arXiv:2604.03724cs.IR2026-04

用排序代替生成,让推荐解释更真实可信

Rank, Don't Generate: Statement-level Ranking for Explainable Recommendation

  • 将解释生成转为陈述句排序,减少幻觉
  • 在亚马逊数据上验证,个性化排序仍有短板
  • 适合做可解释推荐评估与模型对比的研究者

文本解释日益依赖大语言模型生成以说明推荐理由,但其评估仍具挑战。本文主张从‘生成’转向‘排序’:将可解释推荐建模为陈述句级别的排序问题,从评论中提取候选解释句,按相关性排序并返回前k个作为解释。该方法天然抑制幻觉,支持细粒度事实分析,并可使用标准排名指标进行可复现评估。为确保解释有效性,要求每条陈述具备解释性(关联商品事实与用户体验)、原子性(仅表达一个观点)、唯一性(同义句合并),这在嘈杂评论中难以实现。为此,本文提出基于LLM的抽取流水线与可扩展的语义聚类方法,统一同义表述。在此基础上构建了StaR基准,涵盖四个亚马逊2014年产品类别。评估结果显示,流行度基线在全局排序中表现良好,但在目标商品局部排序中反而优于当前最优模型,暴露出个性化解释排序的核心缺陷。

原文摘要 · Abstract (English)

Textual explanations, generated with large language models (LLMs), are increasingly used to justify recommendations. Yet, evaluating these explanations remains a critical challenge. We advocate a shift in objective: rank, don't generate. We formalize explainable recommendation as a statement-level ranking problem, where systems rank candidate explanatory statements derived from reviews and return the top-k as explanation. This formulation mitigates hallucination by construction and enables fine-grained factual analysis. It also models factor importance through relevance scores and supports standardized, reproducible evaluation with established ranking metrics. Meaningful assessment, however, requires each statement to be explanatory (item facts affecting user experience), atomic (one opinion about one aspect), and unique (paraphrases consolidated), which is challenging to obtain from noisy reviews. We address this with (i) an LLM-based extraction pipeline producing explanatory and atomic statements, and (ii) a scalable, semantic clustering method consolidating paraphrases to enforce uniqueness. Building on this pipeline, we introduce StaR, a benchmark for statement ranking in explainable recommendation, constructed from four Amazon Reviews 2014 product categories. We evaluate popularity-based baselines and state-of-the-art models under global-level (all statements) and item-level (target item statements) ranking. Popularity baselines are competitive in global-level ranking but outperform state-of-the-art models on average in item-level ranking, exposing critical limitations in personalized explanation ranking.

可解释推荐排序模型大模型应用评价基准

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