical dataset comprising 4 GB of text collected from French medical websites; full details are provided in Appendix A. SFT. We use the train and validation sets of the MedInjection-FR corpus (Belmadani et al., 2026b), which contains 543 505 instruction-response pairs. The dataset includes multiple-choice questions with a single unique correct answer (MCQU, ⌠83%), multiple correct answers (MCQ, ⌠6%), and OEQAs (⌠11%). This mixture allows us to evaluate adaptation effects across both discriminative and generative medical reasoning tasks. Additional dataset details are provided in Appendix B. 3.3 Training Process To explore the trade-off between computational cost and model plasticity, we adopt contrasting fine-tuning regimes for CPT and SFT. CPT is performed using full-parameter fine-tuning, while SFT relies on parameter-efficient adaptation. This choice is supported by preliminary experiments, as explained in Appendix E. CPT. CPT is performed for three epochs following the setup of Labrak et al. (2024b). Full hyperparameter details are provided in Appendix C. SFT. We employ DoRA (Weight-Decomposed Low-Rank Adaptation) (Mao et al., 2024), an extension of LoRA (Hu et al., 2022) that decouples magnitude and directional updates. We select DoRA after preliminary experiments, as detailed in Appendix E. SFT is run for ten epochs, with hyperparameters reported in Appendix D. 3.4 Evaluation Protocol Benchmarks. We evaluate all models on MedInjection-FR test set, which consists of 14 533 native French medical examples and 13 293 translated examples derived from established English benchmarks. The test set covers MCQU, MCQ, and OEQA tasks, enabling evaluation of both answer selection and free-form answers. Benchmark sources and translation procedure are detailed in Appendix G. Prompting Strategy. All evaluations are conducted in a zero-shot setting using greedy, deterministic decoding to ensure reproducibility. For MCQU and MCQ tasks, following Liang et al. (2022); Beeching et al. (2023); Chen et al. (2023a), we restrict the output vocabulary to valid answer options to prevent hallucinated responses. To mitigate position bias, we randomly shuffle answer choices three times and report aggregated results, following best practices for MCQ evaluation (Pezeshkpour and Hruschka, 2024). Prompt templates are provided in Appendix H. Evaluation Metrics. For MCQU, we report Exact Match (EM), which measures the proportion of questions for which the predicted answer exactly matches the gold answer. For MCQ, we additionally report the Hamming score, which accounts for partial overlap between predicted and reference answer sets and is therefore more informative for multi-answer questions. Formal definitions of both metrics are provided in Appendix F. For OEQA, we rely on both automatic text-based metrics and model-based judgments. We report BLEU (Papineni et al., 2002), ROUGE (Lin, 2004), METEOR (Banerjee and Lavie, 2005), and BERTScore (Zhang et al., 2019) as automatic baselines. Their reliability was assessed through agreement with senior physician annotations on a held-out subset of 500 OEQA instances in Belmadani et al. (2026a), where MedGemma-27B was identified as the most stable and best-performing LLM judge, and is therefore used in the present work. Statistical Significance and Error Analysis. We assess statistical significance using a percentile bootstrap procedure with 10 000 resamples, following Jeong et al. (2024b). Differences between paired model configurations are considered significant when the associated two-sided p-value is below a predefined threshold α. To control for multiple comparisons, we apply the Bonferroni correction, yielding a corrected α as specified in Appendix J. In addition, we conduct an error analysis by examining output probabilities, confidence scores, and entropy, enabling us to characterize how CPT and SFT affect uncertainty and error patterns across different base model initializations. 4 Results and Discussion Model Type Strategy MCQ MCQU Aggregation OEQA EM Hamming EM EM ROUGE-L BERT-F1 Judge [HTML]CFE2F3Gemma-4B GENERAL Base 2.242.24 30.1730.17 27.1127.11 14.6814.68 7.117.11 46.6246.62 25.0925.09 CPT 0.730.73 11.7111.71 25.8325.83 13.2813.28 10.18 49.07 25.71 SFT 3.733.73 43.57 32.3632.36 18.0518.05 8.238.23 47.7647.76 21.6021.60 CPT+SFT 3.90 42.8142.81 32.59 18.25 6.016.01 45.7845.78 24.8024.80 INSTRUCT Base 4.83 44.0144.01 29.3029.30 17.0617.06 7.38 48.94 47.71 CPT 3.473.47 46.0046.00 25.0525.05 14.2614.26 4.574.57 42.7742.77 13.3513.35 SFT 3.683.68 48.22 31.95 17.81 2.202.20 38.2638.26 20.2120.21 CPT+SFT 3.423.42 48.1448.14 30.7330.73 17.0717.07 3.123.12 40.9040.90 20.7620.76 MEDICAL Base 1.981.98 31.4631.46 26.4126.41 14.1914.19 7.38 48.94 22.01 CPT 1.681.68 24.0424.04 25.1325.13 13.4113.41 6.776.77 45.1845.18 1.951.95 SFT 3.54 46.22 30.6630.66 17.1017.10 5.705.70 45.6645.66 14.2314.23 CPT+SFT 3.383.38 43.2843.28 30.86 17.12 5.045.04 43.0543.05 11.4111.41 [HTML]CFE2F3Mistral-7B GENERAL Base 0.370.37 5.405.40 28.5228.52 14.4414.44 5.825.82 44.2144.21 27.23 CPT 3.543.54 30.5030.50 27.2127.21 15.3715.37 7.227.22 46.3246.32 24.5724.57 SFT 5.245.24 21.6221.62 32.88 19.0619.06 8.83 48.02 22.9322.93 CPT+SFT 6.13 30.86 32.2932.29 19.21 6.626.62 46.3546.35 24.8924.89 INSTRUCT Base 4.864.86 23.5323.53 24.9224.92 14.8914.89 7.347.34 49.6649.66 30.1430.14 CPT 7.32 36.18 28.7928.79 18.0618.06 13.51 53.87 37.59 SFT 6.806.80 23.4223.42 31.61 19.21 12.4112.41 52.7252.72 17.6317.63 CPT+SFT 5.455.45 32.4732.47 30.0930.09 17.7717.77 9.029.02 48.9948.99 32.1332.13 MEDICAL Base 2.802.80 17.4717.47 26.6926.69 14.7414.74 11.3411.34 51.58 20.7620.76 CPT 3.573.57 24.4324.43 25.7325.73 14.6514.65 12.41 51.4551.45 17.8917.89 SFT 3.363.36 26.3726.37 31.6231.62 17.4917.49 8.758.75 47.8647.86 16.7216.72 CPT+SFT 4.94 27.27 32.58 18.76 9.159.15 48.6348.63 24.96 [HTML]CFE2F3Llama-7B GENERAL Base 1.331.33 12.0112.01 25.7225.72 13.5313.53 5.055.05 41.2741.27 9.399.39 CPT 1.121.12 12.8612.86 25.5925.59 13.3613.36 10.58 47.85 3.783.78 SFT 2.662.66 28.4128.41 28.9328.93 15.8015.80 6.026.02 44.4944.49 7.677.67 CPT+SFT 3.17 46.00 29.89 16.53 5.855.85 44.6744.67 12.26 INSTRUCT Base 3.953.95 34.4334.43 25.0825.08 14.5114.51 2.572.57 43.8543.85 25.3525.35 CPT 3.933.93 42.67 25.0725.07 14.5014.50 11.1611.16 51.37 26.0626.06 SFT 5.12 21.0621.06 29.32 17.22 11.44 51.2851.28 12.9212.92 CPT+SFT 3.133.13 25.9825.98 25.0725.07 14.1014.10 9.929.92 50.9950.99 27.84 MEDICAL Base 0.230.23 2.902.90 24.4324.43 12.3312.33 5.615.61 43.2543.25 12.5012.50 CPT 2.372.37 28.0628.06 25.6025.60 13.9913.99 8.00 45.79 13.1413.14 SFT 3.243.24 29.1029.10 30.4430.44 16.8416.84 5.405.40 42.2542.25 9.509.50 CPT+SFT 3.80 44.95 31.52 17.66 5.875.87 44.3444.34 17.39 [HTML]CFE2F3Llama-13B GENERAL Base 2.142.14 21.2021.20 26.1126.11 14.1314.13 2.102.10 33.2533.25 11.7911.79 CPT 2.532.53 19.1719.17 26.9926.99 14.7614.76 14.12 50.36 5.665.66 SFT 3.54 40.49 30.9530.95 17.2417.24 5.605.60 43.1943.19 14.8814.88 CPT+SFT 3.343.34 29.5929.59 32.36 17.85 6.306.30 45.4545.45 20.38 INSTRUCT Base 0.090.09 29.7429.74 21.5221.52 10.8110.81 3.403.40 45.3145.31 30.0230.02 CPT 5.635.63 37.40 25.0125.01 15.3215.32 12.3412.34 53.07 36.19 SFT 6.586.58 23.9623.96 30.2030.20 18.3918.39 11.5411.54 50.9450.94 11.8111.81 CPT+SFT 7.77 25.2625.26 31.58 19.68 12.86 52.4652.46 20.2220.22 MEDICAL Base 1.771.77 11.8211.82 24.6224.62 13.1913.19 5.005.00 42.1142.11 10.8610.86 CPT 2.262.26 30.8730.87 24.1024.10 13.1813.18 8.008.00 45.7945.79 13.3913.39 SFT 3.123.12 41.2441.24 30.6230.62 16.8716.87 6.856.85 45.2245.22 13.7713.77 CPT+SFT 3.24 45.59 32.25 17.74 8.38 46.29 19.55 Table 1: Constrained decoding results (%) for MCQ/MCQU and OEQA. Aggregation corresponds to average EM over MCQ and MCQU. Bold denotes the best strategy, and underlining the best initialization. 4.1 MCQA Evaluation Table 1 reports performance on MCQA across three model families (Gemma-4B, Mistral-7B, Llama-7B-13B), three initialization types (General, Instruct, Medical), and three adaptation strategies (CPT, SFT, CPT+SFT). Results are shown for both MCQs and MCQUs, using EM and Hamming scores for MCQs. All results reported in this table are obtained using constrained decoding. The corresponding results under greedy decoding are provided in Appendix I. Effectiveness of Adaptation Strategy: A recurring pattern observed throughout the results is: BaseâȘCPT <SFT âČCPT+SFT Base [rgb]0,0,1 [named]pgfstrokecolorrgb0,0,1CPT < [rgb]0,0.6,0 [named]pgfstrokecolorrgb0,0.6,0SFT [rgb]1,0,0 [named]pgfstrokecolorrgb1,0,0CPT+SFT The strongest performance is most frequently achieved by the CPT+SFT adaptation. Across model families and initialization types, CPT+SFT yields the highest scores in aggregated EM as well as in MCQ and MCQU EM more often than any other strategy. However, a closer inspection of the results indicates that the gains brought by CPT+SFT over SFT alone are generally limited. When CPT+SFT attains the highest score, the margin over SFT rarely exceeds 1.3 points. In contrast, in configurations where SFT outperforms CPT+SFT, the performance gap is larger. For example, on Llama-7B Instruct, SFT exceeds CPT+SFT by 3.12 points, and a similar pattern is observed for Mistral-7B Instruct, with a gap of 1.44 points in favor of SFT. Furthermore, the statistical analysis reported in Appendix J shows that, when comparing each adapted model to its corresponding base model, the observed improvements are not always statistically significant. In particular, for Gemma Instruct, neither SFT nor CPT+SFT yields statistically significant gains over the base model. Likewise, for Llama-7B Instruct, the improvement brought by CPT+SFT is not statistically significant. These constitute the only cases in which the improvements of SFT or CPT+SFT over the base model fail to reach statistical significance. Consequently, although CPT+SFT most frequently ranks first, its advantage over SFT is not consistently substantial. By contrast, CPT alone exhibits less stable behavior. Although it can improve performance in some rare cases, it can also occasionally degrade performance compared to the base model. Moreover, it is the strategy that most often fails to produce statistically significant improvements over the base. This is the case for 8 models: MedGemma, all Llama-13B variants, Llama-7B GENERAL and INSTRUCT, and Mistral-7B GENERAL and MEDICAL. This suggests that representation-level domain adaptation is most effective when paired with task-specific supervision. Overall, while CPT+SFT ranks first most often, its limited and inconsistent gains over SFT, together with a substantially higher computational cost (see Appendix O), make SFT a strong default for medical MCQA. For example, on 7B models, CPT+SFT costs over $1 500 versus $360 for SFT, with a fourfold increase in carbon emissions. Impact of Model Initialization: The impact of model initialization (General / Instruct / Medical) varies across MCQA metrics and question formats. Considering the overall best scores across all model families, instruction-tuned models dominate the most demanding EM settings: the highest MCQ EM and aggregated MCQA EM scores are both achieved by Llama-13B Instruct, while the best MCQ Hamming score is obtained by Gemma-4B Instruct. In contrast, the best MCQU EM score is achieved by a general Mistral model. At the family level, the patterns differ. For MCQ EM, the best score within each model family is always obtained by an instruction-tuned variant, confirming that instruction alignment is particularly beneficial for exact multi-label prediction; this advantage is further supported by statistically significant gains when compared to general or medical initializations (see Appendix J). For MCQ Hamming, results are more balanced, with the best scores split across initialization types (two instruction-tuned, one general, and one medical). For MCQU EM, general models most frequently achieve the best performance (three cases), followed by medical models, while instruction-tuned models do not dominate. This indicates that when only a single answer must be selected, performance is driven primarily by answer plausibility ranking, favoring strong language modeling and domain knowledge, while explicit instruction alignment, which mainly benefits structured or multi-label outputs, provides less advantage. Finally, for the aggregated MCQA score, no single initialization consistently dominates: instruction-tuned and general models each obtain the best result in two configurations (with ties between them), while medical models lead in one case, and differences across initializations are often not statistically significant. 