Figure 2
From: Using quality scores and longer reads improves accuracy of Solexa read mapping

Mapping accuracy of RMAPQ criterion under varying parameters. Reads with length from 25–36 nt were mapped and 0,1, or 2 mismatches were allowed at high quality bases defined by quality score cutoffs of 4 (d) or 8 (a-d). For reference, mapping performance of RMAPM criterion with at most 2 mismatches is also shown. (a) The BAC coverage; (b) the mapping selectivity; (c) the overall mapping accuracy (equal to the mean of the BAC coverage and selectivity).(d) 2-D performance comparison in both BAC coverage and selectivity of RMAPM and RMAPQ.