Retrieval performance for the (FQPS) statstics. ROC curves (true positive rate vs. false positive rate) when searching TM proteins from the ASTRAL reference set against the complete ASTRAL set. Different symbols indicate different p-value thresholds being used. Inset: sensitivity for (FQPS) compared with BLAST search. The plot shows the averaged number of observed helical proteins as a function of the rank in the result set.