4.2 OEQA Evaluation The right side of Table 1 reports OEQA across model families using ROUGE-L, BERTScore, and LLM-as-a-Judge. We additionally report BLEU and METEOR in Appendix I, as they reflect similar information to ROUGE-L. Overall, absolute scores remain moderate, reflecting the difficulty of evaluating free-form answer generation. ROUGE-L scores should be interpreted with caution, as they measure surface-level lexical overlap and penalize semantically correct answers that differ in formulation (Yim et al., 2025; Zhu et al., 2025). Moreover, OEQA represents only 11% of the training data, resulting in a strongly imbalanced supervision signal. Models are therefore adapted to generate short, structured outputs (answer letters in MCQA), which limits OEQA performance. Effect of Adaptation Strategy: Across model families, SFT often degrades ROUGE-L and BERTScore-F1 compared to base or CPT-adapted models, particularly for instruction-tuned and medical variants. This suggests that SFT can overly constrain generation, reducing lexical diversity and semantic overlap in an open-ended setting. By contrast, CPT is the most consistently beneficial strategy for OEQA. CPT improves ROUGE-L and BERTScore-F1 across most general, instruct, and medical models, with especially strong gains for Mistral and Llama families. These results suggest that domain-adaptive language modeling supports better medical generation than instruction-level supervision alone. Combining CPT with SFT rarely outperforms CPT alone and often leads to intermediate or degraded performance, reflecting the same instability observed in MCQA, but with more pronounced negative effects in OEQA. In contrast to overlap-based metrics, LLM-as-a-Judge favors CPT+SFT in half of the configurations (6/12), compared to three cases each for the base and CPT models. Gains are most pronounced for Llama-7B, where CPT+SFT consistently outperforms SFT across initializations, and for medical models, where it yields the best or near-best qualitative scores. However, despite these trends, statistically significant improvements over the base model are rare: CPT is significant in only three cases, SFT in two (all involving smaller 4B models), and CPT+SFT never yields statistically significant gains over the base model in OEQA. Effect of Model Initialization. Initialization effects on OEQA depend strongly on the evaluation metric. For overlap-based metrics, no initialization consistently dominates: ROUGE-L is split between general and instruction-tuned models, while medical models never achieve the top score; BERTScore-F1 is mostly dominated by instruction-tuned models, with a single exception (Gemma). LLM-as-a-Judge reveals clearer and statistically grounded patterns. When differences are significant, medical models are consistently outperformed across families, particularly under SFT and CPT (Table 9). Comparisons between instruction-tuned and general models are mixed and direction-dependent, with some significant gains under SFT and CPT (notably for Mistral and Llama), but these effects largely disappear under CPT+SFT. Overall, medical initialization alone does not improve OEQA, while instruction-tuned initialization yields more reliable, yet limited, gains when significant. 5 Cross-Lingual Transfer After French Medical Adaptation Figure 2: Difference in EM accuracy (ÎâEâM EM) between native English MCQU test benchmarks and their French translations across model families and adaptation strategies (constrained decoding). To analyze whether models perform better in English prior to adaptation and how cross-lingual adaptation affects performance, we compute the EM accuracy difference for MCQU benchmarks as the score on French translations minus the score on the corresponding native English datasets. Figure 2 reports averaged results across datasets using constrained decoding; full results for both greedy and constrained decoding are provided in Appendix M. For the Mistral family, base models consistently perform better on the translated French benchmarks than on the original English data. This trend persists after adaptation with CPT, SFT, and CPT+SFT, with French performance systematically exceeding English, the differences being statistically significant (Table 13). In contrast, Gemma and Llama families show higher performance on native English benchmarks at the base level, and this advantage remains after adaptation on French data. Moreover, adaptation gains are often larger in English than in French (Table 12), despite all adaptation data being in French. These results suggest that Mistral models encode French more effectively, whereas Gemma and Llama have stronger English representations. Notably, the improvements observed in both languages indicate effective cross-lingual transfer of medical knowledge: adapting with French medical data improves performance on the original English benchmarks, sometimes more than on their French translations. This supports the complementarity of multilingual medical data, in line with Wang et al. (2024a). A salient exception is Llama-7B: before adaptation, the base model shows slightly higher performance on French translations than on English, but this difference is not statistically significant (Table 13). After adaptation, English performance surpasses French, suggesting that adaptation amplifies the modelâs dominant English representations. 6 Effect of Translated Benchmarks on Performance and Confidence Figure 3: Relationship between accuracy gain (ÎâEâM EM) and change in predictive entropy (ÎâEânâtârâoâpây Entropy) when moving from the translated to native benchmarks. Each point corresponds to a model configuration. We compare model behavior on a native benchmark, MediQAl (Bazoge, 2025), and a translated benchmark, MedMCQA (Pal et al., 2022), using accuracy and confidence-based metrics. Both benchmarks consist of MCQUs of comparable size, for fair comparison. Although instances are not shared, consistent differences across models are observed. As shown in Figure 3, all models achieve higher EM accuracy on the translated benchmark. This gain is systematically accompanied by a reduction in predictive entropy, indicating that translated benchmarks induce more confident and less uncertain predictions. The concentration of models in the bottom-right quadrant suggests that translated benchmarks operate in a different evaluation regime, characterized by both higher performance and reduced uncertainty. Figure 5 further reveals that accuracy gains are often associated with increased confidence in incorrect predictions. Most models exhibit positive shifts in confidence even when wrong, indicating a systematic overconfidence effect induced by the translated benchmark. Overall, these results show that translated benchmarks are not neutral substitutes for native ones: they tend to inflate performance while also altering model confidence calibration, potentially leading to over-optimistic evaluations. 7 Error Analysis 7.1 Probability-Level Analysis of MCQA Figure 4: Probability-level metrics for MCQ and MCQU across Mistral variants. To explain why MCQ is harder than MCQU, we analyze class probability distributions from the Mistral family, selected for its high variance across models and adaptation settings. For each item, we compute entropy, maximum probability, and a confidence gap measuring gold/non-gold separation (mean gold vs. non-gold probability in MCQ; margin to the second-best option in MCQU). We also report a near-miss rate, defined as cases where all gold answers are ranked in the top-k but the predicted set is incorrect (Figure 4, Appendix K). Across all variants, MCQ predictions are not more uncertain than MCQU: MCQ exhibits lower entropy and higher maximum probability, indicating confident local rankings. The confidence gap is consistently positive and increases with adaptation, but remains insufficient for exact multi-label generation under greedy decoding, leading to omissions or over-generation. Adaptation clarifies this effect: SFT strongly improves MCQU, while gains on MCQ remain limited. CPT+SFT primarily increases ranking confidence rather than exact set match, yielding larger confidence gaps without reducing near-miss rates. 7.2 Verbosity Bias in OEQA To better understand the differences observed between overlap-based metrics and LLM-as-a-Judge evaluations in OEQA, we analyze the length of generated answers across models. The results are reported in Appendix L. We find that CPT-adapted models systematically produce longer responses, with higher mean and median word counts across all model families. This increased verbosity provides a plausible explanation for their strong performance on ROUGE-L and BERTScore-F1, which reward lexical recall and content coverage. In contrast, instruction-tuned models generate substantially shorter and more controlled answers, particularly under SFT, often producing concise responses with low variance. While this behavior negatively impacts overlap-based metrics, it aligns with higher LLM-as-a-Judge scores, suggesting that concise answers are preferred under LLM evaluation. Finally, SFT exhibits unstable behavior in OEQA, leading either to excessively short outputs or overly long responses depending on model initialization. Overall, these results indicate that OEQA performance is strongly influenced by length biases, and that improvements in automatic metrics may partially reflect increased verbosity rather than improved answer quality. 8 Conclusion We presented a controlled and statistically grounded study of medical domain adaptation for LLMs using French medical QA, isolating the effects of model initialization, adaptation strategy, decoding, and evaluation. Our results show that adaptation effectiveness is task-dependent and that stronger strategies are not always more cost-effective. We therefore distill practical guidelines for selecting adaptation strategies based on data availability and computational constraints. Given the limited reliability of current OEQA metrics and the small proportion of OEQA supervision, our recommendations primarily emphasize MCQA, with OEQA trends interpreted cautiously. Unlabeled data only. When only unlabeled medical text is available, CPT yields modest and unstable gains for MCQA and should not be used in isolation. Its benefits mainly appear on OEQA overlap-based metrics, which are sensitive to verbosity and should be interpreted with caution. Labeled data only. With labeled QA data, SFT provides the best performanceâefficiency trade-off for MCQA across all model families. It frequently matches or exceeds CPT+SFT while requiring substantially fewer computational resources, making it the most practical default in this setting. Labeled and unlabeled data. When both data types are available, CPT+SFT most often achieves the highest MCQA scores, but improvements over SFT are typically small and not consistently statistically significant. Consequently, CPT+SFT is justified only when maximal performance outweighs computational cost. Initialization and compute considerations. Instruction-tuned models constitute the strongest baseline for French medical MCQA. Medical initialization alone does not reliably improve downstream performance. From a resource perspective, parameter-efficient SFT is by far the most cost-effective strategy, whereas CPT incurs high computational and environmental costs for limited MCQA gains, and CPT+SFT compounds these costs for marginal improvements. Evaluation and transfer considerations. Finally, we observe strong evaluation effects: adaptation on French medical data transfers to English benchmarks, translated datasets inflate both accuracy and confidence, and OEQA metrics are sensitive to verbosity. These findings highlight the need for task-aware adaptation choices and cautious metric interpretation in medical LLM evaluation. 