They test their method over three different corpora, with results ranging from a precision of 0.21 and recall of 0.86 (F-score=0.34) for the smallest corpus, to a precision of 0.03 and recall of 0.85 (F-score=0.06) for the largest corpus.
high levels of noise are evident in the system output, and the F-score values are well below those achieved by our method for English VPCs.