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When Reranking Hurts: Uncertainty-Based Gating for Few-Shot Reranking
Orian Dabod, Amir DN Cohen, Gabriel Stanovsky
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Status: succeeded | Model: Gemma-4-26B-A4B | Prompt: intel-v1 | Confidence: 96%
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Summary
The paper introduces 'Training-Free Gated Reranking', a method to optimize few-shot selection in Large Language Models (LLMs). It challenges the assumption that reranking retrieved examples always improves performance, demonstrating that reranking can actually degrade performance on 'easy' instances. The proposed method uses the model's initial generation perplexity as an uncertainty signal to decide whether to trigger a reranking step. Experiments across 8 LLMs (3B to 70B parameters) on Machine Translation (MT) and Natural Language Understanding (NLU) tasks show that this approach reduces computational costs by 15%-80% while improving average performance by up to 2%, effectively balancing resource efficiency and model quality.
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Perplexity â measures â Uncertainty
confidence 100% · This score is derived from the inverse perplexity of the generation: U(M,x,C) = 1 - PPL_M(y_hat | x, c1...ck)^-1
Training-Free Gated Reranking â uses â Perplexity
confidence 100% · uses the perplexity of the LLM's initial generation to rerank examples only when the model is uncertain.
Training-Free Gated Reranking â improves â Machine Translation
confidence 90% · demonstrate that our approach reduces computational costs by 15%-80% while improving average performance by up to 2%
Training-Free Gated Reranking â improves â Natural Language Understanding
confidence 90% · demonstrate that our approach reduces computational costs by 15%-80% while improving average performance by up to 2%
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Abstract
Abstract:Few-shot selection typically assumes that reranking retrieved examples always improves performance. We challenge this view by identifying that the expensive reranking step can in fact degrade performance. Instead, we propose \emph{Training-Free Gated Reranking}, which decides whether to rerank the few-shot examples based on the model's uncertainty. Extensive experiments across 8 LLMs, covering 7 NLU datasets and 9 MT domain-language combinations, demonstrate that our approach reduces computational costs by 15\%-80\% while improving average performance by up to 2\%. These findings indicate that higher computational cost does not guarantee better performance, and that reranking is most beneficial when targeted at high-uncertainty instances.
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- Source: https://arxiv.org/abs/2606.31087v2
- Canonical: https://arxiv.org/abs/2606.31087v2
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When Reranking Hurts: Uncertainty-Based Gating for Few-Shot Reranking Orian Dabod 1 , Amir DN Cohen 2 , Gabriel Stanovsky 1 1 The Hebrew University of Jerusalem, 2 OriginAI / Ramat Gan, Israel orian.dabod@mail.huji.ac.il Abstract Few-shot selection typically assumes that reranking retrieved examples always improves performance. We challenge this view by iden- tifying that the expensive reranking step can in fact degrade performance. Instead, we pro- pose Training-Free Gated Reranking, which decides whether to rerank the few-shot exam- ples based on the modelâs uncertainty. Exten- sive experiments across 8 LLMs, covering 7 NLU datasets and 9 MT domain-language com- binations, demonstrate that our approach re- duces computational costs by 15%-80% while improving average performance by up to 2%. These findings indicate that higher computa- tional cost does not guarantee better perfor- mance, and that reranking is most beneficial when targeted at high-uncertainty instances. 1 Introduction Recent work has found that adaptive few-shot se- lection can improve the performance of LLMs on in-context learning tasks (Agrawal et al., 2023; Chi- tale et al., 2024; Liu et al., 2022). In particular, several works adopt a âretrieve-then-rerankâ ap- proach, fetching a broad pool of candidates and using trained cross-encoders (Li et al., 2023; Wang et al., 2024b; Rubin et al., 2022) or training-free scorers to select demonstrations for a specific in- ference sample (Wu et al., 2023; Peng et al., 2024). However, reranking with repeated LLM calls in- creases computational costs, total token consump- tion can increase by 13.4Ăfor MT and by 29.5Ă for NLU. 1 To address these concerns, we propose Training- Free Gated Reranking, a simple yet effective ap- proach, which uses the perplexity of the LLMâs initial generation to rerank examples only when the 1 Calculated per task, as the total sum of tokens across all models and datasets. Llama 3BQwen 3BLlama 8B Command R7BAya 8BMistral 8B Qwen 32BLlama 70B 020406080100 â6% â4% â2% 0% 2% Relative BLEU Change (%) (a) Machine Translation (MT) Tasks 020406080100 â2% 0% 2% Token Saving (%) Relative Performance Change (%) (b) Natural Language Understanding (NLU) Figure 1: Relative performance impact versus computational token savings achieved via selective reranking for Machine Translation (MT, measured in BLEU) and Natural Language Understanding (NLU) tasks. The majority of models (3Bâ 70B) exhibit performance gains, though the optimal savings window shifts from 15â50% for MT to roughly 50â80% for most NLU models. model is uncertain. Rather than reranking every instance, we apply the reranking step exclusively when the inputâs perplexity falls above a predefined threshold. Our approach improves efficiency while match- ing or slightly surpassing performance across vari- ous models and datasets. Figure 1 shows that tun- arXiv:2606.31087v2 [cs.CL] 1 Jul 2026 ing the perplexity threshold for reranking yields computational savings of 15%-80% while main- taining or surpassing baseline performance. Our manual analysis confirms that reranking provides clear gains for difficult instances, but can degrade performance when applied to easy instances. Over- all, our approach presents a convenient tradeoff between resources and performance across 8 mod- els ranging from 3B to 70B parameters, covering 9 combinations of language pairs and specialized domains, as well as 7 NLU datasets. 