9 Limitations Our evaluation of adaptation strategies faces several limitations. First, we perform an exploratory contamination study to assess possible exposure to NACHOS during pretraining (Appendix P). Although no direct evidence of memorization is observed, likelihood-based tests remain inconclusive due to the lack of a reliable non-member biomedical control corpus, requiring the use of synthetic controls. We therefore treat these results as indicative only and avoid causal conclusions about pretraining inclusion. Second, our evaluation of OEQA relies on overlap-based metrics, BERTScore, and LLM-as-a-Judge. While these measures capture complementary aspects of answer quality, they do not fully characterize semantic equivalence, clinical correctness, or reasoning validity, and may therefore overlook qualitative differences between correct answers (Yim et al., 2025; Zhu et al., 2025). Third, while we demonstrate the efficiency of SFT compared to CPT in terms of computational resources, our analysis does not account for the human effort required to create high-quality instruction-tuning datasets. This consideration is particularly relevant for low-resource settings where creating domain-specific instruction data may be costly. Fourth, we do not include few-shot prompting as an evaluation setting. Our objective is to isolate the effects of parameter-level adaptation strategies under controlled and reproducible conditions. Few-shot prompting introduces additional sources of variance related to example selection, ordering, and prompt design, which would complicate statistical comparison and obscure the interpretation of adaptation gains. Moreover, few-shot prompting assumes access to curated task-specific examples at inference time, which may be unrealistic in medical deployment scenarios. For these reasons, we focus on zero-shot evaluation to ensure fair and stable comparisons across adaptation strategies. Finally, our study focuses exclusively on CPT and SFT. We do not explore reinforcement learningâbased adaptation strategies, such as preference optimization or reward-driven fine-tuning, which may better align models with clinical judgment or evaluation criteria. Investigating how such methods interact with CPT and SFT, particularly under multilingual and domain-specific constraints, constitutes an important direction for future work. In addition, our findings about the effectiveness of adaptation strategies are specific to the medical domain and French language. The generalizability of these results to other domains or languages, particularly those with different resource constraints or linguistic characteristics, requires further investigation. 10 Ethical Considerations This work is intended for research purposes only and not for direct clinical use. All experiments rely on publicly available biomedical datasets without identifiable patient data. 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While the full corpus spans 7.4 GB of data and contains over one billion words sourced from 24 French-speaking high-quality websites (Labrak et al., 2023), we use in this work its small variant, NACHOSsmall. This version consists of approximately 4 GB of data and was obtained by shuffling the full corpus and randomly selecting 25.3 million sentences to ensure homogeneous coverage of data sources. Note: Full details of the corpus compilation and processing are available in the original paper (Labrak et al., 2023). A.1 Corpus Composition The NACHOS corpus encompasses a diverse range of medical textual sources, including: âą Descriptions of diseases and conditions âą Treatment and medication information âą General health-related advice âą Official scientific meeting reports âą Anonymized clinical cases âą Scientific literature âą Theses âą French translation pairs âą University health courses A.2 Data Sources The corpus integrates data from multiple sources, with the most significant contributions coming from: âą HAL (638,508,261 words) âą Haute AutoritĂ© de SantĂ© (HAS) (113,394,539 words) âą Drug leaflets (74,770,229 words) âą Medical Websites Scraping (60,561,495 words) âą ANSES SAISINE (51,372,932 words) âą Public Drug Database (BDPM) (48,302,695 words) A.3 Corpus Preparation The researchers employed several preprocessing steps: 1. Text collection through web scraping, raw textual sources, and optical character recognition (OCR) 2. Sentence splitting using heuristic methods 3. Aggressive filtering to remove short or low-quality sentences 4. Language classification using a custom classifier trained on multilingual corpora Appendix B SFT Training Corpus : MedInjection-Fr Description B.1 Overview MedInjection-FR (Belmadani et al., 2026b) is a large-scale French biomedical instruction dataset composed of native, translated, and synthetic instructionâresponse pairs. The dataset comprises 571 436 examples spanning MCQUs, MCQs, and OEQAs. B.2 Data Composition The dataset consists of 77 247 native examples, 417 674 translated examples, and 76 506 synthetic examples. All data are formatted as instructionâresponse pairs and normalized to a unified schema, ensuring consistency across heterogeneous sources and supervision types. B.3 Quality Control for Translated Data The translated subset was obtained by translating English biomedical instruction datasets into French using two LLMs: GPT-4o-mini (Hurst et al., 2024) and Gemini 2.0 Flash 222https://cloud.google.com/vertex-ai/generative-ai/docs/models/gemini/2-0-flash. Translation quality was evaluated on the WMT 2024 Biomedical Translation Task benchmark (Neves et al., 2024) using BLEU and COMET metrics. GPT-4o-mini achieved a BLEU score of 51.01 and a COMET score of 0.8751, while Gemini 2.0 Flash achieved a BLEU score of 53.72 and a COMET score of 0.8783. These results are comparable to the best-performing system reported in the shared task (BLEU 53.54, COMET 0.8760), suggesting high semantic fidelity and robust preservation of biomedical terminology in the translated subset. B.4 Quality Control for Synthetic Data The synthetic subset was generated using GPT-4o from source documents including clinical cases and biomedical abstracts. Each source document was used to generate multiple instructional tasks covering a broad range of biomedical reasoning, such as clinical summarization, factual QA, diagnostic reasoning, treatment suggestion, and classification. To control generation quality, each synthetic instructionâresponse pair was evaluated using four independent large language models acting as automatic judges: GPT-4.1-mini 333https://openai.com/index/gpt-4-1/, Gemini 2.0 Flash, MedGemma-27B (Sellergren et al., 2025), and Qwen3-Next-80B-A3B-Instruct (Team, 2025). For MCQAs, evaluators assigned scores on a three-point scale reflecting answer correctness and contextual coherence. For OEQAs, a five-point scale was used to capture varying degrees of factual accuracy and completeness. Only examples meeting predefined minimum quality thresholds across evaluators were retained in the final dataset. Appendix C CPT hyperparameters Parameter Value Learning rate 2e-05 (1e-04 for gemma family) Train batch size 2 (4 for gema family) Seed 42 Gradient accumulation steps 2 (16 for gemma family) Optimizer AdamW Weight Decay 0.01 Scheduler Cosine Number of epochs 3 Table 2: Hyperparameters used in CPT training Appendix D SFT hyperparameters Parameter Value Rank 16 LoRA Aplha 16 LoRA Dropout 0.05 use_dora True Learning rate 2e-05 (1e-04 for gemma family) Train batch size 4 Evaluation batch size train_batch_size * 2 Seed 42 WarmUp_ratio 0.05 Gradient accumulation steps 8 Optimizer AdamW Scheduler Cosine Number of epochs 10 Target Modules QKVOGUD Table 3: Hyperparameters used in SFT training Appendix E Preliminary Comparison of Full Fine-Tuning and PEFT To justify our choice of parameter-efficient fine-tuning (PEFT) for SFT, we conducted preliminary experiments comparing full fine-tuning with several PEFT methods on the FrenchMedMCQA dataset (Labrak et al., 2022). We evaluated LoRA (Hu et al., 2022), DoRA (Mao et al., 2024), and VeRA (Kopiczko et al., 2024) against full-parameter fine-tuning using identical training configurations. Results are reported in Table 4. LoRA DoRA VeRA Full FT Exact Match 0.2211 0.2435 0.1153 0.1121 Hamming Distance 0.4325 0.4627 0.3482 0.3143 Trainable Params (%) 0.583 0.602 0.0037 100 Table 4: Comparison of full fine-tuning and parameter-efficient methods on FrenchMedMCQA. We observe that PEFT methods, particularly DoRA, outperform full fine-tuning while requiring significantly fewer trainable parameters. In addition, full fine-tuning exhibited higher overfitting tendencies, with faster training loss convergence but weaker generalization performance on validation data. These results support the use of parameter-efficient methods for SFT in our main experiments, as they provide a better trade-off between performance, efficiency, and generalization. Appendix F Evaluation Metrics We provide here the formal definitions of the evaluation metrics used for MCQU and MCQ evaluation. Exact Match (EM). Exact Match measures the proportion of predictions that exactly match the gold answer: EM=1Nââi=1N[y^i=yi],EM= 1N _i=1^N[ y_i=y_i], where N denotes the number of questions, yiy_i the gold answer, y^i y_i the model prediction, and [â ][·] is the indicator function. Hamming Score. For multi-answer MCQ, we additionally report the Hamming score, which captures partial agreement between predicted and reference label sets: Hamming Score=1Nââi=1N|yiâ©y^i||yiâȘy^i|.Hamming Score= 1N _i=1^N |y_iâ© y_i||y_iâȘ y_i|. This metric rewards partial correctness and is therefore better suited for evaluating multi-label predictions than Exact Match alone. Appendix G Evaluation Benchmarks The adapted models are evaluated against their corresponding base models using benchmark datasets drawn from the test split of MedInjection-FR. The evaluation suite includes both native French benchmarks and translated English benchmarks. For the translated benchmarks, English test sets were translated into French following the procedure described in section B.3. The benchmarks cover multiple task formats, including MCQU, MCQ and OEQA. This setup enables a controlled comparison of adaptation effects across both discriminative and generative biomedical reasoning tasks. Table 5 summarizes the datasets used for evaluation and their respective sizes. Dataset # Items Task [HTML]DAE8FCNATIVE 3 384 MCQ 4 343 MCQU MediQAl (Bazoge, 2025) 4 969 OEQA FrenchMedMCQA (Labrak et al., 2022) 622 MCQ mlabonne/medical-mcqa-fr444https://huggingface.co/datasets/mlabonne/medical-cases-fr 150 MCQ mlabonne/medical-cases-fr555https://huggingface.co/datasets/mlabonne/medical-mqca-fr 352 MCQ FrBMedQA (Kaddari and Bouchentouf, 2022) 187 MCQU 343 OEQA S-Editions666https://s-editions.fr/ 183 MCQ [HTML]DAE8FCTRANSLATED MedQA_4options (Jin et al., 2021) 1 273 MCQU MedQA_5options (Jin et al., 2021) 1 273 MCQU PubMedQA (Jin et al., 2019) 500 MCQU MedMCQA (Pal et al., 2022) 4 183 MCQU MMLU (Hendrycks et al., 2021) 1 080 MCQU K-QA (Manes et al., 2024) 201 OEQA MMLU-PRO (Wang et al., 2024b) 2 333 MCQU MedXpertQA (Zuo et al., 2025) 2 450 MCQU Table 5: Evaluation benchmarks used to compare adapted models with their base counterparts. All datasets correspond to the test split of MedInjection-FR. Appendix H Prompt Templates Overview. We use a unified instruction format across all task types, both for supervised fine-tuning and for zero-shot evaluation. When available, we rely on the native chat templates provided by instruction-tuned models; otherwise, prompts are formatted as plain-text instructionâresponse pairs. Shared Structure. All prompts begin with a high-level medical instruction, optionally followed by a contextual passage. The core components are: 1. an instruction describing the task, 2. the question (and answer options when applicable), 3. an optional context section, and 4. a response header indicating where the model output should begin. Task-Specific Constraints. The only variation across task types lies in the expected response format, which is explicitly stated in the instruction. Table 6 summarizes the templates used for each task. Task Instruction Constraint Expected Output MCQU Respond only with the letter corresponding to the single correct answer. Single letter (e.g., A) MCQ Respond only with the letters corresponding to all correct answers, separated