All of the metrics take two inputs: M and C, where M is a workload sen-tence from the MTBT (Material To Be Translated) and C is the source language side of a candidate pre-existing translation from the TM bank.
observing the scatterplots for ED and those for MWNGP one can see that both methods have the vast majority of points concentrated in the lower left and upper right quadrants, solving the upper left quadrant problem of PM.