Precision-recall curves of the evaluated methods. Figure 2 depicts four precision-recall charts plotting interpolated precision values at 11 recall levels. The horizontal axis shows 11 recall points; the vertical axis displays interpolated precision values. A method with a larger area under its curve demonstrates a better result. The differences in performance between LACP, TFIDF and Soft TFIDF are easily apparent. For D1 and D4, LACP consistently outperforms the other two methods. It is important to note, however, that on D2, LACP experiences a rapid precision drop after recall = 0.5, and that on D3, LACP is inferior to most methods.