2 2 Perplexity-Based Reranking of Few-Shot Examples We propose a simple approach that adaptively allo- cates computational resources to choose few-shot examples based on the modelâs intrinsic uncer- tainty. Formal definitions.Given an LLMM, an input xand a large pool of candidate demonstrations C = ((x 1 ,y 1 ),..., (x n ,y n )), each consisting of an input and a corresponding gold label, ranked according to their relevance tox, we are looking for a function: T(M,x,C)7âc 1 ,...,c k |c i âC(1) That is, a selection ofkdemonstration samples from the pool according to x. Method. We start by generating a prediction without rerankingËy = M(x,c 1 ,...,c k ), and use it to compute a normalized uncertainty scoreU â [0, 1] . This score is derived from the inverse per- plexity of the generation: U(M,x,C) = 1â PPL M (Ëy | x,c 1 ,...,c k ) â1 (2) Where, and PPL computes the conditional per- plexity ofËyonxand the firstkexamples.Uis in the range[0, 1], where larger values indicate that the model is less certain in its own prediction. We then define our demonstration selection func- tionTbased on a predefined uncertainty threshold Ï : 2 Code and experimental data are provided in the supple- mentary material for review, and will be made publicly avail- able upon acceptance. T(M,x,C) = ( ((x 1 ,y 1 ),... (x k ,y k )) U †Ï, rerank(M,x,C)U > Ï (3) wherererankis defined as the conditional en- tropy rerank (Peng et al., 2024): rerank(M,x,C) = Top-k (x i ,y i )âC âPPL M (x| (x i ,y i )) (4) In practice, we calibrate the thresholdÏto max- imize performance on a development set. During this calibration phase, we apply a moving average with a window size of 5 to smooth local variance. 3 Evaluation 3.1 Experimental Setup We list below key experimental details, see more details in the Appendix. Tasks and models. We evaluate our approach across 8 LLMs spanning 3Bâ70B parameters, com- pared to a full reranking baseline (Peng et al., 2024), assessing performance on both natural lan- guage understanding (NLU) and machine trans- lation (MT) tasks. Specifically, we adopt the NLU benchmarks used by Peng et al. (2024): SST-2, SST-5 (Socher et al., 2013), CR, AgNews, Subj (Wang et al., 2019), MNLI (Williams et al., 2018), and QNLI (Wang et al., 2019). For MT, we use three domain specific corpora (Koehn and Knowles, 2017): EMEA (medical) (Tiedemann, 2012), JRC-Acquis (legal) (Steinberger et al., 2006), and KDE (technical) (Tiedemann, 2012). We consider both translation directions between En- glish and Spanish, Portuguese, and German, yield- ing six directions per domain. We sample 1,000 parallel sentence pairs for each domain-direction combination, partitioned into 200 development ex- amples for threshold tuning and 800 test examples for evaluation. All results are averaged over 20 random splits for statistical robustness. Baselines. Baselines include retrieval-basedk- shot selection with BM25 (Robertson and Zaragoza, 2009) and dense retrieval using e5-base- v2 or multilingual-e5-base depending on the lan- guage (Wang et al., 2022, 2024a), and always- rerank (Ï = 0, reranking for every input at O(N)). We also compare gating signals to simple input proxies (e.g., source length, source entropy) Global (All)Small ModelsBigger Models MethodPerf. âSave. %Perf. âSave. %Perf. âSave. % Machine Translation (BLEU / COMET) No Reranking37.09/81.05100.033.37/79.46100.038.33/81.57100.0 Full Reranking38.32/81.370.034.77/79.890.039.51/81.860.0 Gating (dev-set calibrated)38.42 â /81.39 20.8634.95 â /79.94 20.5239.58 â /81.88 20.98 Gating (test-set calibrated)38.69 â /81.4317.4235.19 â /79.9819.2239.85 â /81.9216.82 Natural Language Understanding (Accuracy) No Reranking79.88100.077.16100.080.78100.0 Full Reranking80.730.078.450.081.500.0 Gating (dev-set calibrated)80.8154.378.6050.281.5555.6 Gating (test-set calibrated)81.41 â 47.1679.30 â 46.6982.11 â 47.32 Table 1: Performance summary across tasks and model sizes. Performance (Perf.) shows BLEU/COMET for MT and Accuracy for NLU. Bold indicates row maxima;underlinedvalues exceed Full Reranking performance. Gating (dev-set calibrated) uses dev-setÏ, while Gating (test-set calibrated) uses test-setÏ. â denotes a statistically significant improvement over No Reranking (p < 0.05). Exact p-values are provided for transparency. and an uncertainty proxy (token-level logit gap - TARG) (Wang et al., 2025). Hyperparameters and metrics. We fixk = 5 demonstrations and a candidate pool ofN = 100, report MT quality with BLEU (Papineni et al., 2002) and COMET (wmt22-comet-da) (Rei et al., 2022), and NLU quality with accuracy. Follow- ing scaling laws for inference compute (Kaplan et al., 2020) and standard open-weight serving met- rics (Griggs et al., 2024), we evaluate efficiency us- ing the unweighted sum of input and output tokens across all processing stages: (a) initial draft genera- tion, (b) second-pass generation after reranking for triggered cases, and (c) all conditional perplexity computations over theN = 100candidates. We report relative savings against an always-reranking baseline. 