A Systematic Comparison of Smoothing Techniques for Sentence-Level BLEU
Boxing Chen, Colin Cherry · 2014
BLEU is the de facto standard machine translation (MT) evaluation metric.However, because BLEU computes a geometric mean of n-gram precisions, it often correlates poorly with human judgment on the sentence-level.Therefore, several smoothing techniques have been proposed.This paper systematically compares 7 smoothing techniques for sentence-level BLEU.Three of them are first proposed in this paper, and they correlate better with human judgments on the sentence-level than other smoothing techniques.Moreover, we also compare the performance of using the 7 smoothing techniques in statistical machine translation tuning.