Example showing how the inclusion of other parameters can improve sensitivity in a decoy DB approach. For a FDR = 0, just three identifications can be retrieved when applying Xcorr thresholds. The addition of ΔCn allows threshold combinations resulting in five identifications (rectangles and ellipses). (a) Textual representation. (b) Graphical representation (ΔCn vs. Xcorr), where crosses represent decoy PSMs and circles denote normal PSMs. We added here the green curve in (b) to show that a non-linear decision boundary is expected to further enhance sensitivity in such analysis.
Cerqueira et al. BMC Genomics 2012 13(Suppl 5):S4 doi:10.1186/1471-2164-13-S5-S4