3.2 Results Our experiments yield several interesting observa- tions. Always reranking is not the optimal policy for few-shot selection in MT and NLU. Apply- ing reranking to every query is highly inefficient and unnecessary for maintaining quality. Table 1 demonstrates that our practical Empirical Gating method reduces average computational costs by 20.86% and 54.3% for MT and NLU, while achiev- ing performance on par with Full Reranking (38.42 vs 38.32 avg BLEU; 80.81 vs 80.73 avg Accuracy). Furthermore, using a post-hoc test-set calibrated gating threshold achieves comparable cost reduc- tions (17.42% / 47.16%) while slightly increas- ing Full Reranking performance (+0.37 avg BLEU, +0.68 avg Accuracy), demonstrating there is room for improvement. Selective reranking via uncertainty can im- prove performance, especially for smaller mod- els. Selective reranking remains highly competi- tive with the Full Reranking baseline across model scales. Table 1 highlights that this dynamic is most pronounced for small models, Full Reranking per- formance (34.77 avg BLEU / 78.45 avg Accuracy) is slightly improved upon by our retrospective Gat- ing (test-set calibrated) (+0.42 avg BLEU / +0.85 avg Accuracy) and practical Gating (dev-set cali- brated) results (+0.18 avg BLEU / +0.15 avg Ac- curacy) while yielding average token savings of 19.22% / 46.69% and 20.52% / 50.2%. Larger models in the optimal Gating (test-set calibrated) settings show smaller yet positive margins (+0.34 avg BLEU / +0.61 avg Accuracy), while the Gating (dev-set calibrated) yields strong savings (20.98% and 55.6%) and comparable performance (+0.07 avg BLEU / +0.05 avg Accuracy) demonstrating that selective application remains a highly efficient alternative even at scale. Selective reranking via uncertainty provides ef- ficient way to optimize performance with mini- mal impact on task performance. As Figure 1 illustrates, adjusting the gating threshold provides a way to balance cost and quality. This tradeoff relies on the correlation between the LLMâs initial uncertainty and the utility of the reranker. This al- StrategyTaskScoreSavings No RerankingMT37.09100.0% NLU79.88100.0% Full RerankingMT38.320.0% NLU80.730.0% TARGMT38.158.6% NLU80.4635.6% Source EntropyMT38.1911.8% NLU80.4642.2% Word LengthMT38.1117.1% NLU80.3738.1% Uncertainty (Ours)MT38.4220.9% NLU80.8154.3% Table 2: Comparison of gating indicators averaged across all models for MT and NLU. Thresholds (Ï) for each strategy are calibrated on a development set and evaluated on a test set. Uncertainty achieves the best performance-efficiency balance. Error CauseMTNLUOverall Reranking errors Structural Template212344 High Variance4711 Other505 No Reranking errors Domain/Term Shift15823 High Variance9918 Relational Mapping099 Bleu Misleading404 Other246 Table 3: Distribution of error causes when reranking degrades performance compared to baseline vs. when reranking im- proved performance on translation and NLU tasks. lows us us to to reduce average token consumption from 15% to 80%. Uncertainty gating outperforms other gat- ing methods. Alternative gating signals fail to achieve the same balance of quality and efficiency. As shown in Table 2, where we compare our ap- proach against several alternative baseline metrics used for the same gating purpose: the perplexity of the input text (Source Entropy), the count of words (Word Length), along with TARG (Wang et al., 2025). 4 Manual Qualitative Analysis To understand the mechanics driving the perfor- mance trade-offs of uncertainty-based gating, we manually annotate and analyze instances with the highest and lowest uncertainty scores. Specifically, we examine some of the top 30 instances (highest uncertainty, reranking beneficial) and bottom 30 instances (lowest uncertainty, reranking degraded) across both Machine Translation (MT) and Natural Language Understanding (NLU) tasks to diagnose how the few-shot examples influence the modelâs generation. See Table 3 and Appendix Table 7. High uncertainty reveals weak baseline retrieval. Under high uncertainty, the baseline frequently re- trieves misleading demonstrations, such as out-of- domain examples in MT (15 instances) or missed Relational Mappings in NLU (9 instances). The reranker resolves these issues by correctly identi- fying the taskâs structural logic and domain con- straints. By successfully retrieving examples that enforce low variance, specialized terminology or exact relationships (e.g., mapping a neighborhood to a borough), reranking effectively grounds the model and reduces hallucinations. Low uncertainty indicates strong baseline re- trieval. For low-uncertainty instances, the base- line already retrieves highly relevant, format- preserving contexts. Here, reranking can actu- ally degrade performance. The primary cause across both MT (21 instances) and NLU (23 in- stances) is the disruption of Structural Templates. While the baseline retrieves near-exact syntactic templates, the reranker often overrides them with examples that are topically relevant but structurally varied. Furthermore, reranking can introduce high- variance examples with divergent meanings or lexi- cal distractions that confuse the model. (Note: A small subset of MT errors were "BLEU Mislead- ing," where the rerankerâs valid translation was unfairly penalized by the metric 5 Conclusion We show that reranking few-shot examples is not always beneficial and can even hurt performance. Instead, we introduce Training-Free Gated Rerank- ing, which selectively ranks when the model is un- certain, reducing computation by 15%â80% while improving average performance by up to 2%. Over- all, our findings suggest that targeted reranking can break the usual tradeoff between higher computa- tional cost and better downstream quality. 