The features for quality estimation should reflect the complexity of the source sentence and the decoding process.
we conduct syntactic analysis on the source sentences, extract features from the decoding process and select the following 26 features: • 17 decoding features, including phrase translation probabilities (source-to-target and target-to-source), word translation probabilities (also in both directions), maxent probabilities 1 , word count, phrase count, distor-tion probabilities, as well as a set of language model scores.