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Main Authors: Nagl, Sebastian, Mayrhofer, Ann-Kristin, Heidebach, Martin, Koçak, Aleyna, Zettelmeier, Anne, Breu, Elly, Greiner, Angelina, Milijas, Sofija, Grabmair, Matthias
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2605.28183
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author Nagl, Sebastian
Mayrhofer, Ann-Kristin
Heidebach, Martin
Koçak, Aleyna
Zettelmeier, Anne
Breu, Elly
Greiner, Angelina
Milijas, Sofija
Grabmair, Matthias
author_facet Nagl, Sebastian
Mayrhofer, Ann-Kristin
Heidebach, Martin
Koçak, Aleyna
Zettelmeier, Anne
Breu, Elly
Greiner, Angelina
Milijas, Sofija
Grabmair, Matthias
contents We introduce the BenGER (Benchmark for German Law) dataset for evaluating LLM systems on subsumption-based legal reasoning in German law. The BenGER dataset consists of three components: 596 exam-style free-text legal case tasks across multiple levels of legal education and 531 short doctrinal reasoning tasks. We evaluate 12 contemporary LLM systems -- closed flagship, efficiency-oriented, and open-weight -- across automatic and judge-based metrics. On a controlled validation subset of timed human-written solutions under both unaided and human--AI co-creation conditions, we contextualise model performance against these human baselines. We introduce a rubric-aligned LLM-as-a-Judge framework cross-validated against a multi-rater human-grading protocol (three blind reviews plus one author-informed creator review per solution). Our results show that replacing a blind human reviewer with the LLM judge degrades agreement with the full human pool no more than removing that reviewer altogether (Calderon r=0.96 vs.~r=0.96, matched n=30), that closed-flagship systems lead the leaderboard across all corpora, and that human--AI co-creation substantially outperforms unaided human work.
format Preprint
id arxiv_https___arxiv_org_abs_2605_28183
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle BenGER: Benchmarking LLM Systems on Subsumption-Based Legal Reasoning in German Law
Nagl, Sebastian
Mayrhofer, Ann-Kristin
Heidebach, Martin
Koçak, Aleyna
Zettelmeier, Anne
Breu, Elly
Greiner, Angelina
Milijas, Sofija
Grabmair, Matthias
Computation and Language
Artificial Intelligence
We introduce the BenGER (Benchmark for German Law) dataset for evaluating LLM systems on subsumption-based legal reasoning in German law. The BenGER dataset consists of three components: 596 exam-style free-text legal case tasks across multiple levels of legal education and 531 short doctrinal reasoning tasks. We evaluate 12 contemporary LLM systems -- closed flagship, efficiency-oriented, and open-weight -- across automatic and judge-based metrics. On a controlled validation subset of timed human-written solutions under both unaided and human--AI co-creation conditions, we contextualise model performance against these human baselines. We introduce a rubric-aligned LLM-as-a-Judge framework cross-validated against a multi-rater human-grading protocol (three blind reviews plus one author-informed creator review per solution). Our results show that replacing a blind human reviewer with the LLM judge degrades agreement with the full human pool no more than removing that reviewer altogether (Calderon r=0.96 vs.~r=0.96, matched n=30), that closed-flagship systems lead the leaderboard across all corpora, and that human--AI co-creation substantially outperforms unaided human work.
title BenGER: Benchmarking LLM Systems on Subsumption-Based Legal Reasoning in German Law
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2605.28183