6 Limitations Our approach presents three primary limitations. First, the gating mechanism relies on an empiri- cally calibrated threshold from a development set; distribution shifts between development and test data can cause suboptimal thresholding. Second, calculating the uncertainty score requires generat- ing an initial, non-reranked prediction. For tasks with long output sequences, the latency of this ini- tial step may reduce the efficiency gained from skipping the reranking phase. Finally, the method requires access to token-level perplexity, limiting its use to models and APIs that expose logits. References Sweta Agrawal, Chunting Zhou, Mike Lewis, Luke Zettlemoyer, and Marjan Ghazvininejad. 2023. In- context examples selection for machine translation. In Findings of the Association for Computational Linguistics: ACL 2023, pages 8857â8873, Toronto, Canada. Association for Computational Linguistics. Pranjal A. Chitale, Jay Gala, and Raj Dabre. 2024. An empirical study of in-context learning in llms for machine translation. Tyler Griggs, Xiaoxuan Liu, Jiaxiang Yu, Doyoung Kim, Wei-Lin Chiang, Alvin Cheung, and Ion Stoica. 2024. MĂ©lange: Cost efficient large language model serving by exploiting gpu heterogeneity. Jared Kaplan, Sam McCandlish, Tom Henighan, Tom B. Brown, Benjamin Chess, Rewon Child, Scott Gray, Alec Radford, Jeffrey Wu, and Dario Amodei. 2020. Scaling laws for neural language models. Philipp Koehn and Rebecca Knowles. 2017. Six chal- lenges for neural machine translation. In Proceedings of the First Workshop on Neural Machine Translation, pages 28â39, Vancouver. Association for Computa- tional Linguistics. Xiaonan Li, Kai Lv, Hang Yan, Tianyang Lin, Wei Zhu, Yuan Ni, Guotong Xie, Xiaoling Wang, and Xipeng Qiu. 2023. Unified demonstration retriever for in- context learning. In Proceedings of the 61st Annual Meeting of the Association for Computational Lin- guistics (Volume 1: Long Papers), pages 4644â4668, Toronto, Canada. Association for Computational Lin- guistics. Jiachang Liu, Dinghan Shen, Yizhe Zhang, Bill Dolan, Lawrence Carin, and Weizhu Chen. 2022. What makes good in-context examples for GPT-3?In Proceedings of Deep Learning Inside Out (DeeLIO 2022): The 3rd Workshop on Knowledge Extrac- tion and Integration for Deep Learning Architectures, pages 100â114, Dublin, Ireland and Online. Associa- tion for Computational Linguistics. Kishore Papineni, Salim Roukos, Todd Ward, and Wei- Jing Zhu. 2002. Bleu: a method for automatic evalu- ation of machine translation. In Proceedings of the 40th Annual Meeting of the Association for Compu- tational Linguistics, pages 311â318, Philadelphia, Pennsylvania, USA. Association for Computational Linguistics. Keqin Peng, Liang Ding, Yancheng Yuan, Xuebo Liu, Min Zhang, Yuanxin Ouyang, and Dacheng Tao. 2024. Revisiting demonstration selection strategies in in-context learning. Ricardo Rei, Marcos Treviso, Nuno M. Guerreiro, Chrysoula Zerva, Ana C Farinha, Christine Maroti, JosĂ© G. C. de Souza, Taisiya Glushkova, Duarte Alves, Luisa Coheur, Alon Lavie, and AndrĂ© F. T. Martins. 2022. CometKiwi: IST-unbabel 2022 sub- mission for the quality estimation shared task. In Proceedings of the Seventh Conference on Machine Translation (WMT), pages 634â645, Abu Dhabi, United Arab Emirates (Hybrid). Association for Com- putational Linguistics. Stephen E. Robertson and Hugo Zaragoza. 2009. The probabilistic relevance framework: Bm25 and be- yond. Found. Trends Inf. Retr., 3:333â389. Ohad Rubin, Jonathan Herzig, and Jonathan Berant. 2022. Learning to retrieve prompts for in-context learning. In Proceedings of the 2022 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Tech- nologies, pages 2655â2671, Seattle, United States. Association for Computational Linguistics. Richard Socher, Alex Perelygin, Jean Wu, Jason Chuang, Christopher D. Manning, Andrew Ng, and Christopher Potts. 2013. Recursive deep models for semantic compositionality over a sentiment treebank. In Proceedings of the 2013 Conference on Empiri- cal Methods in Natural Language Processing, pages 1631â1642, Seattle, Washington, USA. Association for Computational Linguistics. Ralf Steinberger, Bruno Pouliquen, Anna Widiger, Camelia Ignat, TomaĆŸ Erjavec, Dan Tufi ̧s, and DĂĄniel Varga. 2006.The JRC-Acquis: A multilingual aligned parallel corpus with 20+ languages.In Proceedings of the Fifth International Conference on Language Resources and Evaluation (LRECâ06), Genoa, Italy. European Language Resources Associ- ation (ELRA). Jörg Tiedemann. 2012. Parallel data, tools and inter- faces in OPUS. In Proceedings of the Eighth In- ternational Conference on Language Resources and Evaluation (LRECâ12), pages 2214â2218, Istanbul, Turkey. European Language Resources Association (ELRA). Alex Wang, Amanpreet Singh, Julian Michael, Felix Hill, Omer Levy, and Samuel R. Bowman. 