If we plot the precision-recall graphs using purity to classify sentences -as opposed to the vote-flip algorithm, which only provides an unweighted classification -we can see that at almost all recall levels the web-derived lexicon has superior precision to the other lexicons (Figure 4).
even though the web-derived lexicon is constructed from a lexical graph that contains noise, the graph propagation algorithms appear to be fairly robust to this noise and are capable of producing large and accurate polarity lexicons.