by commas. Comma-separated letters (e.g., A, C, D) OEQA Provide a free-form medical answer based on the instruction and context. Unconstrained text Table 6: Summary of task-specific prompt templates and output constraints. Canonical Prompt Format. The following abstract template illustrates the prompt structure shared across all tasks: System prompt (training and evaluation) for MCQ ⏠Lire lâinstruction mĂ©dicale suivante et fournir une rĂ©ponse adaptĂ©e Ă la situation dĂ©crite. RĂ©pondre uniquement avec la lettre correspondant Ă la ou les bonnes rĂ©ponses sĂ©parĂ©es par des virgules. Exemple : A, C, D. System prompt (training and evaluation) for MCQU ⏠Lire lâinstruction mĂ©dicale suivante et fournir une rĂ©ponse adaptĂ©e Ă la situation dĂ©crite. RĂ©pondre uniquement avec la lettre correspondant Ă la bonne rĂ©ponse. Exemple : A. System prompt (training and evaluation) for OEQA ⏠Lire lâinstruction mĂ©dicale suivante et fournir une rĂ©ponse adaptĂ©e Ă la situation dĂ©crite. User prompt (task-dependent) ⏠### Instruction: [Question (+ options for MCQ tasks)] ### Contexte: [Context, if available] ### RĂ©ponse: Chat-Based Formatting. For instruction-tuned models providing an explicit chat interface, the same content is mapped to role-based messages as follows: âą System: high-level medical instruction (shared across tasks), âą User: task instruction, question, and optional context, âą Assistant: model-generated answer. This formulation ensures consistent supervision and evaluation across models with different input formatting requirements. Appendix I MCQA and OEQA Results MCQ MCQU Aggregation OEQA Model Type Strategy EM Hamming EM EM BLEU METEOR [HTML]CFE2F3Gemma-4B Base 0.56 5.15 5.88 3.22 0.92 8.09 CPT 0.03 0.68 8.53 4.28 1.68 8.35 SFT 1.73 19.48 19.81 10.77 1.03 7.42 GENERAL CPT+SFT 1.67 15.34 19.52 10.60 0.56 6.99 Base 6.81 40.75 28.88 17.85 0.76 10.41 CPT 0.07 1.72 1.37 0.72 0.46 5.89 SFT 1.38 10.17 31.87 16.63 0.09 5.32 INSTRUCT CPT+SFT 1.22 8.61 30.66 15.94 0.21 6.93 Base 1.22 11.28 11.47 6.34 0.76 10.41 CPT 1.62 18.11 11.18 6.40 1.04 5.26 SFT 1.15 11.51 17.91 9.53 0.56 6.98 MEDICAL CPT+SFT 1.67 16.54 17.63 9.65 0.34 5.60 [HTML]CFE2F3Mistral-7B Base 0.15 2.90 4.04 2.09 0.66 7.32 CPT 0.44 3.75 13.71 7.07 0.99 7.69 SFT 1.79 20.62 19.88 10.84 1.04 7.59 GENERAL CPT+SFT 1.42 17.95 19.57 10.49 0.63 8.66 Base 3.42 26.94 21.46 12.44 1.12 7.70 CPT 4.10 29.16 27.63 15.87 2.34 10.90 SFT 11.94 47.39 31.52 21.73 1.65 7.08 INSTRUCT CPT+SFT 1.85 17.56 29.84 15.85 1.09 9.46 Base 2.24 19.09 13.39 7.81 1.73 8.39 CPT 2.25 18.39 12.19 7.22 1.93 9.54 SFT 1.95 20.68 18.47 10.21 1.06 6.75 MEDICAL CPT+SFT 1.44 16.43 19.33 10.38 1.05 8.02 [HTML]CFE2F3Llama-7B Base 0.17 2.69 9.46 4.82 0.49 5.91 CPT 1.13 10.16 5.83 3.48 1.39 5.90 SFT 1.82 24.64 16.08 8.95 0.51 7.26 GENERAL CPT+SFT 1.61 17.50 17.11 9.36 0.52 6.75 Base 0.03 0.64 0.04 0.03 0.40 2.51 CPT 4.92 40.87 0.04 2.48 1.72 8.64 SFT 7.72 42.70 29.26 18.49 1.42 6.22 INSTRUCT CPT+SFT 1.03 6.36 0.07 0.55 1.41 10.07 Base 0.14 1.98 0.57 0.35 0.51 7.06 CPT 2.11 24.01 12.20 7.16 1.12 5.69 SFT 1.12 20.40 17.49 9.30 0.40 5.50 MEDICAL CPT+SFT 1.67 15.87 18.29 9.98 0.49 6.70 [HTML]CFE2F3Llama-13B Base 0.29 0.84 11.77 6.03 0.19 1.98 CPT 2.81 21.03 10.49 6.65 1.85 7.85 SFT 2.18 17.08 18.67 10.42 0.42 5.85 GENERAL CPT+SFT 1.65 21.56 19.84 10.74 0.59 8.07 Base 0.00 4.87 0.04 0.02 0.50 3.85 CPT 4.82 34.09 0.04 2.43 2.09 10.78 SFT 10.92 42.98 30.13 20.53 1.52 6.52 INSTRUCT CPT+SFT 12.57 44.02 31.48 22.02 1.74 7.32 Base 0.56 9.41 11.01 5.78 0.48 5.60 CPT 2.02 22.25 11.28 6.65 1.12 5.69 SFT 2.07 21.50 18.11 10.09 0.59 7.37 MEDICAL CPT+SFT 1.61 17.64 19.75 10.68 0.67 6.53 Table 7: Greedy decoding results for MCQ and MCQU and BLEU/METEOR scores for OEQA across model families and adaptation strategies. Bold denotes the best strategy and the best initialization. I.1 MCQA Greedy Decoding Table 7 reports performance on MCQA across the studied model families (Gemma-4B, Mistral-7B, Llama-7B, and Llama-13B), three initialization types (General, Instruct, Medical), and four adaptation strategies (Base, CPT, SFT, CPT+SFT). Results are shown for both standard multiple-answer MCQs (MCQ) and single-answer MCQs (MCQU), using Exact Match (EM), Hamming score for MCQ, and aggregated EM. The reported results here are obtained using greedy decoding. Effectiveness of Adaptation Strategy: Under greedy decoding, SFT clearly dominates all other adaptation strategies across MCQ, MCQU, and aggregated metrics. Unlike constrained decoding, where CPT+SFT often ranks first, greedy decoding exposes a much sharper separation between strategies: BaseâȘCPT âȘCPT+SFT <SFT Base [rgb]0,0,1 [named]pgfstrokecolorrgb0,0,1CPT [rgb]1,0,0 [named]pgfstrokecolorrgb1,0,0CPT+SFT < [rgb]0,0.6,0 [named]pgfstrokecolorrgb0,0.6,0SFT Across nearly all model families and initializations, SFT yields the highest MCQ EM, MCQ Hamming, MCQU EM, and aggregated EM. This trend is particularly strong for instruction-tuned models (Mistral, Llama-7B, Llama-13B), where SFT consistently delivers large absolute gains, often by wide margins. As in the constrained decoding setting, when CPT+SFT outperforms SFT, the performance gap is generally smaller than in configurations where SFT outperforms CPT+SFT. CPT alone remains unstable under greedy decoding. While it sometimes improves over the base model, it frequently underperforms SFT and can even degrade MCQU and aggregated scores. Importantly, CPT+SFT does not systematically improve over SFT in greedy decoding and often performs worse, indicating that the benefits of CPT are largely redundant once task supervision is introduced and decoding constraints are removed. Overall, greedy decoding amplifies the advantages of task-aligned supervision, making SFT the best adaptation strategy when decoding is unconstrained. Impact of Model Initialization: Model initialization plays a stronger and more consistent role under greedy decoding than under constrained decoding. Across all families and metrics, instruction-tuned models dominate. General models benefit from SFT but remain consistently below instruction-tuned counterparts. Medical models, while improving with SFT, never achieve the best greedy decoding performance, confirming that domain pretraining alone is insufficient without strong instruction alignment. This contrasts with constrained decoding, where general and medical models occasionally remain competitive. Under greedy decoding, instruction tuning becomes a necessary condition for strong performance. MCQA Greedy Decoding Guidelines: For greedy decoding in medical MCQA, the optimal configuration is to start from an instruction-tuned model and apply SFT only. CPT and CPT+SFT offer no consistent benefit in this setting and can be safely avoided unless constrained decoding is explicitly required. I.2 OEQA Overlap-based Evaluation The right part of Table 7 reports the overlap-based metrics BLEU and METEOR. Both metrics exhibit trends consistent with ROUGE-L, with improvements primarily driven by CPT. In a few isolated cases, CPT+SFT yields additional gains on METEOR, but with small differences with when compared with CPT. Regarding model initialization, BLEU and METEOR consistently favor instruction-tuned models as the strongest starting point. Appendix J Statistical Significance id strategy model_a model_b Decoding type ci95_low ci95_high p_two_sided alpha_Bonferoni significant_Bonferroni [HTML]CFE2F3Gemma 4B A1 CPT gemma-3-4b-pt-CPT gemma-3-4b-pt constrained -2.60E-02 -3.48E-03 2.00E-04 4.17E-03 TRUE A1 CPT gemma-3-4b-pt-CPT gemma-3-4b-pt greedy -6.03E-03 2.71E-02 1.75E-01 4.17E-03 FALSE A2 CPT+SFT gemma-3-4b-pt-CPT-SFT gemma-3-4b-pt constrained 1.57E-02 5.29E-02 4.00E-04 4.17E-03 TRUE A2 CPT+SFT gemma-3-4b-pt-CPT-SFT gemma-3-4b-pt greedy 6.03E-02 9.37E-02 2.00E-04 4.17E-03 TRUE A3 CPT+SFT gemma-3-4b-pt-CPT-SFT gemma-3-4b-pt-CPT constrained 2.34E-02 7.52E-02 2.00E-04 4.17E-03 TRUE A3 CPT+SFT gemma-3-4b-pt-CPT-SFT gemma-3-4b-pt-CPT greedy 4.06E-02 9.63E-02 2.00E-04 4.17E-03 TRUE A4 SFT gemma-3-4b-pt-SFT gemma-3-4b-pt constrained 1.32E-02 4.90E-02 2.00E-04 4.17E-03 TRUE GENERAL A4 SFT gemma-3-4b-pt-SFT gemma-3-4b-pt greedy 6.17E-02 9.54E-02 2.00E-04 4.17E-03 TRUE B1 CPT gemma-3-4b-it-CPT gemma-3-4b-it constrained -4.69E-02 -8.61E-03 4.00E-03 4.17E-03 TRUE B1 CPT gemma-3-4b-it-CPT gemma-3-4b-it greedy -1.94E-01 -1.47E-01 2.00E-04 4.17E-03 TRUE B2 CPT+SFT gemma-3-4b-it-CPT-SFT gemma-3-4b-it constrained -1.25E-02 1.41E-02 9.27E-01 4.17E-03 FALSE B2 CPT+SFT gemma-3-4b-it-CPT-SFT gemma-3-4b-it greedy -3.54E-02 -2.16E-03 2.66E-02 4.17E-03 FALSE B3 CPT+SFT gemma-3-4b-it-CPT-SFT gemma-3-4b-it-CPT constrained 1.49E-02 4.29E-02 2.00E-04 4.17E-03 TRUE B3 CPT+SFT gemma-3-4b-it-CPT-SFT gemma-3-4b-it-CPT greedy 1.26E-01 1.78E-01 2.00E-04 4.17E-03 TRUE B4 SFT gemma-3-4b-it-SFT gemma-3-4b-it constrained -5.48E-03 2.13E-02 2.77E-01 4.17E-03 FALSE INSTRUCT B4 SFT gemma-3-4b-it-SFT gemma-3-4b-it greedy -2.62E-02 3.58E-03 1.23E-01 4.17E-03 FALSE C1 CPT medgemma-4b-pt-CPT medgemma-4b-pt constrained -1.68E-02 1.67E-04 5.60E-02 4.17E-03 FALSE C1 CPT medgemma-4b-pt-CPT medgemma-4b-pt greedy -4.32E-03 9.75E-03 4.60E-01 4.17E-03 FALSE C2 CPT+SFT medgemma-4b-pt-CPT-SFT medgemma-4b-pt-CPT constrained 2.64E-02 4.73E-02 2.00E-04 4.17E-03 TRUE C2 CPT+SFT medgemma-4b-pt-CPT-SFT medgemma-4b-pt-CPT greedy 2.44E-02 3.98E-02 2.00E-04 4.17E-03 TRUE C3 CPT+SFT medgemma-4b-pt-CPT-SFT medgemma-4b-pt constrained 1.72E-02 4.13E-02 2.00E-04 4.17E-03 TRUE C3 CPT+SFT medgemma-4b-pt-CPT-SFT medgemma-4b-pt greedy 2.80E-02 4.25E-02 2.00E-04 4.17E-03 TRUE C4 SFT medgemma-4b-pt-SFT medgemma-4b-pt constrained 1.74E-02 4.04E-02 2.00E-04 4.17E-03 TRUE MEDICAL C4 SFT medgemma-4b-pt-SFT medgemma-4b-pt greedy 2.58E-02 4.14E-02 2.00E-04 4.17E-03 TRUE D1 SFT gemma-3-4b-pt-SFT gemma-3-4b-it-SFT constrained -7.13E-03 1.15E-02 6.83E-01 5.56E-03 FALSE D1 SFT gemma-3-4b-pt-SFT gemma-3-4b-it-SFT greedy -6.92E-02 -4.32E-02 2.00E-04 5.56E-03 TRUE D2 SFT gemma-3-4b-pt-SFT medgemma-4b-pt-SFT constrained 2.60E-03 1.27E-02 4.80E-03 5.56E-03 TRUE D2 SFT gemma-3-4b-pt-SFT medgemma-4b-pt-SFT greedy 8.83E-03 1.61E-02 2.00E-04 5.56E-03 TRUE D3 SFT gemma-3-4b-it-SFT medgemma-4b-pt-SFT constrained -5.57E-03 1.57E-02 3.13E-01 5.56E-03 FALSE SFT D3 SFT gemma-3-4b-it-SFT medgemma-4b-pt-SFT greedy 5.63E-02 8.12E-02 2.00E-04 5.56E-03 TRUE E1 CPT gemma-3-4b-pt-CPT gemma-3-4b-it-CPT constrained -3.76E-02 2.01E-02 7.90E-01 5.56E-03 FALSE E1 CPT gemma-3-4b-pt-CPT gemma-3-4b-it-CPT greedy 2.58E-02 4.95E-02 2.00E-04 5.56E-03 TRUE E2 CPT gemma-3-4b-pt-CPT medgemma-4b-pt-CPT constrained -2.87E-02 2.19E-02 8.35E-01 5.56E-03 FALSE E2 CPT gemma-3-4b-pt-CPT medgemma-4b-pt-CPT greedy -5.66E-02 1.81E-03 8.56E-02 5.56E-03 FALSE E3 CPT gemma-3-4b-it-CPT medgemma-4b-pt-CPT constrained -2.21E-03 1.59E-02 1.83E-01 5.56E-03 FALSE CPT E3 CPT gemma-3-4b-it-CPT medgemma-4b-pt-CPT greedy -9.23E-02 -3.78E-02 2.00E-04 5.56E-03 TRUE F1 CPT+SFT gemma-3-4b-pt-CPT-SFT gemma-3-4b-it-CPT-SFT constrained 2.15E-03 2.27E-02 1.92E-02 5.56E-03 FALSE F1 CPT+SFT gemma-3-4b-pt-CPT-SFT gemma-3-4b-it-CPT-SFT greedy -6.81E-02 -3.28E-02 2.00E-04 5.56E-03 TRUE F2 CPT+SFT gemma-3-4b-pt-CPT-SFT medgemma-4b-pt-CPT-SFT constrained 2.64E-03 1.80E-02 1.10E-02 5.56E-03 FALSE F2 CPT+SFT gemma-3-4b-pt-CPT-SFT medgemma-4b-pt-CPT-SFT greedy 3.47E-03 1.52E-02 1.60E-03 5.56E-03 TRUE F3 CPT+SFT gemma-3-4b-it-CPT-SFT medgemma-4b-pt-CPT-SFT constrained -1.27E-02 9.11E-03 7.58E-01 5.56E-03 FALSE CPT+SFT F3 CPT+SFT gemma-3-4b-it-CPT-SFT medgemma-4b-pt-CPT-SFT greedy 3.84E-02 7.95E-02 2.00E-04 5.56E-03 TRUE [HTML]CFE2F3Mistral 7B A1 CPT Mistral-7B-v0.1-CPT Mistral-7B-v0.1 constrained 1.63E-03 2.19E-02 2.26E-02 4.17E-03 FALSE A1 CPT Mistral-7B-v0.1-CPT Mistral-7B-v0.1 greedy 3.64E-02 6.00E-02 2.00E-04 4.17E-03 TRUE A2 CPT+SFT Mistral-7B-v0.1-CPT-SFT Mistral-7B-v0.1 constrained 3.71E-02 6.85E-02 2.00E-04 4.17E-03 TRUE A2 CPT+SFT Mistral-7B-v0.1-CPT-SFT Mistral-7B-v0.1 greedy 6.72E-02 1.01E-01 2.00E-04 4.17E-03 TRUE A3 CPT+SFT Mistral-7B-v0.1-CPT-SFT Mistral-7B-v0.1-CPT constrained 2.80E-02 5.41E-02 2.00E-04 4.17E-03 TRUE A3 CPT+SFT Mistral-7B-v0.1-CPT-SFT Mistral-7B-v0.1-CPT greedy 2.82E-02 4.38E-02 2.00E-04 4.17E-03 TRUE A4 SFT Mistral-7B-v0.1-SFT Mistral-7B-v0.1 constrained 3.25E-02 6.88E-02 2.00E-04 4.17E-03 TRUE GENERAL A4 SFT Mistral-7B-v0.1-SFT Mistral-7B-v0.1 greedy 