2019. GLUE: A multi-task benchmark and analysis plat- form for natural language understanding. In 7th In- ternational Conference on Learning Representations, ICLR 2019, New Orleans, LA, USA, May 6-9, 2019. OpenReview.net. Liang Wang, Nan Yang, Xiaolong Huang, Binxing Jiao, Linjun Yang, Daxin Jiang, Rangan Majumder, and Furu Wei. 2022. Text embeddings by weakly- supervised contrastive pre-training. ArXiv preprint, abs/2212.03533. Liang Wang, Nan Yang, Xiaolong Huang, Linjun Yang, Rangan Majumder, and Furu Wei. 2024a. Multilin- gual e5 text embeddings: A technical report. Liang Wang, Nan Yang, and Furu Wei. 2024b. Learn- ing to retrieve in-context examples for large language models. In Proceedings of the 18th Conference of the European Chapter of the Association for Compu- tational Linguistics (Volume 1: Long Papers), pages 1752â1767, St. Julianâs, Malta. Association for Com- putational Linguistics. Yufeng Wang, Lu wei, and Haibin Ling. 2025. Targ: Training-free adaptive retrieval gating for efficient rag. Adina Williams, Nikita Nangia, and Samuel Bowman. 2018. A broad-coverage challenge corpus for sen- tence understanding through inference. In Proceed- ings of the 2018 Conference of the North American Chapter of the Association for Computational Lin- guistics: Human Language Technologies, Volume 1 (Long Papers), pages 1112â1122, New Orleans, Louisiana. Association for Computational Linguis- tics. Zhiyong Wu, Yaoxiang Wang, Jiacheng Ye, and Ling- peng Kong. 2023. Self-adaptive in-context learn- ing: An information compression perspective for in- context example selection and ordering. In Proceed- ings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 1423â1436, Toronto, Canada. Association for Computational Linguistics. Yue Yu, Wei Ping, Zihan Liu, Boxin Wang, Jiaxuan You, Chao Zhang, Mohammad Shoeybi, and Bryan Catanzaro. 2024. Rankrag: Unifying context rank- ing with retrieval-augmented generation in llms. In Advances in Neural Information Processing Systems 38: Annual Conference on Neural Information Pro- cessing Systems 2024, NeurIPS 2024, Vancouver, BC, Canada, December 10 - 15, 2024. 7 Appendix 7.1 Prompt Template We utilized the following chat template for all Training-Free Gated Reranking experiments. Dy- namic fields are denoted in brackets. MT Prompt Template [System Message] You are an expert translator. Task: Translate [Source Language] to [Target Language]. Rule 1: Output ONLY the translated text. Rule 2: Do not engage in conversation or explain the translation. Rule 3: CRITICAL: You have been pro- vided with a "Reference Translation" in the context. You MUST copy the terminology and structure from the Reference Transla- tion exactly. Do not rephrase. [User Message] ### Reference Examples: Input ([Source Language]):[Retrieved Source Text 1] Output ([Target Language]): [Retrieved Tar- get Text 1] Input ([Source Language]):[Retrieved Source Text 2] Output ([Target Language]): [Retrieved Tar- get Text 2] ... ### Current Task: Input ([Source Language]): [Input Source Text] Output ([Target Language]): NLU Prompt Template [System Message] You are an AI assistant. Complete the given task by outputting ONLY the required label. Do not explain. [User Message] ### Reference Examples: [Retrieved Source Text 1] [Retrieved Target Label 1] [Retrieved Source Text 2] [Retrieved Target Label 2] ... ### Current Task: [Input Source Text] 7.2 Hyperparameter Selection To select our architectural choices, we conducted a three-stage ablation study on the KDE dataset using the Llama 3B model. Retrieval Mechanism and Shot Count. First, we determined the optimal retrieval backbone. As shown in Table 4, Dense-based retrieval com- bined with reranking consistently outperforms lex- ical (BM25) and random selection. Crucially, the performance gap widens as the number of shots (k) increases, peaking atk = 5. This validates our decision to fixk = 5for the main experiments, as it maximizes the context windowâs utility. StrategykCOMETBLEUChrF Zero-Shot069.817.1744.14 Random171.2718.7446.05 371.2619.1646.07 570.9419.1045.82 Dense173.5623.2850.78 373.9824.3551.80 573.7924.7452.19 BM25173.0923.8650.65 374.0325.1352.15 574.2924.9752.33 BM25 Full Reranking173.8524.4051.38 374.2026.0552.54 574.5126.2152.81 Dense Full Reranking173.7624.1551.45 374.6526.3053.19 574.8026.7953.44 Table 4: Impact of Retrieval Strategy and Shot Count (k). Ablation study on the KDE (EnâDe) dataset. While static retrieval methods (Random, BM25, E5) show diminish- ing returns or saturation at higherk, the reranking strategies continue to improve, with E5 + TopP+ConE atk = 5estab- lishing the upper bound for performance. Bold values indicate the optimal shot count for each specific strategy. Comparison of Reranking Algorithms. To de- termine the optimal training-free method, we evaluated the effectiveness of Conditional En- tropy Rerank function against alternative strate- gies, including Source Entropy Reranking, TARG Reranking which is based on Wang et al. (2025), RankRAG Reranking which follows Yu et al. (2024) without training. As shown in Table 5, while some reranking methods offer some gains, utilizing the Conditional Entropy Rerank yields the most robust performance. StrategyCOMETBLEUChrF Source Entropy Reranking69.8017.1744.14 RankRAG Reranking71.5118.9246.71 TARG Reranking74.5126.3452.88 Conditional Entropy Rerank74.8026.7953.44 Table 5: Re-Ranking Strategies.Evaluation on KDE (EnâDe) usingLlama-3.2-3B-Instruct(Llama 3B) (k = 5). Sensitivity to Candidate Pool Size. Finally, we analyzed the computational trade-off regarding the cardinality of the candidate pool|C| = N. As detailed in Table 6, increasing the search space from5Ă kto20Ă kyields steady improvements. However, performance plateaus beyondN = 100 (20Ă k). Consequently, we selected a pool size of 100 for all experiments to balance maximum utility with inference latency. Dense Full Reranking NCOMETBLEUChrF 174.0424.9552.42 574.4326.0152.80 1074.4226.2053.08 2074.8826.8053.47 3074.8327.0853.38 Table 6: Candidate Pool Sensitivity. Increasing pool size (N) yields gains up toN = 100(MULT=20), after which performance saturates. 