Blend: a Novel Combined MT Metric Based on Direct Assessment — CASICT-DCU submission to WMT17 Metrics Task

Existing metrics to evaluate the quality of Machine Translation hypotheses take different perspectives into account. DPM-Fcomb, a metric combining the merits of a range of metrics, achieved the best performance for evaluation of to-English language pairs in the previous two years of WMT Metrics Shared Tasks. This year, we submit a novel combined metric, Blend, to WMT17 Metrics task. Compared to DPMFcomb, Blend includes the following adaptations: i) We use DA human evaluation to guide the training process with a vast reduction in required training data, while still achieving improved performance when evaluated on WMT16 to-English language pairs; ii) We carry out experiments to explore the contribution of metrics incorporated in Blend, in order to find a trade-off between performance and efficiency.