Automated metrics such as BLEU are widely used in the machine translation literature. They have also been used recently in the dialogue community for evaluating dialogue response generation. However, previous work in dialogue response generation has shown that these metrics do not correlate strongly with human judgment in the non task-oriented dialogue setting. Task-oriented dialogue responses are expressed on narrower domains and exhibit lower diversity. It is thus reasonable to think that these automated metrics would correlate well with human judgment in the task-oriented setting where the generation task consists of translating dialogue acts into a sentence. We conduct an empirical study to confirm whether this is the case. Our findings indicate that these automated metrics have stronger correlation with human judgments in the task-oriented setting compared to what has been observed in the non task-oriented setting. We also observe that these metrics correlate even better for datasets which provide multiple ground truth reference sentences. In addition, we show that some of the currently available corpora for task-oriented language generation can be solved with simple models and advocate for more challenging datasets.

本文考察了在task-oriented对话回复生成中是否能够使用Automated metrics如BLEU准确度较高地评估生成结果。研究表明这些自动化评价指标与人类判断在task-oriented环境中的相关性较高，更适合适用于提供多个参考数据的数据集。同时，本文倡导更具挑战性的数据集的建构。

评估自然语言生成的任务导向对话中无监督度量的相关性