7.3 Detailed examples used in Analysis Table 7 shows full details for the examples shown in the analysis section. 7.4 Performance Across Tasks and Models Table 8 details the results across individual datasets, while Table 9 provides a model-by-model break- down. Tables 11 and 10 shows Gated (test-set cali- brated) and Gated (dev-set calibrated) results per model and per dataset. The data indicate that our gating strategy generally yields higher performance than full reranking while simultaneously maintain- ing consistent computational efficiency. Although empirical performance occasionally trails that of full reranking, the efficiency gains persist across all configurations. StrategyRetrieved In-Context Example (Shot)Final Model Output Case 1: Reranking Helped (Resolves Terminology Mismatch) Input (PT): As actualizaçÔes sobre o decurso do estudo e sobre o recrutamento serĂŁo apresentadas juntamente com os reavaliação anual/ RPS. Reference (EN): Progress and recruitment updates will be provided alongside the Annual Re-assessment/ PSURs. BaselineSrc: As actualizaçÔes do progresso e dos recrutamentos serĂŁo apresentadas juntamente com os PSURs normais. Tgt: Progress and recruitment updates will be provided alongside the standard PSURs. Updates on the study course and recruitment will be presented together with the annual review/RPS. RerankSrc: O sumĂĄrio da informação de segurança recolhida serĂĄ apresentado juntamente com os reavaliação anual/ RPSs. Tgt: Summary safety information gathered will be provided alongside the Annual Re-assessment/ PSURs. Updates regarding the course of the study and recruitment will be provided alongside the Annual Re-assessment/ PSURs. Case 2: Baseline Was Better (Reranking Caused Hallucination) Input (EN): Like all medicines, Xenical can cause side effects, although not everybody gets them. Reference (PT): Como todos os medicamentos, Xenical pode causar efeitos secundĂĄrios, no entanto estes nĂŁo se manifestam em todas as pessoas. BaselineSrc: Like all medicines, Arixtra can cause side effects, although not everybody gets them. Tgt: Como todos os medicamentos, Arixtra pode causar efeitos secundĂĄrios, no entanto, estes nĂŁo se manifestam em todas as pessoas. Como todos os medicamentos, Xenical pode causar efeitos secundĂĄrios, no entanto, estes nĂŁo se manifestam em todas as pessoas. Eng: Like all medicines, Xenical can cause side effects although not everybody gets them. RerankSrc: Take special care with XENICAL Weight loss may also affect the dose of medicines taken for other conditions... Tgt: Tome especial cuidado com XENICAL A perda de peso pode tambĂ©m obrigar a alterar a dose de medicamentos... Tome especial cuidado com XENICAL A perda de peso pode tambĂ©m obrigar a alterar a dose de medicamentos que esteja a tomar para outras doenças (p. ex. colesterol elevado ou diabetes). Eng: Take special care with XENICAL Weight loss may also affect the dose of medicines taken for other conditions (e.g. high cholesterol or diabetes). Case 3: Baseline Was Better (Reranking Caused Template Mismatch) Input (EN): Like all medicines, STOCRIN can cause side effects, although not everybody gets them. Reference (PT): Como todos os medicamentos, STOCRIN pode causar efeitos secundĂĄrios, no entanto estes nĂŁo se manifestam em todas as pessoas. BaselineSrc: Like all medicines, Cetrotide can cause side effects, although not everybody gets them. Tgt: Como os demais medicamentos, Cetrotide pode causar efeitos secundĂĄrios, no entanto estes nĂŁo se manifestam em todas as pessoas. Como os demais medicamentos, STOCRIN pode causar efeitos secundĂĄrios, no entanto estes nĂŁo se manifestam em todas as pessoas. Eng: Like the other medicines, STOCRIN can cause secondary effects, however these do not manifest in all people. RerankSrc: Always notify your doctor immediately if you have these symptoms or any side effects while taking STOCRIN. Tgt: Informe sempre o seu mĂ©dico imediatamente se sentir qualquer um destes sintomas ou quaisquer efeitos indesejĂĄveis... Como todos os medicamentos, STOCRIN pode causar efeitos colaterais, embora nem todo mundo os obtenha. Eng: Like all medicines, STOCRIN can cause collateral effects, although not everyone obtains them. Case 4: Baseline Was Better (Reranking Lost Structural Template) Input Task (NLU): Some rooms have balconies. Can we know Some rooms have balconies off of them that overlook the ocean.? Reference Label: Maybe. BaselineTask: There are sea views from some rooms and there is also a swimming pool. Can we know Half the rooms are oceanview.? Label: Maybe. Maybe. RerankTask: Rooms have private lanais, refrigerators, and coffeemakers. Can we know Rooms have refigerators.? Label: Yes. No. Case 5: Reranking Helped (Resolves Relational Mapping) Input Task (NLU): In what borough is there a neighborhood called Huguenot? Can we know A small group of Huguenots also settled on the south shore of Staten Island along the New York Harbor, for which the current neighborhood of Huguenot was named.? Reference Label: Yes. BaselineTask: The borough of Staten Island is primarily located on what island? Can we know This situation of boroughs separated by water led to the development