Papers › On the Evaluation Metrics for Paraphrase Generation

On the Evaluation Metrics for Paraphrase Generation

17 Feb 2022arXiv:2202.08479archive 2025-07-28

Lingfeng Shen, Lemao Liu, Haiyun Jiang, Shuming Shi

In this paper we revisit automatic metrics for paraphrase evaluation and obtain two findings that disobey conventional wisdom: (1) Reference-free metrics achieve better performance than their reference-based counterparts. (2) Most commonly used metrics do not align well with human annotation. Underlying reasons behind the above findings are explored through additional experiments and in-depth analyses. Based on the experiments and analyses, we propose ParaScore, a new evaluation metric for paraphrase generation. It possesses the merits of reference-based and reference-free metrics and explicitly models lexical divergence. Experimental results demonstrate that ParaScore significantly outperforms existing metrics.

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