7.41E-02 1.06E-01 2.00E-04 4.17E-03 TRUE B1 CPT Mistral-7B-Instruct-v0.1-CPT Mistral-7B-Instruct-v0.1 constrained 1.76E-02 4.88E-02 2.00E-04 4.17E-03 TRUE B1 CPT Mistral-7B-Instruct-v0.1-CPT Mistral-7B-Instruct-v0.1 greedy 1.67E-02 5.01E-02 2.00E-04 4.17E-03 TRUE B2 CPT+SFT Mistral-7B-Instruct-v0.1-CPT-SFT Mistral-7B-Instruct-v0.1-CPT constrained -2.10E-02 1.47E-02 7.64E-01 4.17E-03 FALSE B2 CPT+SFT Mistral-7B-Instruct-v0.1-CPT-SFT Mistral-7B-Instruct-v0.1-CPT greedy -1.59E-02 1.76E-02 9.83E-01 4.17E-03 FALSE B3 CPT+SFT Mistral-7B-Instruct-v0.1-CPT-SFT Mistral-7B-Instruct-v0.1 constrained 1.29E-02 5.00E-02 2.00E-04 4.17E-03 TRUE B3 CPT+SFT Mistral-7B-Instruct-v0.1-CPT-SFT Mistral-7B-Instruct-v0.1 greedy 1.68E-02 5.21E-02 2.00E-04 4.17E-03 TRUE B4 SFT Mistral-7B-Instruct-v0.1-SFT Mistral-7B-Instruct-v0.1 constrained 2.41E-02 6.41E-02 2.00E-04 4.17E-03 TRUE INSTRUCT B4 SFT Mistral-7B-Instruct-v0.1-SFT Mistral-7B-Instruct-v0.1 greedy 6.71E-02 1.18E-01 2.00E-04 4.17E-03 TRUE C1 CPT BioMistral-7B-CPT BioMistral-7B constrained -1.12E-02 1.00E-02 8.13E-01 4.17E-03 FALSE C1 CPT BioMistral-7B-CPT BioMistral-7B greedy -1.61E-02 2.51E-03 2.85E-01 4.17E-03 FALSE C2 CPT+SFT BioMistral-7B-CPT-SFT BioMistral-7B constrained 2.63E-02 6.50E-02 2.00E-04 4.17E-03 TRUE C2 CPT+SFT BioMistral-7B-CPT-SFT BioMistral-7B greedy 1.33E-02 4.54E-02 2.00E-04 4.17E-03 TRUE C3 CPT+SFT BioMistral-7B-CPT-SFT BioMistral-7B-CPT constrained 2.23E-02 7.24E-02 2.00E-04 4.17E-03 TRUE C3 CPT+SFT BioMistral-7B-CPT-SFT BioMistral-7B-CPT greedy 1.27E-02 6.02E-02 2.00E-04 4.17E-03 TRUE C4 SFT BioMistral-7B-SFT BioMistral-7B constrained 1.33E-02 4.67E-02 2.00E-04 4.17E-03 TRUE MEDICAL C4 SFT BioMistral-7B-SFT BioMistral-7B greedy 1.34E-02 4.18E-02 2.00E-04 4.17E-03 TRUE D1 SFT Mistral-7B-v0.1-SFT Mistral-7B-Instruct-v0.1-SFT constrained -1.89E-02 2.68E-02 7.28E-01 5.56E-03 FALSE D1 SFT Mistral-7B-v0.1-SFT Mistral-7B-Instruct-v0.1-SFT greedy -1.32E-01 -8.16E-02 2.00E-04 5.56E-03 TRUE D2 SFT Mistral-7B-Instruct-v0.1-SFT BioMistral-7B-SFT constrained -1.41E-02 4.27E-02 4.35E-01 5.56E-03 FALSE D2 SFT Mistral-7B-Instruct-v0.1-SFT BioMistral-7B-SFT greedy 8.72E-02 1.40E-01 2.00E-04 5.56E-03 TRUE D3 SFT Mistral-7B-v0.1-SFT BioMistral-7B-SFT constrained 5.20E-03 2.93E-02 2.00E-03 5.56E-03 TRUE SFT D3 SFT Mistral-7B-v0.1-SFT BioMistral-7B-SFT greedy 1.57E-03 1.27E-02 1.66E-02 5.56E-03 FALSE E1 CPT Mistral-7B-v0.1-CPT Mistral-7B-Instruct-v0.1-CPT constrained -5.11E-02 -3.56E-04 4.62E-02 5.56E-03 FALSE E1 CPT Mistral-7B-v0.1-CPT Mistral-7B-Instruct-v0.1-CPT greedy -1.07E-01 -6.53E-02 2.00E-04 5.56E-03 TRUE E2 CPT Mistral-7B-v0.1-CPT BioMistral-7B-CPT constrained -9.26E-03 2.57E-02 6.18E-01 5.56E-03 FALSE E2 CPT Mistral-7B-v0.1-CPT BioMistral-7B-CPT greedy -1.44E-02 1.70E-02 6.45E-01 5.56E-03 FALSE E3 CPT Mistral-7B-Instruct-v0.1-CPT BioMistral-7B-CPT constrained 4.02E-03 5.94E-02 1.80E-02 5.56E-03 FALSE CPT E3 CPT Mistral-7B-Instruct-v0.1-CPT BioMistral-7B-CPT greedy 6.80E-02 1.01E-01 2.00E-04 5.56E-03 TRUE F1 CPT+SFT Mistral-7B-v0.1-CPT-SFT Mistral-7B-Instruct-v0.1-CPT-SFT constrained 7.69E-03 3.25E-02 1.20E-03 5.56E-03 TRUE F1 CPT+SFT Mistral-7B-v0.1-CPT-SFT Mistral-7B-Instruct-v0.1-CPT-SFT greedy -6.20E-02 -4.21E-02 2.00E-04 5.56E-03 TRUE F2 CPT+SFT Mistral-7B-v0.1-CPT-SFT BioMistral-7B-CPT-SFT constrained -9.97E-03 1.59E-02 5.02E-01 5.56E-03 FALSE F2 CPT+SFT Mistral-7B-v0.1-CPT-SFT BioMistral-7B-CPT-SFT greedy -1.08E-02 9.42E-03 6.69E-01 5.56E-03 FALSE F3 CPT+SFT Mistral-7B-Instruct-v0.1-CPT-SFT BioMistral-7B-CPT-SFT constrained -3.06E-02 -1.28E-03 3.42E-02 5.56E-03 FALSE CPT+SFT F3 CPT+SFT Mistral-7B-Instruct-v0.1-CPT-SFT BioMistral-7B-CPT-SFT greedy 3.56E-02 6.81E-02 2.00E-04 5.56E-03 TRUE [HTML]CFE2F3Llama 7B A1 CPT Llama-2-7b-hf-CPT Llama-2-7b-hf constrained -8.99E-03 4.70E-03 6.17E-01 4.17E-03 FALSE A1 CPT Llama-2-7b-hf-CPT Llama-2-7b-hf greedy -2.29E-02 -4.41E-03 3.00E-03 4.17E-03 TRUE A2 CPT+SFT LLama-2-7b-hf-CPT-SFT Llama-2-7b-hf-CPT constrained 2.06E-02 4.76E-02 2.00E-04 4.17E-03 TRUE A2 CPT+SFT LLama-2-7b-hf-CPT-SFT Llama-2-7b-hf-CPT greedy 4.28E-02 8.52E-02 2.00E-04 4.17E-03 TRUE A3 CPT+SFT LLama-2-7b-hf-CPT-SFT Llama-2-7b-hf constrained 1.81E-02 4.46E-02 2.00E-04 4.17E-03 TRUE A3 CPT+SFT LLama-2-7b-hf-CPT-SFT Llama-2-7b-hf greedy 3.37E-02 6.48E-02 2.00E-04 4.17E-03 TRUE A4 SFT LLama-2-7b-hf-SFT Llama-2-7b-hf constrained 1.58E-02 3.86E-02 2.00E-04 4.17E-03 TRUE GENERAL A4 SFT LLama-2-7b-hf-SFT Llama-2-7b-hf greedy 3.08E-02 6.12E-02 2.00E-04 4.17E-03 TRUE B1 CPT Llama-2-7b-chat-hf-CPT Llama-2-7b-chat-hf constrained -7.23E-03 4.04E-03 8.20E-01 4.17E-03 FALSE B1 CPT Llama-2-7b-chat-hf-CPT Llama-2-7b-chat-hf greedy 1.86E-02 3.22E-02 2.00E-04 4.17E-03 TRUE B2 CPT+SFT Llama-2-7b-chat-hf-CPT-SFT Llama-2-7b-chat-hf constrained -1.32E-02 2.43E-03 2.78E-01 4.17E-03 FALSE B2 CPT+SFT Llama-2-7b-chat-hf-CPT-SFT Llama-2-7b-chat-hf greedy 2.64E-03 7.96E-03 2.00E-04 4.17E-03 TRUE B3 CPT+SFT Llama-2-7b-chat-hf-CPT-SFT Llama-2-7b-chat-hf-CPT constrained -7.62E-03 2.54E-04 7.10E-02 4.17E-03 FALSE B3 CPT+SFT Llama-2-7b-chat-hf-CPT-SFT Llama-2-7b-chat-hf-CPT greedy -2.69E-02 -1.17E-02 2.00E-04 4.17E-03 TRUE B4 SFT Llama-2-7b-chat-hf-SFT Llama-2-7b-chat-hf constrained 9.28E-03 4.49E-02 2.00E-03 4.17E-03 TRUE INSTRUCT B4 SFT Llama-2-7b-chat-hf-SFT Llama-2-7b-chat-hf greedy 1.54E-01 2.19E-01 2.00E-04 4.17E-03 TRUE C1 CPT meditron-7b-CPT meditron-7b constrained 1.19E-02 2.70E-02 2.00E-04 4.17E-03 TRUE C1 CPT meditron-7b-CPT meditron-7b greedy 4.73E-02 1.05E-01 2.00E-04 4.17E-03 TRUE C2 CPT+SFT meditron-7b-CPT-SFT meditron-7b constrained 3.78E-02 7.33E-02 2.00E-04 4.17E-03 TRUE C2 CPT+SFT meditron-7b-CPT-SFT meditron-7b greedy 6.80E-02 1.47E-01 2.00E-04 4.17E-03 TRUE C3 CPT+SFT meditron-7b-CPT-SFT meditron-7b-CPT constrained 2.20E-02 5.08E-02 2.00E-04 4.17E-03 TRUE C3 CPT+SFT meditron-7b-CPT-SFT meditron-7b-CPT greedy 1.87E-02 4.21E-02 2.00E-04 4.17E-03 TRUE C4 SFT meditron-7b-SFT meditron-7b constrained 3.31E-02 6.48E-02 2.00E-04 4.17E-03 TRUE MEDICAL C4 SFT meditron-7b-SFT meditron-7b greedy 6.23E-02 1.36E-01 2.00E-04 4.17E-03 TRUE D1 SFT LLama-2-7b-hf-SFT Llama-2-7b-chat-hf-SFT constrained -3.69E-02 1.03E-02 4.19E-01 5.56E-03 FALSE D1 SFT LLama-2-7b-hf-SFT Llama-2-7b-chat-hf-SFT greedy -1.22E-01 -6.88E-02 2.00E-04 5.56E-03 TRUE D2 SFT LLama-2-7b-hf-SFT meditron-7b-SFT constrained -1.39E-02 -3.59E-03 2.00E-04 5.56E-03 TRUE D2 SFT LLama-2-7b-hf-SFT meditron-7b-SFT greedy -8.30E-03 1.95E-03 2.48E-01 5.56E-03 FALSE D3 SFT Llama-2-7b-chat-hf-SFT meditron-7b-SFT constrained -1.92E-02 2.74E-02 9.14E-01 5.56E-03 FALSE SFT D3 SFT Llama-2-7b-chat-hf-SFT meditron-7b-SFT greedy 6.34E-02 1.18E-01 2.00E-04 5.56E-03 TRUE E1 CPT Llama-2-7b-hf-CPT Llama-2-7b-chat-hf-CPT constrained -2.48E-02 1.31E-03 8.28E-02 5.56E-03 FALSE E1 CPT Llama-2-7b-hf-CPT Llama-2-7b-chat-hf-CPT greedy -3.69E-03 3.09E-02 1.93E-01 5.56E-03 FALSE E2 CPT Llama-2-7b-hf-CPT meditron-7b-CPT constrained -1.69E-02 -1.09E-03 2.40E-02 5.56E-03 FALSE E2 CPT Llama-2-7b-hf-CPT meditron-7b-CPT greedy -5.63E-02 -2.58E-02 2.00E-04 5.56E-03 TRUE E3 CPT Llama-2-7b-chat-hf-CPT meditron-7b-CPT constrained -6.40E-03 1.11E-02 6.02E-01 5.56E-03 FALSE CPT E3 CPT Llama-2-7b-chat-hf-CPT meditron-7b-CPT greedy -8.45E-02 -2.63E-02 2.00E-04 5.56E-03 TRUE F1 CPT+SFT LLama-2-7b-hf-CPT-SFT Llama-2-7b-chat-hf-CPT-SFT constrained 1.27E-02 3.61E-02 4.00E-04 5.56E-03 TRUE F1 CPT+SFT LLama-2-7b-hf-CPT-SFT Llama-2-7b-chat-hf-CPT-SFT greedy 6.09E-02 1.32E-01 2.00E-04 5.56E-03 TRUE F2 CPT+SFT LLama-2-7b-hf-CPT-SFT meditron-7b-CPT-SFT constrained -1.83E-02 -4.73E-03 1.00E-03 5.56E-03 TRUE F2 CPT+SFT LLama-2-7b-hf-CPT-SFT meditron-7b-CPT-SFT greedy -1.38E-02 -1.53E-03 8.80E-03 5.56E-03 FALSE F3 CPT+SFT Llama-2-7b-chat-hf-CPT-SFT meditron-7b-CPT-SFT constrained -5.07E-02 -2.24E-02 2.00E-04 5.56E-03 TRUE CPT+SFT F3 CPT+SFT Llama-2-7b-chat-hf-CPT-SFT meditron-7b-CPT-SFT greedy -1.44E-01 -6.56E-02 2.00E-04 5.56E-03 TRUE [HTML]CFE2F3Llama 13B A1 CPT Llama-2-13b-hf-CPT Llama-2-13b-hf constrained 2.54E-03 2.02E-02 1.06E-02 4.17E-03 FALSE A1 CPT Llama-2-13b-hf-CPT Llama-2-13b-hf greedy 3.67E-03 1.98E-02 4.40E-03 4.17E-03 FALSE A2 CPT+SFT Llama-2-13b-hf-CPT-SFT Llama-2-13b-hf constrained 2.37E-02 5.45E-02 2.00E-04 4.17E-03 TRUE A2 CPT+SFT Llama-2-13b-hf-CPT-SFT Llama-2-13b-hf greedy 3.27E-02 5.90E-02 2.00E-04 4.17E-03 TRUE A3 CPT+SFT Llama-2-13b-hf-CPT-SFT Llama-2-13b-hf-CPT constrained 1.49E-02 3.87E-02 2.00E-04 4.17E-03 TRUE A3 CPT+SFT Llama-2-13b-hf-CPT-SFT Llama-2-13b-hf-CPT greedy 2.07E-02 4.80E-02 2.00E-04 4.17E-03 TRUE A4 SFT Llama-2-13b-hf-SFT Llama-2-13b-hf constrained 1.81E-02 4.28E-02 2.00E-04 4.17E-03 TRUE GENERAL A4 SFT Llama-2-13b-hf-SFT Llama-2-13b-hf greedy 3.19E-02 5.31E-02 2.00E-04 4.17E-03 TRUE B1 CPT Llama-2-13b-chat-hf-CPT Llama-2-13b-chat-hf constrained -1.18E-03 4.97E-02 6.72E-02 4.17E-03 FALSE B1 CPT Llama-2-13b-chat-hf-CPT Llama-2-13b-chat-hf greedy 1.92E-02 3.14E-02 2.00E-04 4.17E-03 TRUE B2 CPT+SFT Llama-2-13b-chat-hf-CPT-SFT Llama-2-13b-chat-hf constrained 3.87E-02 9.30E-02 2.00E-04 4.17E-03 TRUE B2 CPT+SFT Llama-2-13b-chat-hf-CPT-SFT Llama-2-13b-chat-hf greedy 1.82E-01 2.56E-01 2.00E-04 4.17E-03 TRUE B3 CPT+SFT Llama-2-13b-chat-hf-CPT-SFT Llama-2-13b-chat-hf-CPT constrained 2.54E-02 6.15E-02 2.00E-04 4.17E-03 TRUE B3 CPT+SFT Llama-2-13b-chat-hf-CPT-SFT Llama-2-13b-chat-hf-CPT greedy 1.58E-01 2.31E-01 2.00E-04 4.17E-03 TRUE B4 SFT Llama-2-13b-chat-hf-SFT Llama-2-13b-chat-hf constrained 3.11E-02 8.21E-02 2.00E-04 4.17E-03 TRUE INSTRUCT B4 SFT Llama-2-13b-chat-hf-SFT Llama-2-13b-chat-hf greedy 1.72E-01 2.41E-01 2.00E-04 4.17E-03 TRUE C1 CPT MedLLaMA-13B-CPT MedLLaMA_13B constrained -2.15E-02 1.77E-02 7.73E-01 4.17E-03 FALSE C1 CPT MedLLaMA-13B-CPT MedLLaMA_13B greedy -9.55E-03 2.34E-02 2.68E-01 4.17E-03 FALSE C2 CPT+SFT MedLLaMA-13B-CPT-SFT MedLLaMA_13B constrained 3.11E-02 5.74E-02 2.00E-04 4.17E-03 TRUE C2 CPT+SFT MedLLaMA-13B-CPT-SFT MedLLaMA_13B greedy 3.56E-02 5.96E-02 2.00E-04 4.17E-03 TRUE C3 CPT+SFT MedLLaMA-13B-CPT-SFT MedLLaMA-13B-CPT constrained 2.34E-02 7.11E-02 2.00E-04 4.17E-03 TRUE C3 CPT+SFT MedLLaMA-13B-CPT-SFT MedLLaMA-13B-CPT greedy 1.90E-02 6.57E-02 2.00E-04 4.17E-03 TRUE C4 SFT MedLLaMA-13B-SFT MedLLaMA_13B constrained 2.16E-02 4.90E-02 2.00E-04 4.17E-03 TRUE MEDICAL C4 SFT MedLLaMA-13B-SFT MedLLaMA_13B greedy 2.84E-02 5.80E-02 2.00E-04 4.17E-03 TRUE D1 SFT Llama-2-13b-hf-SFT Llama-2-13b-chat-hf-SFT constrained -4.30E-02 7.32E-03 2.15E-01 5.56E-03 FALSE D1 SFT Llama-2-13b-hf-SFT Llama-2-13b-chat-hf-SFT greedy -1.36E-01 -7.93E-02 2.00E-04 5.56E-03 TRUE D2 SFT Llama-2-13b-hf-SFT MedLLaMA-13B-SFT constrained -3.65E-03 8.03E-03 4.70E-01 5.56E-03 FALSE D2 SFT Llama-2-13b-hf-SFT MedLLaMA-13B-SFT greedy -4.03E-03 7.99E-03 5.32E-01 5.56E-03 FALSE D3 SFT Llama-2-13b-chat-hf-SFT MedLLaMA-13B-SFT constrained -5.69E-03 4.60E-02 1.47E-01 5.56E-03 FALSE SFT D3 SFT Llama-2-13b-chat-hf-SFT MedLLaMA-13B-SFT greedy 7.93E-02 1.41E-01 2.00E-04 5.56E-03 TRUE E1 CPT Llama-2-13b-hf-CPT Llama-2-13b-chat-hf-CPT constrained -1.87E-02 1.02E-02 8.78E-01 5.56E-03 FALSE E1 CPT Llama-2-13b-hf-CPT Llama-2-13b-chat-hf-CPT greedy 2.31E-02 7.61E-02 2.00E-04 5.56E-03 TRUE E2 CPT Llama-2-13b-hf-CPT MedLLaMA-13B-CPT constrained 2.37E-03 3.99E-02 1.16E-02 5.56E-03 FALSE E2 CPT Llama-2-13b-hf-CPT MedLLaMA-13B-CPT greedy -7.36E-03 2.25E-02 7.03E-01 5.56E-03 FALSE E3 CPT Llama-2-13b-chat-hf-CPT MedLLaMA-13B-CPT constrained -5.92E-03 5.27E-02 2.03E-01 5.56E-03 FALSE CPT E3 CPT Llama-2-13b-chat-hf-CPT MedLLaMA-13B-CPT greedy -5.61E-02 -2.58E-02 2.00E-04 5.56E-03 TRUE F1 CPT+SFT Llama-2-13b-hf-CPT-SFT Llama-2-13b-chat-hf-CPT-SFT constrained -4.46E-02 4.48E-03 1.31E-01 5.56E-03 FALSE F1 CPT+SFT Llama-2-13b-hf-CPT-SFT Llama-2-13b-chat-hf-CPT-SFT greedy -1.48E-01 -8.37E-02 2.00E-04 5.56E-03 TRUE F2 CPT+SFT Llama-2-13b-hf-CPT-SFT MedLLaMA-13B-CPT-SFT constrained -6.90E-03 8.26E-03 9.14E-01 5.56E-03 FALSE F2 CPT+SFT Llama-2-13b-hf-CPT-SFT MedLLaMA-13B-CPT-SFT greedy -7.39E-03 6.54E-03 7.66E-01 5.56E-03 FALSE F3 CPT+SFT Llama-2-13b-chat-hf-CPT-SFT MedLLaMA-13B-CPT-SFT constrained -6.57E-03 4.71E-02 1.56E-01 5.56E-03 FALSE CPT+SFT F3 CPT+SFT Llama-2-13b-chat-hf-CPT-SFT MedLLaMA-13B-CPT-SFT greedy 8.45E-02 1.47E-01 2.00E-04 5.56E-03 TRUE Table 8: Significance testing for MCQ/MCQU comparisons. reported separately for greedy and constrained decoding. Each row reports a paired bootstrap