of an extensive infrastructure of bridges and tunnels.? Label: No. No. RerankTask: In what borough is the Douglaston neighborhood located? Can we know In contrast, New York City also has neighborhoods that are less densely populated and feature free-standing dwellings.? Label: No. Yes. Table 7: Comparison of Baseline vs. Reranking In-Context Retrieval on Translation and NLU Quality DatasetBaselineFull RerankGated (Test-Set Calibrated)SavingsGated (Dev-Set Calibrated)Savings Machine Translation (BLEU) Medical_EMEA38.7739.8940.46 â 26%40.12 â 29% Medical_JRC-Acquis39.3940.8341.07 â 12%40.87 â 16% Medical_KDE33.1134.2634.53 â 15%34.27 â 18% Natural Language Understanding (Accuracy) AgNews91.6692.6392.67 â 47%92.34 â 58% CR93.7693.6294.61 â 88%93.7280% MNLI65.9067.5067.75 â 15%67.13 â 45% QNLI72.1073.5874.04 â 34%73.6347% SST-293.3794.0294.34 â 67%93.8959% SST-551.8151.3453.16 â 62%52.2560% Subj90.5692.4693.27 â 17%92.75 â 30% Table 8: Performance breakdown by dataset using Uncertainty. Gated (test-set calibrated) represents the theoretical upper bound, while Gated (dev-set calibrated) represents practical levels. Gated values exceeding Full Reranking are in bold.â denotes statistical significance against the baseline (p < 0.05). ModelBaselineFull RerankGated (Test-Set Calibrated)SavingsGated (Dev-Set Calibrated)Savings Machine Translation (BLEU) Llama-3.2-3B-Instruct34.2235.6936.00 â 19%35.73 â 20% Llama-3.3-70B-Instruct43.1644.1644.38 â 18%44.16 â 24% Meta-Llama-3.1-8B-Instruct37.2838.5739.03 â 22%38.73 â 26% Mistral-7B-Instruct-v0.335.0036.2336.53 â 11%36.31 â 15% Qwen2.5-32B-Instruct41.3842.5342.74 â 16%42.52 â 21% Qwen2.5-3B-Instruct32.5333.8634.38 â 19%34.16 â 21% aya-expanse-8b37.6438.5938.84 â 14%38.60 â 19% c4ai-command-r7b-12-202435.5236.9637.58 â 21%37.16 â 21% Natural Language Understanding (Accuracy) Llama-3.2-3B-Instruct76.3277.9978.47 â 36%77.70 â 46% Llama-3.3-70B-Instruct84.1285.0585.55 â 36%84.9348% Meta-Llama-3.1-8B-Instruct79.0679.7480.21 â 47%79.6055% Mistral-7B-Instruct-v0.378.3178.5579.76 â 62%79.3068% Qwen2.5-32B-Instruct85.9186.6787.13 â 49%86.59 â 54% Qwen2.5-3B-Instruct78.0178.9180.14 â 57%79.4955% aya-expanse-8b80.0680.7481.24 â 47%80.7849% c4ai-command-r7b-12-202477.2478.2278.76 â 43%78.1460% Table 9: Performance breakdown by model using Uncertainty. Gated (Test-Set Calibrated) represents the theoretical upper bound, while Gated (Dev-Set Calibrated) represents practical levels. Gated values exceeding Full Reranking are in bold.â denotes statistical significance against the baseline (p < 0.05). DatasetQwen 3BLlama 3BCommandMistralAyaLlama 8BQwen 32BLlama 70B EMEA (deâen) +0.44 BLEU (13.4%) +0.18 BLEU (19.9%) +0.76 BLEU (17.0%) +0.21 BLEU (17.3%) -0.06 BLEU (37.2%) +0.25 BLEU (32.4%) +0.12 BLEU (38.2%) -0.27 BLEU (27.7%) EMEA (enâde) +0.41 BLEU (26.5%) +0.41 BLEU (19.1%) -3.47 BLEU (18.2%) +0.26 BLEU (45.4%) +0.53 BLEU (31.1%) +0.70 BLEU (27.8%) -0.11 BLEU (34.5%) -0.34 BLEU (35.9%) EMEA (enâes) +0.38 BLEU (40.4%) +0.12 BLEU (37.1%) +0.23 BLEU (17.7%) +0.08 BLEU (15.5%) +0.42 BLEU (45.7%) +0.70 BLEU (55.8%) -0.12 BLEU (35.9%) -0.03 BLEU (26.6%) EMEA (esâen) +0.50 BLEU (29.5%) +0.36 BLEU (29.9%) +1.17 BLEU (38.5%) -0.20 BLEU (18.7%) +0.36 BLEU (12.1%) +0.28 BLEU (29.5%) +0.03 BLEU (32.1%) -0.27 BLEU (23.1%) EMEA (enâpt) +0.60 BLEU (24.2%) -0.03 BLEU (20.1%) +2.40 BLEU (30.9%) +1.77 BLEU (72.1%) +0.23 BLEU (52.7%) +1.28 BLEU (41.9%) +0.42 BLEU (24.8%) +1.18 BLEU (36.1%) EMEA (ptâen) -0.05 BLEU (4.1%) -0.20 BLEU (15.5%) +0.15 BLEU (20.0%) -0.06 BLEU (5.2%) -0.15 BLEU (13.6%) -0.13 BLEU (19.4%) +0.11 BLEU (24.4%) -0.17 BLEU (48.2%) JRC-Acquis (deâen) +0.50 BLEU (17.8%) -0.12 BLEU (29.1%) +0.41 BLEU (23.3%) +0.11 BLEU (29.0%) +0.01 BLEU (10.3%) -0.12 BLEU (28.0%) -0.15 BLEU (6.7%) -0.06 BLEU (15.3%) JRC-Acquis (enâde) +0.34 BLEU (20.2%) +0.05 BLEU (24.4%) +0.57 BLEU (32.2%) +0.05 BLEU (13.5%) -0.02 BLEU (20.7%) +0.32 BLEU (35.9%) +0.09 BLEU (19.5%) -0.10 BLEU (27.7%) JRC-Acquis (enâes) +0.82 BLEU (35.0%) +0.37 BLEU (26.4%) +0.09 BLEU (13.7%) +0.41 BLEU (20.9%) -0.05 BLEU (8.2%) -0.10 BLEU (22.0%) -0.03 BLEU (28.8%) +0.10 BLEU (33.9%) JRC-Acquis (esâen) +0.35 BLEU (8.1%) +0.03 BLEU (16.2%) +0.41 BLEU (28.7%) -0.09 BLEU (-2.7%) -0.10 BLEU (20.0%) +0.06 BLEU (28.5%) +0.04 BLEU (15.8%) +0.01 BLEU (18.8%) JRC-Acquis (enâpt) -0.04 BLEU (18.7%) -0.18 BLEU (4.4%) -0.07 BLEU (10.1%) -0.24 BLEU (-4.9%) -0.33 BLEU (8.5%) -0.22 BLEU (11.6%) -0.03 BLEU (7.6%) +0.03 BLEU (13.3%) JRC-Acquis (ptâen) -0.02 BLEU (-5.3%) -0.01 BLEU (-5.4%) -0.08 BLEU (2.2%) -0.22 BLEU (-1.8%) -0.05 BLEU (-2.6%) -0.41 BLEU (12.9%) -0.04 BLEU (8.1%) -0.20 BLEU (14.7%) KDE (deâen) +0.17 BLEU (18.5%) +0.11 BLEU (41.7%) +0.63 BLEU (29.7%) -0.12 BLEU (10.3%) -0.16 BLEU (13.6%) +0.56 BLEU (30.9%) +0.06 BLEU (14.5%) +0.07 BLEU (17.3%) KDE (enâde) +0.15 BLEU (14.2%) -0.09 BLEU (-0.9%) -0.01 BLEU (16.2%) -0.02 BLEU (6.2%) -0.14 BLEU (5.9%) -0.04 BLEU (6.6%) -0.09 BLEU (11.9%) -0.05 BLEU (13.6%) KDE (enâes) +0.28 BLEU (18.1%) +0.03 BLEU (12.3%) +0.01 BLEU (14.8%) -0.23 BLEU (6.8%) -0.24 BLEU (22.4%) -0.01 BLEU (14.1%) -0.16 BLEU (16.5%) -0.04 BLEU (12.4%) KDE (esâen) +0.40 BLEU (23.0%) -0.09 BLEU (19.2%) +0.19 BLEU (21.6%) -0.18 BLEU (7.7%) +0.06 BLEU (14.5%) -0.16 BLEU (28.5%) -0.33 BLEU (36.4%) +0.01 BLEU (18.1%) KDE (enâpt) +0.25 BLEU (25.3%) +0.16 BLEU (25.3%) +0.10 BLEU (3.1%) -0.09 BLEU (0.3%) -0.15 BLEU (1.1%) -0.02 BLEU (15.9%) -0.07 BLEU (11.9%) +0.00 BLEU (29.2%) KDE (ptâen) +0.02 BLEU (38.9%) -0.31 BLEU (33.6%) +0.08 BLEU (34.0%) -0.05 BLEU (4.0%) +0.08 BLEU (18.1%) -0.14 BLEU (32.8%) -0.01 