Figure 5. The receiver operating characteristic (ROC) curves of SNPs called by FREEBAYES and SAMTOOLS.

The points on the curves are sorted by called qualities and the points closer to the upper-right corner have higher called qualities. The true positive (TP), false positive (FP), and false negative (FN) are calculated by intersecting SNPs called on each aligner's alignments and gold SNPs called on the simulated alignments.