test between model_a and model_b. including the 95% confidence interval of the mean EM difference. the two-sided p-value. and the Bonferroni-adjusted threshold with the resulting decision. IDs AâC compare adaptation strategies within the same model type; IDs DâF compare model initializations across types. id strategy model_a model_b ci95_low ci95_high p_two_sided alpha_Bonferoni significant_Bonferroni [HTML]CFE2F3Gemma 4B A1 CPT gemma-3-4b-pt-CPT gemma-3-4b-pt -5.05E-02 3.69E-02 5.14E-01 4.17E-03 FALSE A2 CPT+SFT gemma-3-4b-pt-CPT-SFT gemma-3-4b-pt -2.25E-01 1.65E-01 8.77E-01 4.17E-03 FALSE A3 CPT+SFT gemma-3-4b-pt-CPT-SFT gemma-3-4b-pt-CPT -1.74E-01 1.31E-01 8.73E-01 4.17E-03 FALSE GENERAL A4 SFT gemma-3-4b-pt-SFT gemma-3-4b-pt -2.11E-01 1.41E-01 8.06E-01 4.17E-03 FALSE B1 CPT gemma-3-4b-it-CPT gemma-3-4b-it -4.58E-01 -2.75E-01 2.00E-04 4.17E-03 TRUE B2 CPT+SFT gemma-3-4b-it-CPT-SFT gemma-3-4b-it -4.58E-01 -1.41E-01 2.00E-04 4.17E-03 TRUE B3 CPT+SFT gemma-3-4b-it-CPT-SFT gemma-3-4b-it-CPT -4.94E-03 1.41E-01 6.44E-02 4.17E-03 FALSE INSTRUCT B4 SFT gemma-3-4b-it-SFT gemma-3-4b-it -3.81E-01 -2.06E-01 2.00E-04 4.17E-03 TRUE C1 CPT medgemma-4b-pt-CPT medgemma-4b-pt -3.46E-01 -9.28E-02 2.00E-04 4.17E-03 TRUE C2 CPT+SFT medgemma-4b-pt-CPT-SFT medgemma-4b-pt-CPT 3.71E-02 1.63E-01 2.00E-04 4.17E-03 TRUE C3 CPT+SFT medgemma-4b-pt-CPT-SFT medgemma-4b-pt -2.79E-01 3.51E-02 1.20E-01 4.17E-03 FALSE MEDICAL C4 SFT medgemma-4b-pt-SFT medgemma-4b-pt -1.88E-01 -1.94E-04 3.96E-02 4.17E-03 FALSE D1 SFT gemma-3-4b-pt-SFT gemma-3-4b-it-SFT -3.40E-02 6.17E-02 7.03E-01 5.56E-03 FALSE D2 SFT gemma-3-4b-pt-SFT medgemma-4b-pt-SFT 4.05E-02 9.53E-02 2.00E-04 5.56E-03 TRUE SFT D3 SFT gemma-3-4b-it-SFT medgemma-4b-pt-SFT 2.34E-02 9.61E-02 2.00E-04 5.56E-03 TRUE E1 CPT gemma-3-4b-pt-CPT gemma-3-4b-it-CPT 4.04E-03 2.43E-01 4.24E-02 5.56E-03 FALSE E2 CPT gemma-3-4b-pt-CPT medgemma-4b-pt-CPT 9.44E-02 4.14E-01 2.00E-04 5.56E-03 TRUE CPT E3 CPT gemma-3-4b-it-CPT medgemma-4b-pt-CPT 6.99E-02 1.63E-01 2.00E-04 5.56E-03 TRUE F1 CPT+SFT gemma-3-4b-pt-CPT-SFT gemma-3-4b-it-CPT-SFT 5.49E-03 7.53E-02 6.80E-03 5.56E-03 FALSE F2 CPT+SFT gemma-3-4b-pt-CPT-SFT medgemma-4b-pt-CPT-SFT 7.33E-02 1.95E-01 2.00E-04 5.56E-03 TRUE CPT+SFT F3 CPT+SFT gemma-3-4b-it-CPT-SFT medgemma-4b-pt-CPT-SFT 3.56E-02 1.55E-01 2.00E-04 5.56E-03 TRUE [HTML]CFE2F3Mistral 7B A1 CPT Mistral-7B-v0.1-CPT Mistral-7B-v0.1 -1.74E-01 5.41E-02 6.35E-01 4.17E-03 FALSE A2 CPT+SFT Mistral-7B-v0.1-CPT-SFT Mistral-7B-v0.1 -2.09E-01 1.37E-01 8.37E-01 4.17E-03 FALSE A3 CPT+SFT Mistral-7B-v0.1-CPT-SFT Mistral-7B-v0.1-CPT -8.42E-02 9.06E-02 9.22E-01 4.17E-03 FALSE GENERAL A4 SFT Mistral-7B-v0.1-SFT Mistral-7B-v0.1 -2.32E-01 1.02E-01 6.17E-01 4.17E-03 FALSE B1 CPT Mistral-7B-Instruct-v0.1-CPT Mistral-7B-Instruct-v0.1 -4.68E-02 1.69E-01 1.48E-01 4.17E-03 FALSE B2 CPT+SFT Mistral-7B-Instruct-v0.1-CPT-SFT Mistral-7B-Instruct-v0.1-CPT -7.19E-02 -3.74E-02 2.00E-04 4.17E-03 TRUE B3 CPT+SFT Mistral-7B-Instruct-v0.1-CPT-SFT Mistral-7B-Instruct-v0.1 -1.15E-01 1.34E-01 7.76E-01 4.17E-03 FALSE INSTRUCT B4 SFT Mistral-7B-Instruct-v0.1-SFT Mistral-7B-Instruct-v0.1 -2.64E-01 1.30E-02 1.29E-01 4.17E-03 FALSE C1 CPT BioMistral-7B-CPT BioMistral-7B -1.74E-01 7.18E-02 6.52E-01 4.17E-03 FALSE C2 CPT+SFT BioMistral-7B-CPT-SFT BioMistral-7B -3.40E-02 1.03E-01 2.42E-01 4.17E-03 FALSE C3 CPT+SFT BioMistral-7B-CPT-SFT BioMistral-7B-CPT 1.04E-02 1.31E-01 9.00E-03 4.17E-03 FALSE MEDICAL C4 SFT BioMistral-7B-SFT BioMistral-7B -1.41E-01 4.33E-02 4.24E-01 4.17E-03 FALSE D1 SFT Mistral-7B-v0.1-SFT Mistral-7B-Instruct-v0.1-SFT 2.14E-02 9.83E-02 2.00E-04 5.56E-03 TRUE D2 SFT Mistral-7B-Instruct-v0.1-SFT BioMistral-7B-SFT -3.04E-02 4.71E-02 7.02E-01 5.56E-03 FALSE SFT D3 SFT Mistral-7B-v0.1-SFT BioMistral-7B-SFT 4.48E-02 7.93E-02 2.00E-04 5.56E-03 TRUE E1 CPT Mistral-7B-v0.1-CPT Mistral-7B-Instruct-v0.1-CPT -1.51E-01 -9.28E-02 2.00E-04 5.56E-03 TRUE E2 CPT Mistral-7B-v0.1-CPT BioMistral-7B-CPT -2.97E-02 1.67E-01 2.44E-01 5.56E-03 FALSE CPT E3 CPT Mistral-7B-Instruct-v0.1-CPT BioMistral-7B-CPT 1.02E-01 3.12E-01 2.00E-04 5.56E-03 TRUE F1 CPT+SFT Mistral-7B-v0.1-CPT-SFT Mistral-7B-Instruct-v0.1-CPT-SFT -1.25E-01 -1.04E-02 7.40E-03 5.56E-03 FALSE F2 CPT+SFT Mistral-7B-v0.1-CPT-SFT BioMistral-7B-CPT-SFT -2.23E-02 3.51E-02 8.31E-01 5.56E-03 FALSE CPT+SFT F3 CPT+SFT Mistral-7B-Instruct-v0.1-CPT-SFT BioMistral-7B-CPT-SFT 4.40E-02 1.07E-01 2.00E-04 5.56E-03 TRUE [HTML]CFE2F3LLAMA-7 FAMILY A1 CPT Llama-2-7b-hf-CPT Llama-2-7b-hf -1.17E-01 2.53E-03 7.46E-02 4.17E-03 FALSE A2 CPT+SFT LLama-2-7b-hf-CPT-SFT Llama-2-7b-hf-CPT 4.46E-02 1.40E-01 2.00E-04 4.17E-03 TRUE A3 CPT+SFT LLama-2-7b-hf-CPT-SFT Llama-2-7b-hf -5.92E-02 9.36E-02 5.18E-01 4.17E-03 FALSE GENERAL A4 SFT LLama-2-7b-hf-SFT Llama-2-7b-hf -9.58E-02 5.00E-02 8.01E-01 4.17E-03 FALSE B1 CPT Llama-2-7b-chat-hf-CPT Llama-2-7b-chat-hf -1.05E-01 7.92E-02 7.39E-01 4.17E-03 FALSE B2 CPT+SFT Llama-2-7b-chat-hf-CPT-SFT Llama-2-7b-chat-hf -4.91E-02 7.67E-02 4.88E-01 4.17E-03 FALSE B3 CPT+SFT Llama-2-7b-chat-hf-CPT-SFT Llama-2-7b-chat-hf-CPT -3.13E-02 6.42E-02 3.87E-01 4.17E-03 FALSE INSTRUCT B4 SFT Llama-2-7b-chat-hf-SFT Llama-2-7b-chat-hf -2.67E-01 2.10E-03 8.08E-02 4.17E-03 FALSE C1 CPT meditron-7b-CPT meditron-7b -8.36E-03 1.95E-02 4.18E-01 4.17E-03 FALSE C2 CPT+SFT meditron-7b-CPT-SFT meditron-7b 3.69E-03 9.40E-02 4.08E-02 4.17E-03 FALSE C3 CPT+SFT meditron-7b-CPT-SFT meditron-7b-CPT -1.49E-02 9.99E-02 1.30E-01 4.17E-03 FALSE MEDICAL C4 SFT meditron-7b-SFT meditron-7b -9.43E-02 3.43E-02 4.08E-01 4.17E-03 FALSE D1 SFT LLama-2-7b-hf-SFT Llama-2-7b-chat-hf-SFT -9.81E-02 -2.37E-02 2.00E-04 5.56E-03 TRUE D2 SFT LLama-2-7b-hf-SFT meditron-7b-SFT -3.18E-02 -4.98E-03 7.80E-03 5.56E-03 FALSE SFT D3 SFT Llama-2-7b-chat-hf-SFT meditron-7b-SFT -4.93E-03 8.30E-02 1.49E-01 5.56E-03 FALSE E1 CPT Llama-2-7b-hf-CPT Llama-2-7b-chat-hf-CPT -2.96E-01 -1.31E-01 2.00E-04 5.56E-03 TRUE E2 CPT Llama-2-7b-hf-CPT meditron-7b-CPT -1.37E-01 -3.73E-02 2.00E-04 5.56E-03 TRUE CPT E3 CPT Llama-2-7b-chat-hf-CPT meditron-7b-CPT 8.64E-02 1.72E-01 2.00E-04 5.56E-03 TRUE F1 CPT+SFT LLama-2-7b-hf-CPT-SFT Llama-2-7b-chat-hf-CPT-SFT -2.83E-01 -5.47E-02 2.00E-04 5.56E-03 TRUE F2 CPT+SFT LLama-2-7b-hf-CPT-SFT meditron-7b-CPT-SFT -7.39E-02 -3.20E-02 2.00E-04 5.56E-03 TRUE CPT+SFT F3 CPT+SFT Llama-2-7b-chat-hf-CPT-SFT meditron-7b-CPT-SFT 6.85E-03 2.06E-01 7.00E-03 5.56E-03 FALSE [HTML]CFE2F3Llama 13B A1 CPT Llama-2-13b-hf-CPT Llama-2-13b-hf -9.64E-02 -2.62E-02 2.00E-04 4.17E-03 TRUE A2 CPT+SFT Llama-2-13b-hf-CPT-SFT Llama-2-13b-hf -1.25E-02 1.84E-01 1.19E-01 4.17E-03 FALSE A3 CPT+SFT Llama-2-13b-hf-CPT-SFT Llama-2-13b-hf-CPT 6.32E-02 2.31E-01 2.00E-04 4.17E-03 TRUE GENERAL A4 SFT Llama-2-13b-hf-SFT Llama-2-13b-hf -3.35E-02 9.53E-02 4.87E-01 4.17E-03 FALSE B1 CPT Llama-2-13b-chat-hf-CPT Llama-2-13b-chat-hf -1.03E-02 1.32E-01 1.44E-01 4.17E-03 FALSE B2 CPT+SFT Llama-2-13b-chat-hf-CPT-SFT Llama-2-13b-chat-hf -3.25E-01 6.12E-02 4.22E-01 4.17E-03 FALSE B3 CPT+SFT Llama-2-13b-chat-hf-CPT-SFT Llama-2-13b-chat-hf-CPT -3.19E-01 -6.80E-02 2.00E-04 4.17E-03 TRUE INSTRUCT B4 SFT Llama-2-13b-chat-hf-SFT Llama-2-13b-chat-hf -3.78E-01 -4.44E-03 4.28E-02 4.17E-03 FALSE C1 CPT MedLLaMA-13B-CPT MedLLaMA_13B 8.59E-03 3.82E-02 9.60E-03 4.17E-03 FALSE C2 CPT+SFT MedLLaMA-13B-CPT-SFT MedLLaMA_13B -7.65E-03 1.81E-01 1.50E-01 4.17E-03 FALSE C3 CPT+SFT MedLLaMA-13B-CPT-SFT MedLLaMA-13B-CPT -2.00E-02 1.43E-01 1.48E-01 4.17E-03 FALSE MEDICAL C4 SFT MedLLaMA-13B-SFT MedLLaMA_13B -4.70E-02 9.93E-02 3.78E-01 4.17E-03 FALSE D1 SFT Llama-2-13b-hf-SFT Llama-2-13b-chat-hf-SFT 5.63E-03 5.57E-02 2.00E-04 5.56E-03 TRUE D2 SFT Llama-2-13b-hf-SFT MedLLaMA-13B-SFT -2.49E-02 4.98E-02 6.34E-01 5.56E-03 FALSE SFT D3 SFT Llama-2-13b-chat-hf-SFT MedLLaMA-13B-SFT -7.22E-02 1.13E-02 6.27E-01 5.56E-03 FALSE E1 CPT Llama-2-13b-hf-CPT Llama-2-13b-chat-hf-CPT -4.04E-01 -2.38E-01 2.00E-04 5.56E-03 TRUE E2 CPT Llama-2-13b-hf-CPT MedLLaMA-13B-CPT -9.08E-02 -6.25E-02 2.00E-04 5.56E-03 TRUE CPT E3 CPT Llama-2-13b-chat-hf-CPT MedLLaMA-13B-CPT 1.63E-01 3.21E-01 2.00E-04 5.56E-03 TRUE F1 CPT+SFT Llama-2-13b-hf-CPT-SFT Llama-2-13b-chat-hf-CPT-SFT -4.38E-02 4.50E-02 8.76E-01 5.56E-03 FALSE F2 CPT+SFT Llama-2-13b-hf-CPT-SFT MedLLaMA-13B-CPT-SFT -2.24E-02 3.90E-02 5.73E-01 5.56E-03 FALSE CPT+SFT F3 CPT+SFT Llama-2-13b-chat-hf-CPT-SFT MedLLaMA-13B-CPT-SFT -1.39E-02 2.73E-02 5.62E-01 5.56E-03 FALSE Table 9: Significance testing for OEQA comparisons. Each row reports a paired bootstrap test between model_a and model_b, including the 95% confidence interval of the mean difference (ci95_low, ci95_high), the two-sided p-value, and the Bonferroni-adjusted threshold (alpha_Bonferoni) with the resulting decision (significant_Bonferroni). IDs AâC compare adaptation strategies within the same model type; IDs DâF compare model initializations across types. We assess whether observed differences between adaptation strategies and initialization choices are statistically significant using paired bootstrap significance testing. For each comparison, we compute the per-instance score difference (EM for MCQ/MCQU; judge-based correctness for OEQA) and report a two-sided p-value (p_two_sided). Statistical significance is determined by comparing this p-value against a predefined threshold α. We report results using a Bonferroni-corrected threshold to control for multiple comparisons. For comparisons between adaptation strategies within a model family, we perform 12 pairwise tests per family, yielding a corrected threshold of αBonferroni=0.05/12 _Bonferroni=0.05/12. For comparisons between model initialization types under a fixed adaptation strategy, we perform 9 pairwise tests per family, yielding αBonferroni=0.05/9 _Bonferroni=0.05/9. The applied threshold (alpha_Bonferoni) and the resulting significance decision (significant_Bonferroni) are reported explicitly in Tables 8 and 9. We define the mean difference as Î=scoreâ(model_a)âscoreâ(model_b) =score( model\_a)-score( model\_b) (not shown in the tables). Therefore, if the confidence interval is entirely above zero, model_a performs better; if it is entirely below zero, model_b performs better. A comparison is considered statistically significant if the corrected decision is TRUE. J.1 Interpretation of comparison IDs Each row in Tables 8 and 9 corresponds to a specific pairwise comparison between two models (model_a vs. model_b). The id field encodes the purpose of the comparison: (i) IDs AâC compare models within the same model type (GENERAL, INSTRUCT, or MEDICAL) in order to quantify the effect of adaptation strategies (CPT, SFT, CPT+SFT) relative to a fixed initialization. (i) IDs DâF compare models across model types under a fixed adaptation strategy, in order to identify the most effective initialization point (GENERAL vs. INSTRUCT vs. MEDICAL) for downstream adaptation. J.2 Decoding conditions For MCQ/MCQU, Table 8 reports significance results separately for greedy and constrained decoding. For OEQA, Table 9 reports strategy-level comparisons under the evaluation setting used for the main experiments. Appendix K Near-Miss Rates in MCQA Model MCQ MCQU Mistral 0.203 0.202 Mistral-CPT 0.212 0.203 Mistral-SFT 0.234 0.204 Mistral-CPT-SFT 0.256 0.203 Mistral-Instruct 0.173 0.202 Mistral-Instruct-CPT 0.205 0.202 Mistral-Instruct-SFT 0.174 0.206 Mistral-Instruct-CPT-SFT 0.221 0.192 BioMistral 0.181 0.205 BioMistral-CPT 0.195 0.201 BioMistral-SFT 0.220 0.211 BioMistral-CPT-SFT 0.234 0.204 Table 10: Near-miss rates for MCQ and MCQU across Mistral variants. A near-miss corresponds to cases where all gold answers are ranked within the top-k options but the generated answer does not match the gold label(s). Near-miss rates remain stable across model families and adaptation strategies, indicating that improvements in confidence and ranking do not directly translate into exact prediction. To better characterize model behavior beyond EM accuracy in MCQA, we analyze near-miss predictions. Table 10 shows the near-miss rates obtained for MCQ and MCQU across different Mistral-based model variants and adaptation strategies. Appendix L OEQA Evaluation: Verbosity Bias Model Type Strategy mean_words std_words median_words mean_chars std_chars median_chars [HTML]CFE2F3Gemma-4B Base 243,30 123,00 288,00 1 616,51 798,74 1,927,00 CPT 107,81 122,82 37,00 720,79 806,61 245,00 SFT 176,70 127,77 204,00 