BLEU (19.0%) -0.03 BLEU (23.8%) NLU_AgNews +0.01 Acc (72.9%) -0.39 Acc (66.2%) -0.14 Acc (48.7%) -0.00 Acc (80.7%) -0.11 Acc (43.7%) -0.26 Acc (58.6%) -0.36 Acc (55.7%) -0.30 Acc (40.5%) NLU_CR +0.11 Acc (66.2%) +1.20 Acc (71.9%) +0.43 Acc (91.2%) -0.32 Acc (78.0%) +0.13 Acc (89.6%) -0.61 Acc (79.0%) +0.21 Acc (83.1%) +0.05 Acc (84.0%) NLU_MNLI +0.29 Acc (35.0%) +0.10 Acc (44.3%) -0.61 Acc (54.4%) -0.23 Acc (42.3%) -0.50 Acc (46.0%) -0.23 Acc (62.0%) -0.19 Acc (32.3%) -1.06 Acc (42.5%) NLU_QNLI +0.93 Acc (35.3%) -0.80 Acc (18.8%) -0.91 Acc (67.6%) +1.35 Acc (74.3%) -0.05 Acc (27.5%) -0.28 Acc (30.4%) +0.01 Acc (67.7%) +0.84 Acc (51.0%) NLU_SST-2 -0.36 Acc (34.6%) -0.48 Acc (39.8%) +0.09 Acc (92.5%) +0.05 Acc (64.3%) -0.30 Acc (59.2%) -0.22 Acc (74.0%) +0.34 Acc (64.7%) -0.28 Acc (43.7%) NLU_SST-5 +1.95 Acc (70.4%) -0.71 Acc (52.2%) +0.87 Acc (57.9%) +0.65 Acc (59.0%) +1.68 Acc (57.3%) +1.51 Acc (70.4%) +0.47 Acc (61.1%) +0.87 Acc (55.0%) NLU_Subj +1.25 Acc (67.3%) -0.74 Acc (27.4%) -0.43 Acc (10.2%) +4.02 Acc (76.6%) -0.40 Acc (18.3%) -0.21 Acc (11.5%) -0.12 Acc (10.9%) -0.28 Acc (19.7%) Table 10: Performance gains (BLEU/Accuracy) and token savings (%) evaluated using the Gating (dev-set calibrated) configura- tion. Cell colors represent the percentage of tokens saved. DatasetQwen 3BLlama 3BCommandMistralAyaLlama 8BQwen 32BLlama 70B EMEA (deâen) +0.65 BLEU (15.3%) +0.54 BLEU (23.9%) +0.96 BLEU (14.1%) +0.48 BLEU (9.1%) +0.26 BLEU (22.1%) +0.51 BLEU (35.2%) +0.49 BLEU (26.3%) +0.03 BLEU (12.9%) EMEA (enâde) +0.69 BLEU (27.3%) +0.64 BLEU (22.3%) +0.22 BLEU (6.2%) +0.48 BLEU (56.7%) +0.71 BLEU (35.4%) +0.94 BLEU (24.1%) +0.16 BLEU (17.6%) +0.07 BLEU (5.6%) EMEA (enâes) +0.61 BLEU (25.7%) +0.40 BLEU (45.2%) +0.55 BLEU (17.2%) +0.33 BLEU (21.0%) +0.64 BLEU (48.6%) +1.01 BLEU (38.0%) +0.19 BLEU (22.9%) +0.22 BLEU (17.6%) EMEA (esâen) +0.69 BLEU (33.0%) +0.69 BLEU (31.8%) +1.42 BLEU (38.0%) +0.04 BLEU (4.1%) +0.52 BLEU (4.2%) +0.56 BLEU (33.0%) +0.20 BLEU (26.8%) -0.04 BLEU (20.8%) EMEA (enâpt) +0.94 BLEU (24.0%) +0.25 BLEU (19.0%) +2.53 BLEU (26.3%) +1.85 BLEU (69.1%) +0.64 BLEU (71.5%) +1.74 BLEU (51.6%) +0.66 BLEU (27.2%) +1.44 BLEU (32.4%) EMEA (ptâen) +0.08 BLEU (5.8%) +0.14 BLEU (11.3%) +0.52 BLEU (18.3%) +0.17 BLEU (-0.5%) +0.16 BLEU (-1.1%) +0.15 BLEU (17.5%) +0.27 BLEU (22.6%) +0.12 BLEU (51.3%) JRC-Acquis (deâen) +0.60 BLEU (11.8%) +0.23 BLEU (23.2%) +0.62 BLEU (19.2%) +0.32 BLEU (36.1%) +0.20 BLEU (3.1%) +0.14 BLEU (19.5%) -0.02 BLEU (0.1%) +0.03 BLEU (10.8%) JRC-Acquis (enâde) +0.54 BLEU (21.2%) +0.29 BLEU (22.5%) +0.74 BLEU (34.8%) +0.32 BLEU (4.7%) +0.21 BLEU (19.6%) +0.59 BLEU (30.9%) +0.27 BLEU (21.9%) +0.15 BLEU (11.4%) JRC-Acquis (enâes) +1.05 BLEU (33.9%) +0.58 BLEU (18.0%) +0.31 BLEU (8.9%) +0.59 BLEU (18.2%) +0.17 BLEU (2.3%) +0.28 BLEU (13.3%) +0.27 BLEU (20.8%) +0.32 BLEU (21.7%) JRC-Acquis (esâen) +0.54 BLEU (8.0%) +0.28 BLEU (16.6%) +0.55 BLEU (27.2%) +0.00 BLEU (-5.4%) +0.07 BLEU (9.3%) +0.27 BLEU (36.4%) +0.19 BLEU (17.4%) +0.10 BLEU (10.4%) JRC-Acquis (enâpt) +0.21 BLEU (17.1%) +0.15 BLEU (-2.0%) +0.15 BLEU (14.8%) -0.15 BLEU (-8.1%) -0.03 BLEU (-4.7%) +0.05 BLEU (1.6%) +0.15 BLEU (6.5%) +0.18 BLEU (7.6%) JRC-Acquis (ptâen) -0.00 BLEU (-5.5%) +0.00 BLEU (-5.7%) +0.03 BLEU (2.5%) +0.00 BLEU (-4.9%) +0.00 BLEU (-5.7%) +0.00 BLEU (-5.6%) +0.10 BLEU (3.4%) -0.03 BLEU (4.4%) KDE (deâen) +0.39 BLEU (26.6%) +0.46 BLEU (54.7%) +0.89 BLEU (25.3%) +0.16 BLEU (-1.0%) +0.07 BLEU (6.7%) +0.89 BLEU (22.7%) +0.17 BLEU (14.9%) +0.24 BLEU (18.3%) KDE (enâde) +0.46 BLEU (8.9%) +0.06 BLEU (1.7%) +0.30 BLEU (25.6%) +0.27 BLEU (-3.8%) +0.16 BLEU (-0.3%) +0.21 BLEU (4.0%) +0.16 BLEU (8.0%) +0.11 BLEU (26.6%) KDE (enâes) +0.57 BLEU (25.4%) +0.23 BLEU (15.7%) +0.24 BLEU (13.6%) -0.01 BLEU (-1.7%) +0.12 BLEU (15.9%) +0.16 BLEU (17.4%) +0.04 BLEU (12.2%) +0.10 BLEU (4.9%) KDE (esâen) +0.58 BLEU (21.8%) +0.15 BLEU (14.7%) +0.42 BLEU (28.7%) +0.04 BLEU (-0.3%) +0.19 BLEU (14.4%) +0.28 BLEU (26.6%) +0.09 BLEU (13.9%) +0.32 BLEU (14.2%) KDE (enâpt) +0.52 BLEU (19.8%) +0.43 BLEU (24.3%) +0.27 BLEU (8.9%) +0.10 BLEU (-4.5%) +0.06 BLEU (1.7%) +0.23 BLEU (3.4%) +0.23 BLEU (6.4%) +0.35 BLEU (32.2%) KDE (ptâen) +0.40 BLEU (27.3%) +0.05 BLEU (7.2%) +0.47 BLEU (39.3%) +0.28 BLEU (3.4%) +0.43 BLEU (5.9%) +0.21 BLEU (27.6%) +0.19 BLEU (17.3%) +0.18 BLEU (20.0%) NLU_AgNews +0.35 Acc (84.7%) +0.00 Acc (57.7%) +0.00 Acc (48.9%) +0.00 Acc (77.0%) +0.00 Acc (67.6%) +0.00 Acc (45.0%) +0.00 Acc (-3.4%) +0.00 Acc (-3.5%) NLU_CR +0.90 Acc (85.9%) +2.10 Acc (76.5%) +1.25 Acc (93.2%) +0.85 Acc (81.0%) +0.80 Acc (94.9%) +0.55 Acc (91.1%) +0.85 Acc (93.6%) +0.60 Acc (85.5%) NLU_MNLI +1.00 Acc (37.3%) +1.00 Acc (37.8%) +0.00 Acc (16.0%) +0.00 Acc (-3.4%) +0.00 Acc (-3.5%) +0.00 Acc (45.3%) +0.00 Acc (-3.5%) +0.00 Acc (-3.7%) NLU_QNLI +1.10 Acc (9.9%) +0.10 Acc (-0.3%) +0.00 Acc (2.0%) +1.40 Acc (87.2%) +0.05 Acc (19.3%) +0.00 Acc (8.4%) +0.05 Acc (84.8%) +1.00 Acc (62.2%) NLU_SST-2 +0.10 Acc (53.1%) +0.10 Acc (44.4%) +0.60 Acc (91.5%) +0.30 Acc (53.9%) +0.10 Acc (77.4%) +0.45 Acc (70.1%) +0.80 Acc (94.8%) +0.10 Acc (50.8%) NLU_SST-5 +3.10 Acc (65.2%) +0.05 Acc (40.1%) +1.90 Acc (50.9%) +1.40 Acc (59.6%) +2.55 Acc (61.0%) +2.25 Acc (72.5%) +1.50 Acc (78.9%) +1.80 Acc (65.8%) NLU_Subj +2.00 Acc (65.3%) +0.00 Acc (-3.8%) +0.00 Acc (-3.2%) +4.55 Acc (80.5%) +0.00 Acc (12.1%) +0.00 Acc (-3.5%) +0.00 Acc (-3.7%) +0.00 Acc (-3.9%) Table 11: Performance gains (BLEU/Accuracy) and token savings (%) evaluated using the Gating (test-set calibrated) configura- tion. Cell colors represent the percentage of tokens saved.