LitBench: A Benchmark and Dataset for Reliable Evaluation of Creative
  Writing
Authors: name: Daniel Fein; name: Sebastian Russo; name: Violet Xiang; name: Kabir Jolly; name: Rafael Rafailov; name: Nick Haber
Published: 2025-07-01 14:10:36

Abstract: Evaluating creative writing generated by large language models (LLMs) remains
challenging because open-ended narratives lack ground truths. Without
performant automated evaluation methods, off-the-shelf (OTS) language models
are employed as zero-shot judges, yet their reliability is unclear in this
context. In pursuit of robust evaluation for creative writing, we introduce
LitBench, the first standardized benchmark and paired dataset for creative
writing verification, comprising a held-out test set of 2,480 debiased,
human-labeled story comparisons drawn from Reddit and a 43,827-pair training
corpus of human preference labels. Using LitBench, we (i) benchmark zero-shot
LLM judges, (ii) train Bradley Terry and generative reward models, and (iii)
conduct an online human study to validate reward model rankings on newly
LLM-generated stories. Our benchmark identifies Claude-3.7-Sonnet as the
strongest off-the-shelf judge, reaching 73% agreement with human preferences;
among trained reward models, Bradley-Terry and Generative reward models both
attain an accuracy of 78%, outperforming all off-the-shelf judges. An online
human study further confirms that our trained reward models consistently align
with human preferences in novel LLM-generated stories. We release LitBench and
reward models at
https://huggingface.co/collections/SAA-Lab/litbench-68267b5da3aafe58f9e43461,
providing a vetted resource for reliable, automated evaluation and optimization
of creative writing systems.