1 182,16 877,20 1 153,00 GENERAL CPT+SFT 279,84 87,77 300,00 1 884,34 649,64 2 076,00 Base 261,62 67,98 282,00 1 819,58 473,70 1 985,00 CPT 266,87 98,66 286,00 1 763,62 576,08 1 878,00 SFT 243,03 65,58 261,00 3 513,80 827,10 3 326,00 INSTRUCT CPT+SFT 183,16 98,86 207,00 3 497,45 1 680,82 2 632,00 Base 208,62 122,41 205,00 1 371,82 793,35 1 431,00 CPT 216,10 142,15 264,00 1 308,81 861,75 1 661,00 SFT 271,22 97,47 292,00 1 796,17 705,16 1 982,00 MEDICAL CPT+SFT 282,47 48,88 283,00 1 825,36 519,84 1 954,00 [HTML]CFE2F3Mistral-7B Base 212,56 58,84 224,00 1 466,40 329,83 1 502,00 CPT 173,15 84,30 193,00 1 102,15 536,40 1,321,50 SFT 130,36 90,43 138,00 884,67 603,37 906,00 GENERAL CPT+SFT 226,60 31,85 229,00 1 508,78 236,78 1 527,00 Base 134,18 74,11 125,00 876,12 476,77 812,00 CPT 67,79 75,91 37,00 447,32 481,36 244,00 SFT 19,59 14,19 19,00 138,75 100,30 136,00 INSTRUCT CPT+SFT 168,09 77,91 199,00 1 112,24 499,35 1 314,00 Base 66,26 76,56 37,00 443,89 500,84 250,00 CPT 99,03 102,06 41,00 651,69 650,72 279,00 SFT 128,83 98,75 159,00 855,12 657,31 950,00 MEDICAL CPT+SFT 132,20 91,72 129,00 909,46 619,60 859,00 [HTML]CFE2F3Llama-7B Base 206,13 67,03 222,00 1 358,82 392,59 1 459,00 CPT 41,99 78,06 8,00 269,34 490,77 56,00 SFT 219,26 35,68 220,00 1 399,00 266,52 1 441,00 GENERAL CPT+SFT 217,98 50,08 224,00 1 376,29 353,15 1 442,00 Base 233,79 66,58 244,00 1 513,45 433,69 1 586,00 CPT 72,29 87,21 26,00 483,67 572,37 180,00 SFT 18,24 14,33 18,00 126,03 93,60 127,00 INSTRUCT CPT+SFT 123,65 86,95 106,00 859,20 581,43 784,00 Base 227,34 40,78 230,00 1 498,30 211,08 1 522,50 CPT 130,92 104,72 128,00 847,07 671,76 1 008,00 SFT 204,04 40,98 209,00 1 350,16 345,45 1 431,00 MEDICAL CPT+SFT 216,96 38,84 220,00 1 416,50 301,18 1 466,00 [HTML]CFE2F3Llama-13B Base 168,15 44,63 146,00 1 144,75 260,69 1 020,00 CPT 26,19 53,89 9,00 173,89 351,27 58,00 SFT 218,99 36,11 219,00 1 440,23 300,92 1 523,00 GENERAL CPT+SFT 225,12 36,23 228,00 1 429,25 280,81 1 482,00 Base 226,32 60,72 235,00 1 471,46 396,55 1 529,00 CPT 79,32 80,61 45,00 528,55 526,68 303,00 SFT 17,34 10,39 18,00 121,18 74,56 129,00 INSTRUCT CPT+SFT 19,79 17,18 19,00 141,49 132,88 136,00 Base 217,49 47,81 221,00 1 429,19 269,92 1 459,00 CPT 65,17 92,92 13,00 431,03 597,64 92,00 SFT 206,21 53,97 219,00 1 394,11 392,06 1 505,00 MEDICAL CPT+SFT 215,44 37,48 220,00 1 351,46 345,39 1 402,50 Table 11: Output length statistics for OEQA generations across model families, initialization types (GENERAL/INSTRUCT/MEDICAL), and adaptation strategies (Base, CPT, SFT, CPT+SFT). We report the mean, standard deviation, and median number of words and characters per generated answer. Bold values highlight, within each block, the maximum value for the corresponding statistic. To investigate verbosity bias in OEQA, we compute descriptive statistics of generated answer lengths across all models. Table 11 reports mean, median, and standard deviation of word and character counts over greedy OEQA outputs. Appendix M English vs. French Benchmarks: Full Numeric Results MCQU-FR MCQU-EN Greedy Constrained Greedy Constrained Model Type Strategy EM EM [HTML]CFE2F3Gemma-4B Base 5.76 26.63 1.60 41.22 CPT 8.54 25.60 12.77 40.10 SFT 19.92 32.82 51.60 51.60 GENERAL CPT+SFT 19.55 32.73 51.42 51.42 Base 29.38 29.76 47.89 47.94 CPT 1.36 24.28 1.39 23.43 SFT 32.38 32.46 48.74 48.74 INSTRUCT CPT+SFT 30.31 30.38 39.17 39.17 Base 11.50 26.43 0.04 32.47 CPT 10.94 24.71 7.64 23.85 SFT 17.81 30.77 45.03 45.03 MEDICAL CPT+SFT 17.41 30.50 40.14 40.14 [HTML]CFE2F3Mistral-7B Base 4.51 28.96 1.34 26.15 CPT 13.84 27.15 6.00 25.20 SFT 19.88 32.98 7.77 27.00 GENERAL CPT+SFT 19.47 32.22 9.58 27.39 Base 21.58 25.51 5.96 25.10 CPT 28.65 29.69 6.90 25.51 SFT 31.64 31.74 7.18 26.38 INSTRUCT CPT+SFT 29.94 30.11 6.75 25.21 Base 13.52 26.88 5.45 25.69 CPT 12.10 25.49 6.05 24.32 SFT 18.45 31.64 7.10 26.28 MEDICAL CPT+SFT 19.30 32.33 7.43 26.90 [HTML]CFE2F3Llama-7B Base 9.38 25.48 3.46 25.17 CPT 6.00 25.27 21.14 28.56 SFT 15.74 28.61 32.86 32.87 GENERAL CPT+SFT 16.97 29.77 39.25 39.25 Base 0.00 24.34 0.00 23.44 CPT 0.00 24.29 0.00 23.49 SFT 29.52 29.58 38.73 38.73 INSTRUCT CPT+SFT 0.00 24.54 0.00 23.45 Base 0.35 24.19 0.98 23.68 CPT 11.97 25.14 0.09 24.96 SFT 17.38 30.27 36.80 36.80 MEDICAL CPT+SFT 18.29 31.60 36.53 36.53 [HTML]CFE2F3Llama-13B Base 11.20 25.51 16.55 34.83 CPT 10.68 26.64 29.79 37.21 SFT 17.30 30.18 43.22 43.22 GENERAL CPT+SFT 18.27 31.41 43.62 43.62 Base 0.00 21.68 0.00 23.60 CPT 0.00 24.57 0.00 24.85 SFT 30.04 30.10 46.99 46.99 INSTRUCT CPT+SFT 31.42 31.51 46.57 46.57 Base 10.31 23.97 12.48 24.28 CPT 10.22 23.37 10.01 30.87 SFT 16.73 29.88 37.71 37.71 MEDICAL CPT+SFT 18.24 31.32 42.73 42.73 Table 12: Cross-lingual comparison between native English MCQU benchmarks (MCQU-EN) and their French translations (MCQU-FR), reported as EM (%). Results are shown for both greedy and constrained decoding. For each row and decoding type, bold values indicate the higher EM between MCQU-FR and MCQU-EN. The main paper reports averaged results using constrained decoding (Figure 2). Table 12 provides the complete numeric EM results for both greedy and constrained decoding on the native English MCQU benchmarks (MCQU-EN) and their French translations (MCQU-FR). M.1 Greedy decoding analysis The greedy decoding results reported in Table 12 exhibit the same overall tendencies as those observed under constrained decoding in section 5. For the Mistral family, greedy decoding consistently yields higher performance on the French translations than on the original English benchmarks, both before and after adaptation. Conversely, Gemma and Llama models generally perform better on native English benchmarks under greedy decoding, and this advantage is preserved after French medical adaptation. As with constrained decoding, adaptation on French medical data improves performance in both languages under greedy decoding, indicating effective cross-lingual transfer. While absolute EM scores differ between decoding strategies, greedy decoding generally producing lower scores, the relative ordering between English and French benchmarks and the direction of adaptation effects remain consistent. These results suggest that the cross-lingual patterns reported in the main paper are robust to the choice of decoding strategy. M.2 Significance testing (English vs. French) To assess whether the EnglishâFrench performance gaps are statistically significant, we perform paired significance testing separately for each model configuration, i.e., for each combination of (model family/type, adaptation strategy, decoding type). For each configuration, we compute the per-item EM difference between MCQU-EN and MCQU-FR on matched translated instances, and estimate a 95% confidence interval for the mean difference together with a two-sided p-value. Because each test compares a model strictly with itself across languages and each EnglishâFrench pair is independent of the others, we do not apply a Bonferroni correction. Table 13 reports the resulting confidence intervals and significance decisions. Model Type Strategy Model Decoding Type ci95_low ci95_high p_two_sided Significant [HTML]CFE2F3Gemma-4B Base gemma-3-4b-pt greedy 2,57E-02 6,42E-02 2,00E-04 TRUE Base gemma-3-4b-pt constrained -1,97E-01 -9,55E-02 2,00E-04 TRUE CPT gemma-3-4b-pt-CPT greedy -6,57E-02 -1,71E-02 2,20E-03 TRUE CPT gemma-3-4b-pt-CPT constrained -1,86E-01 -1,01E-01 2,00E-04 TRUE CPT+SFT gemma-3-4b-CPT-SFT greedy -4,01E-01 -2,18E-01 2,00E-04 TRUE CPT+SFT gemma-3-4b-CPT-SFT constrained -2,48E-01 -1,14E-01 2,00E-04 TRUE SFT gemma-3-4b-pt-SFT greedy -3,98E-01 -2,19E-01 2,00E-04 TRUE GENERAL SFT gemma-3-4b-pt-SFT constrained -2,50E-01 -1,17E-01 2,00E-04 TRUE Base gemma-3-4b-it greedy -2,31E-01 -1,36E-01 2,00E-04 TRUE Base gemma-3-4b-it constrained -2,27E-01 -1,33E-01 2,00E-04 TRUE CPT gemma-3-4b-it-CPT greedy -8,82E-03 7,42E-03 9,70E-01 FALSE CPT gemma-3-4b-it-CPT constrained -1,89E-02 4,55E-02 6,71E-01 FALSE CPT+SFT gemma-3-4b-it-CPT-SFT greedy -1,14E-01 -6,32E-02 2,00E-04 TRUE CPT+SFT gemma-3-4b-it-CPT-SFT constrained -1,14E-01 -6,21E-02 2,00E-04 TRUE SFT gemma-3-4b-it-SFT greedy -2,22E-01 -9,37E-02 2,00E-04 TRUE INSTRUCT SFT gemma-3-4b-it-SFT constrained -2,20E-01 -9,53E-02 2,00E-04 TRUE Base medgemma-4b-pt greedy 6,05E-02 2,00E-01 2,00E-04 TRUE Base medgemma-4b-pt constrained -1,05E-01 -6,63E-03 2,94E-02 TRUE CPT medgemma-4b-pt-CPT greedy -8,53E-03 9,14E-02 1,71E-01 FALSE CPT medgemma-4b-pt-CPT constrained -1,45E-02 4,11E-02 6,29E-01 FALSE CPT+SFT medgemma-4b-pt-CPT-SFT greedy -2,92E-01 -1,50E-01 2,00E-04 TRUE CPT+SFT medgemma-4b-pt-CPT-SFT constrained -1,39E-01 -4,81E-02 4,00E-04 TRUE SFT medgemma-4b-pt-SFT greedy -3,43E-01 -1,90E-01 2,00E-04 TRUE MEDICAL SFT medgemma-4b-pt-SFT constrained -1,93E-01 -8,67E-02 2,00E-04 TRUE [HTML]CFE2F3Mistral-7B Base Mistral-7B-v0.1 greedy -1,62E-02 1,20E-01 6,98E-01 FALSE Base Mistral-7B-v0.1 constrained 8,39E-02 1,70E-01 2,00E-04 TRUE CPT Mistral-7B-v0.1-CPT greedy 3,64E-02 1,48E-01 2,00E-04 TRUE CPT Mistral-7B-v0.1-CPT constrained 7,59E-02 1,43E-01 2,00E-04 TRUE CPT+SFT Mistral-7B-v0.1-CPT-SFT greedy 5,94E-02 1,61E-01 2,00E-04 TRUE CPT+SFT Mistral-7B-v0.1-CPT-SFT constrained 4,90E-02 1,04E-01 2,00E-04 TRUE SFT Mistral-7B-v0.1-SFT greedy 7,77E-02 1,92E-01 2,00E-04 TRUE GENERAL SFT Mistral-7B-v0.1-SFT constrained 5,74E-02 1,29E-01 2,00E-04 TRUE Base Mistral-7B-Instruct-v0.1 greedy 1,30E-01 1,83E-01 2,00E-04 TRUE Base Mistral-7B-Instruct-v0.1 constrained 1,21E-01 1,60E-01 2,00E-04 TRUE CPT Mistral-7B-Instruct-v0.1-CPT greedy 1,74E-01 2,62E-01 2,00E-04 TRUE CPT Mistral-7B-Instruct-v0.1-CPT constrained 9,71E-02 1,73E-01 2,00E-04 TRUE CPT+SFT Mistral-7B-Instruct-v0.1-CPT-SFT greedy 1,83E-01 2,94E-01 2,00E-04 TRUE CPT+SFT Mistral-7B-Instruct-v0.1-CPT-SFT constrained 6,43E-02 1,42E-01 2,00E-04 TRUE SFT Mistral-7B-Instruct-v0.1-SFT greedy 1,92E-01 3,03E-01 2,00E-04 TRUE INSTRUCT SFT Mistral-7B-Instruct-v0.1-SFT constrained 7,81E-02 1,56E-01 2,00E-04 TRUE Base BioMistral-7B greedy 4,88E-02 1,29E-01 2,00E-04 TRUE Base BioMistral-7B constrained 1,21E-01 1,63E-01 2,00E-04 TRUE CPT BioMistral-7B-CPT greedy 3,47E-02 9,30E-02 2,00E-04 TRUE CPT BioMistral-7B-CPT constrained 9,18E-02 1,20E-01 2,00E-04 TRUE CPT+SFT BioMistral-7B-CPT-SFT greedy 6,82E-02 2,06E-01 2,00E-04 TRUE CPT+SFT BioMistral-7B-CPT-SFT constrained 8,89E-02 1,88E-01 2,00E-04 TRUE SFT BioMistral-7B-SFT greedy 6,71E-02 1,94E-01 2,00E-04 TRUE MEDICAL SFT BioMistral-7B-SFT constrained 8,33E-02 1,68E-01 2,00E-04 TRUE [HTML]CFE2F3Llama-7B Base Llama-2-7b-hf greedy 1,22E-02 1,24E-01 6,60E-03 TRUE Base Llama-2-7b-hf constrained -2,49E-02 3,53E-02 8,46E-01 FALSE CPT Llama-2-7b-hf-CPT greedy -2,23E-01 -6,14E-02 4,00E-03 TRUE CPT Llama-2-7b-hf-CPT constrained -2,27E-02 1,19E-01 3,12E-01 FALSE CPT+SFT LLama-2-7b-hf-CPT-SFT greedy -2,93E-01 -1,33E-01 2,00E-04 TRUE CPT+SFT LLama-2-7b-hf-CPT-SFT constrained -1,49E-01 -3,08E-02 4,20E-03 TRUE SFT LLama-2-7b-hf-SFT greedy -2,27E-01 -9,34E-02 4,00E-04 TRUE GENERAL SFT LLama-2-7b-hf-SFT constrained -8,38E-02 7,10E-03 8,72E-02 FALSE Base Llama-2-7b-chat-hf greedy 0,00E+00 0,00E+00 1,00E+00 FALSE Base Llama-2-7b-chat-hf constrained 1,84E-01 3,09E-01 2,00E-04 TRUE CPT Llama-2-7b-chat-hf-CPT greedy 0,00E+00 1,02E-04 7,23E-01 FALSE CPT Llama-2-7b-chat-hf-CPT constrained 5,27E-02 2,03E-01 2,00E-04 TRUE CPT+SFT Llama-2-7b-chat-hf-CPT-SFT greedy 0,00E+00 6,80E-05 7,01E-01 FALSE CPT+SFT Llama-2-7b-chat-hf-CPT-SFT constrained 8,66E-02 1,40E-01 2,00E-04 TRUE SFT Llama-2-7b-chat-hf-SFT greedy -1,32E-01 -3,94E-02 1,20E-03 TRUE INSTRUCT SFT Llama-2-7b-chat-hf-SFT constrained -1,31E-01 -3,80E-02 1,20E-03 TRUE Base meditron-7b greedy -1,03E-02 -2,51E-03 1,00E-03 TRUE Base meditron-7b constrained -1,42E-02 3,19E-02 5,00E-01 FALSE CPT meditron-7b-CPT greedy -6,55E-03 1,08E-01 3,98E-01 FALSE CPT meditron-7b-CPT constrained 2,15E-03 6,87E-02 3,58E-02 TRUE CPT+SFT meditron-7b-CPT-SFT greedy -2,61E-01 -7,38E-02 1,80E-03 TRUE CPT+SFT meditron-7b-CPT-SFT constrained -1,05E-01 2,86E-02 1,86E-01 FALSE SFT meditron-7b-SFT greedy -2,64E-01 -1,02E-01 2,00E-04 TRUE MEDICAL SFT meditron-7b-SFT constrained -1,15E-01 -3,59E-03 4,00E-02 TRUE [HTML]CFE2F3Llama-13B Base Llama-2-13b-hf greedy -1,31E-01 5,40E-02 2,74E-01 FALSE Base Llama-2-13b-hf constrained -1,35E-01 -4,79E-02 4,00E-04 TRUE CPT Llama-2-13b-hf-CPT greedy -2,65E-01 -1,00E-01 2,00E-04 