Abstract
In this article, the authors compare the assay performance measures, signalwindow, Z' factor, and assay variability ratio. They examine their mathematical formulae for similarities and differences, describe their statistical sampling properties using the results of a computer simulation, and illustrate their usewith example data. Based on these results, the authors recommend the Z' factor as a preferredmeasure of assay performance for screening assays and point out that none of thesemeasures are adequate for characterizing concentration-response assays.
