ROC graphs plotting true (y-axis) and false (x-axis) positive rates for seven character trimming methods. The best methods (i.e., that minimize both the number of true negative and false positive characters) are those with the corresponding cloud concentrated around the upper left point (0,1). Under each ROC graph, the average L1 distance between each point and the (0,1) point is given. For each level of divergence, the best (i.e. lower) distance is written in boldface characters. Average L1 distances that are not significantly different to this best value (as assessed by a sign test) are underscored.