TRUE CPT Llama-2-13b-hf-CPT constrained -1,09E-01 2,30E-02 1,58E-01 FALSE CPT+SFT Llama-2-13b-hf-CPT-SFT greedy -3,31E-01 -1,52E-01 2,00E-04 TRUE CPT+SFT Llama-2-13b-hf-CPT-SFT constrained -1,82E-01 -5,08E-02 1,60E-03 TRUE SFT Llama-2-13b-hf-SFT greedy -3,30E-01 -1,68E-01 2,00E-04 TRUE GENERAL SFT Llama-2-13b-hf-SFT constrained -1,87E-01 -6,61E-02 2,00E-04 TRUE Base Llama-2-13b-chat-hf greedy 0,00E+00 0,00E+00 1,00E+00 FALSE Base Llama-2-13b-chat-hf constrained -4,79E-02 2,61E-03 1,06E-01 FALSE CPT Llama-2-13b-chat-hf-CPT greedy 0,00E+00 0,00E+00 1,00E+00 FALSE CPT Llama-2-13b-chat-hf-CPT constrained -2,29E-02 2,51E-02 7,65E-01 FALSE CPT+SFT Llama-2-13b-chat-hf-CPT-SFT greedy -2,09E-01 -7,94E-02 4,00E-04 TRUE CPT+SFT Llama-2-13b-chat-hf-CPT-SFT constrained -2,06E-01 -7,95E-02 2,00E-04 TRUE SFT Llama-2-13b-chat-hf-SFT greedy -2,21E-01 -1,15E-01 2,00E-04 TRUE INSTRUCT SFT Llama-2-13b-chat-hf-SFT constrained -2,20E-01 -1,16E-01 2,00E-04 TRUE Base MedLLaMA_13B greedy -8,31E-02 4,03E-02 4,90E-01 FALSE Base MedLLaMA_13B constrained -2,46E-02 1,98E-02 7,65E-01 FALSE CPT MedLLaMA-13B-CPT greedy -3,43E-02 3,73E-02 8,95E-01 FALSE CPT MedLLaMA-13B-CPT constrained -1,10E-01 -4,51E-02 2,00E-04 TRUE CPT+SFT MedLLaMA-13B-CPT-SFT greedy -3,14E-01 -1,60E-01 2,00E-04 TRUE CPT+SFT MedLLaMA-13B-CPT-SFT constrained -1,68E-01 -5,56E-02 1,40E-03 TRUE SFT MedLLaMA-13B-SFT greedy -2,76E-01 -1,29E-01 2,00E-04 TRUE MEDICAL SFT MedLLaMA-13B-SFT constrained -1,27E-01 -2,23E-02 7,20E-03 TRUE Table 13: Paired significance testing between MCQU-EN and MCQU-FR for each model configuration (model, strategy, and decoding type). Reported values are the 95% confidence interval of the mean EM difference and the corresponding two-sided two-sided p-value; Significant indicates whether the difference is statistically significant. We define the difference as (FRâEN)(FR-EN), such that positive values indicate higher performance in French. Appendix N Effect of Translated Benchmarks on Performance and Confidence Figure 5: Relationship between accuracy gain (ÎâEâM EM) and change in confidence on incorrect predictions (Îâpmax,wrong p_ ,wrong) between the translated and native benchmarks. Positive values of Îâpmax,wrong p_ ,wrong indicate increased confidence on incorrect predictions. Appendix O Computational Resources and Environmental Impact Table 14 summarizes the computational resources and environmental impact associated with each adaptation strategy, aggregated by model size. For clarity and conciseness, we do not report the consumption of each individual training run. Instead, we provide a representative summary per model size and per adaptation strategy. In total, 36 training runs were performed across all experiments. Model Size Strategy Dataset size (KB) Epochs Batch-size Type of GPU Memory per GPU (GB) Number of GPUs Training time (hours) Emissions (g CO2e) Cost (USD) CPT 4 000 000 3 4 NVIDIA A100 80 24 80 49 344 1 824.62 4B SFT 369 10 4 NVIDIA H100 80 3 146 11 256.6 832.48 CPT 4 000 000 3 2 NVIDIA A100 80 32 40 32 896 1 216.42 7B SFT 369 10 4 NVIDIA H100 80 1 190 4 883 361.12 CPT 4 000 000 3 2 NVIDIA H100 80 32 100 82 240 6 082.08 13B SFT 369 10 4 NVIDIA H100 80 6 122 18 812.4 1 391.27 Table 14: Summary of computational resources and environmental impact for different adaptation strategies, aggregated by model size. Reported values correspond to a representative training configuration per strategy. CPT+SFT costs are obtained by summing CPT and SFT. The CPT+SFT strategy is not reported as a separate entry in the table, as its computational cost and environmental impact correspond to the sum of the CPT and SFT phases. Reporting CPT and SFT independently therefore fully characterizes the overall resource usage of the combined strategy. We report, for each configuration, the dataset size, number of epochs, batch size, GPU type, GPU memory, number of GPUs, total training time, estimated carbon emissions (in gCO2e), and estimated monetary cost (in USD). Carbon emissions and cost estimates are derived from documented power consumption profiles and usage costs of the underlying high-performance computing infrastructure. All experiments were conducted on the Jean Zay supercomputer operated by GENCI-IDRIS777http://w.idris.fr/docs/jean-zay/jean-zay/jean-zay-presentation/. O.1 Analysis Overall, the results highlight a clear contrast between CPT and SFT in terms of computational cost and environmental impact. CPT is consistently the most resource-intensive strategy, driven by large-scale datasets, longer effective compute time, and high degrees of GPU parallelism. In contrast, SFT incurs substantially lower emissions and monetary costs across all model sizes. This difference is not only due to the smaller dataset size, but also to the use of parameter-efficient fine-tuning: SFT is implemented with DoRA adapters rather than full weight updates, significantly reducing both memory usage and energy consumption. Despite longer wall-clock durations in some configurations, the overall compute footprint of SFT remains markedly lower than that of CPT. As model size increases, CPT costs grow rapidly, particularly for the 13B setting, where energy consumption and carbon emissions increase sharply. SFT, while also scaling with model size, remains comparatively efficient due to its parameter-efficient design. These findings underscore the importance of adaptation strategies that balance performance gains with computational and environmental sustainability. Appendix P Pretraining Data Contamination Study: Was NACHOS Seen During Pretraining? Because most of the base models we evaluate (Gemma, MedGemma, Mistral, and Llama) do not disclose their full pretraining mixtures, we conducted a small contamination study to probe whether the French biomedical NACHOS corpus may have been included (or partially included) in their pretraining data. This appendix reports two complementary, lightweight detection protocols inspired by the broader literature on memorization and pretraining-data detection in large language models (Ravaut et al., 2024) P.1 Protocol 1: PrefixâContinuation Reproduction + Likelihood Heuristics Idea. If a model has memorized (or near-memorized) training documents, conditioning on a prefix may lead it to reproduce the exact continuation, or to assign a noticeably higher likelihood to the true continuation than to a perturbed version. This is conceptually related to training-data extraction / memorization diagnostics used in prior work (Carlini et al., 2021). Implementation. Using a sample of n=1915n=1915 NACHOS documents, we split each document into a prefix (first 400 characters) and a continuation (rest). For each sampled document, we: (i) generate up to 200 new tokens from the prefix (greedy decoding), and compute ROUGE-L between the generated continuation and the gold continuation; (i) compute the length of the longest common prefix (LCP) between generated and gold continuations; (i) compute the perplexity of the gold continuation conditioned on the prefix, and compare it to the perplexity of a lightly perturbed continuation (character swaps + whitespace noise), reporting the ratio PPLâ(gold)/PPLâ(perturbed)PPL(gold)/PPL(perturbed). We flag a case as âsuspiciousâ if any of the following holds: ROUGE-L â„0.7â„ 0.7, LCP â„200â„ 200 characters, or PPLâ(gold)/PPLâ(perturbed)â€0.85PPL(gold)/PPL(perturbed)†0.85. Results. Across models, ROUGE-L remained very low and we observed no exact continuation matches, which does not support verbatim memorization of long continuations under this setup. However, the fraction of items flagged as âsuspiciousâ is extremely high (0.82â0.96), which indicates that our heuristic is likely over-sensitive (in particular, the perturbation and/or the chosen ratio threshold may dominate the flagging decision). âą Llama-2-7B: ROUGE-L =0.031=0.031, exact matches =0/1915=0/1915, suspicious fraction =0.959=0.959. âą Llama-2-13B: ROUGE-L =0.020=0.020, exact matches =0/1915=0/1915, suspicious fraction =0.964=0.964. âą Mistral-7B: ROUGE-L =0.014=0.014, exact matches =0/1915=0/1915, suspicious fraction =0.944=0.944. âą MedGemma-4B: ROUGE-L =0.018=0.018, exact matches =0/1915=0/1915, suspicious fraction =0.821=0.821. âą Gemma-3-4B: ROUGE-L =0.019=0.019, exact matches =0/1915=0/1915, suspicious fraction =0.835=0.835. Interpretation. Given the near-zero reproduction scores (ROUGE-L, exact match) but massive âsuspiciousâ rates, this first protocol is inconclusive as a contamination detector in our setting: it does not show direct copying, and the likelihood-based heuristic is too unstable without a careful calibration procedure and stronger perturbations/controls. This is consistent with known difficulties of turning likelihood signals into reliable membership decisions without explicit calibration (Yeom et al., 2018). P.2 Protocol 2: DC-PDD (Divergence-based Calibration Pretraining Data Detection) Idea. We also tested a dedicated pretraining-data detection score, DC-PDD, which estimates a per-text statistic ÎČâ(x)ÎČ(x) combining (i) the model probability of next tokens and (i) reference token frequencies estimated from a large background corpus DâČD (here, French OSCAR888https://oscar-project.org/). The method is designed to be more robust than raw perplexity by incorporating a calibration term from DâČD (Zhang et al., 2024). Implementation. For each model, we first build a tokenizer-specific unigram table pâ(v;DâČ)p(v;D ) from OSCAR-FR (streaming counts, capped number of documents), then compute DC-PDD ÎČâ(x)ÎČ(x) on: (i) 1,000 NACHOS samples, and (i) a synthetic control set (ânon-memberâ) of biomedical texts generated to be unlikely to appear in any public pretraining mixture. We report distributional statistics (median, p75/p90/p95, mean, std) for both sets and a separation diagnostic Îmedian=medianâ(ÎČnachos)âmedianâ(ÎČcontrol) _median=median( _nachos)-median( _control). Why synthetic controls? (Major limitation) Gemma-family models were released recently (June 2025), and we could not reliably curate a sufficiently large set of web-native biomedical French texts written after the model release date to serve as a credible âdefinitely-non-memberâ control. As a consequence, we used synthetic biomedical controls, which weakens the study: synthetic controls differ from natural corpora in style and token statistics, and thus may artificially inflate separation (or mask it), independently of membership. We therefore treat DC-PDD results as indicative only, not as evidence of true pretraining inclusion. Results. DC-PDD yields consistently lower scores on NACHOS than on the synthetic controls (negative Î ), suggesting the models assign slightly more âin-distributionâ likelihood structure to NACHOS than to the synthetic texts. The separation is small for Mistral/Llama and somewhat larger for Gemma/MedGemma: âą Mistral-7B: Îmedianââ3.23Ă10â4 _medianâ-3.23Ă 10^-4. âą Llama-2-7B: Îmedianââ3.58Ă10â4 _medianâ-3.58Ă 10^-4. âą Llama-2-13B: Îmedianââ2.94Ă10â4 _medianâ-2.94Ă 10^-4. âą Gemma-3-4B: Îmedianââ8.20Ă10â4 _medianâ-8.20Ă 10^-4. âą MedGemma-4B: Îmedianââ6.77Ă10â4 _medianâ-6.77Ă 10^-4. Interpretation. While DC-PDD produces a consistent ordering (Nachos << Control), this cannot be confidently attributed to pretraining membership because our control set is synthetic and therefore not distribution-matched. In other words, the observed separation may reflect domain/style differences rather than exposure during pretraining. As prior work emphasizes, robust pretraining-data detection typically requires carefully constructed controls and/or calibrated baselines (e.g., Min-K% variants, calibrated likelihood tests), which we could not fully satisfy here (Zhang et al., 2024). P.3 Summary and Takeaways Overall, these experiments do not provide strong evidence for (or against) NACHOS being included in the undisclosed pretraining mixtures: (i) we do not observe continuation copying under our greedy prefixâcontinuation setup; (i) DC-PDD shows a small but consistent separation between NACHOS and synthetic controls, but the lack of a reliable post-release, naturally occurring biomedical control corpus makes the conclusion weak. We therefore report these results for transparency, but we do not use them to support any causal claim about pretraining contamination in the main analysis.