The overall entropy for unseen verb distributions also goes down from 2.23 (supervised) to 1.37 (semisupervised), showing that semi-supervised distributions are more peaked, and bringing them closer to the true entropy of the gold distribution (0.93).
using unlabeled data only to estimate parameters that are badly estimated from labeled data (lexical entries in CCG, due to lexical sparsity) results in improvements, in contrast to prior work with semi-supervised EM.