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arXiv 1807.02202cs.CL
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自然语言评测中自动度量去偏的代价

The price of debiasing automatic metrics in natural language evaluation

Stanford University(斯坦福大学)

Arun Tejasvi Chaganty, Stephen Mussman, Percy Liang

摘要:

为了评估发电系统,BLEU等自动指标运行起来没有任何成本,但已被证明与人类判断相关性很差,导致对某些模型改进的系统性偏见。另一方面,平均人类的判断,无偏见的黄金标准,往往过于昂贵。在本文中,我们使用控制变量结合自动度量与人类的评价,以获得一个无偏估计比人类的评价成本更低。然而,在实践中,我们在评估摘要和开放式应答问答系统上仅获得7-13%的成本降低。然后,我们证明我们的估计是最优的:没有无偏估计具有较低的成本。我们的理论进一步强调了两个基本瓶颈-自动度量和显示给人类评估者的提示-这两者都需要改进以获得更大的成本节约。

英文摘要:

For evaluating generation systems, automatic metrics such as BLEU cost nothing to run but have been shown to correlate poorly with human judgment, leading to systematic bias against certain model improvements. On the other hand, averaging human judgments, the unbiased gold standard, is often too expensive. In this paper, we use control variates to combine automatic metrics with human evaluation to obtain an unbiased estimator with lower cost than human evaluation alone. In practice, however, we obtain only a 7-13% cost reduction on evaluating summarization and open-response question answering systems. We then prove that our estimator is optimal: there is no unbiased estimator with lower cost. Our theory further highlights the two fundamental bottlenecks---the automatic metric and the prompt shown to human evaluators---both of which need to be improved to obtain greater cost savings.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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