qvality - Nonparametric estimation of posterior error probabilities
qvality estimates q-values and posterior error probabilities directly from score distributions.
The method can be accessed via a web interface or downloaded as part of the Percolator package.
If you use this software in your research, please cite
Lukas Käll, John D. Storey and William Stafford Noble. "qvality: Nonparametric estimation of q values and posterior error probabilities" Bioinformatics, 25(7):964-966, February 2009The nonparametric regression procedure is described in more detail in this paper:
Lukas Käll, John D. Storey and William Stafford Noble. "Nonparametric estimation of posterior error probabilities associated with peptides identified by tandem mass spectrometry." Bioinformatics, 24(16):i42-i48, August 2008