@inproceedings{gong-etal-2026-dseffi,
title = "{DSE}ffi-Bench: Demystifying Large Language Models' Capability in Efficient Data Science Code Generation",
author = "Gong, Zhihao and
Yu, Junzhe and
Huang, Dong and
Sun, Zeyu and
Zhang, Jie M. and
Hao, Dan",
editor = "Lee, Hung-Yi and
Dev, Sunipa and
Li, Jessy and
Elliott, Desmond",
booktitle = "Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing",
month = oct,
year = "2026",
address = "Budapest, Hungary",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.emnlp-main.318/",
pages = "7337--7372",
ISBN = "979-8-89176-459-0",
abstract = "Current data science (DS) code generation benchmarks equate correctness with quality, overlooking execution time differences that span orders of magnitude between correct solutions. We introduce DSEffi-Bench, the first benchmark specifically targeting execution efficiency in LLM-generated DS code, comprising 1,000 instances across 10+ DS libraries with stress-testing harnesses and human-validated references. Evaluating 16 models across 3 tiers, we find that correctness alone fails to characterize efficiency: GPT-5.4 leads in correctness (Pass, 66.9{\%}) but its efficiency score (B|P, 71.7{\%}) nearly matches GPT-5.4-mini (71.6{\%}), which solves 47 fewer tasks; Kimi-K2.5 ranks lowest in correctness among frontier models (40.2{\%}) yet achieves the highest efficiency score (73.6{\%}) across all 16 models. A human-annotated five-category taxonomy reveals that 79.1{\%} of efficiency deficits extend beyond algorithmic complexity to domain-specific root causes, with distinct failure profiles across model tiers and libraries. Two exploratory experiments provide initial evidence that these diagnostics can guide improvement, yielding up to +14.7{\%} efficiency gains via taxonomy-guided optimization and approaching Claude-Opus-4.6 Best@3 in efficiency at 13.0{\texttimes} lower cost via library-conditioned routing. Code and data are available at https://github.com/Albert-Gong/DSEffi-Bench."
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<abstract>Current data science (DS) code generation benchmarks equate correctness with quality, overlooking execution time differences that span orders of magnitude between correct solutions. We introduce DSEffi-Bench, the first benchmark specifically targeting execution efficiency in LLM-generated DS code, comprising 1,000 instances across 10+ DS libraries with stress-testing harnesses and human-validated references. Evaluating 16 models across 3 tiers, we find that correctness alone fails to characterize efficiency: GPT-5.4 leads in correctness (Pass, 66.9%) but its efficiency score (B|P, 71.7%) nearly matches GPT-5.4-mini (71.6%), which solves 47 fewer tasks; Kimi-K2.5 ranks lowest in correctness among frontier models (40.2%) yet achieves the highest efficiency score (73.6%) across all 16 models. A human-annotated five-category taxonomy reveals that 79.1% of efficiency deficits extend beyond algorithmic complexity to domain-specific root causes, with distinct failure profiles across model tiers and libraries. Two exploratory experiments provide initial evidence that these diagnostics can guide improvement, yielding up to +14.7% efficiency gains via taxonomy-guided optimization and approaching Claude-Opus-4.6 Best@3 in efficiency at 13.0× lower cost via library-conditioned routing. Code and data are available at https://github.com/Albert-Gong/DSEffi-Bench.</abstract>
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%0 Conference Proceedings
%T DSEffi-Bench: Demystifying Large Language Models’ Capability in Efficient Data Science Code Generation
%A Gong, Zhihao
%A Yu, Junzhe
%A Huang, Dong
%A Sun, Zeyu
%A Zhang, Jie M.
%A Hao, Dan
%Y Lee, Hung-Yi
%Y Dev, Sunipa
%Y Li, Jessy
%Y Elliott, Desmond
%S Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
%D 2026
%8 October
%I Association for Computational Linguistics
%C Budapest, Hungary
%@ 979-8-89176-459-0
%F gong-etal-2026-dseffi
%X Current data science (DS) code generation benchmarks equate correctness with quality, overlooking execution time differences that span orders of magnitude between correct solutions. We introduce DSEffi-Bench, the first benchmark specifically targeting execution efficiency in LLM-generated DS code, comprising 1,000 instances across 10+ DS libraries with stress-testing harnesses and human-validated references. Evaluating 16 models across 3 tiers, we find that correctness alone fails to characterize efficiency: GPT-5.4 leads in correctness (Pass, 66.9%) but its efficiency score (B|P, 71.7%) nearly matches GPT-5.4-mini (71.6%), which solves 47 fewer tasks; Kimi-K2.5 ranks lowest in correctness among frontier models (40.2%) yet achieves the highest efficiency score (73.6%) across all 16 models. A human-annotated five-category taxonomy reveals that 79.1% of efficiency deficits extend beyond algorithmic complexity to domain-specific root causes, with distinct failure profiles across model tiers and libraries. Two exploratory experiments provide initial evidence that these diagnostics can guide improvement, yielding up to +14.7% efficiency gains via taxonomy-guided optimization and approaching Claude-Opus-4.6 Best@3 in efficiency at 13.0× lower cost via library-conditioned routing. Code and data are available at https://github.com/Albert-Gong/DSEffi-Bench.
%U https://aclanthology.org/2026.emnlp-main.318/
%P 7337-7372
Markdown (Informal)
[DSEffi-Bench: Demystifying Large Language Models’ Capability in Efficient Data Science Code Generation](https://aclanthology.org/2026.emnlp-main.318/) (Gong et al., EMNLP 2026)
ACL