Characterising the performance of qualitative analytical methods: Statistics and terminology

This article presents an overview of statistical methods used in validation and proficiency testing for qualitative testing in analytical chemistry, paying particular attention to interlaboratory study. A definition of “qualitative analysis” that allows a general treatment of a wide variety of different examples is used. We discuss the characterisation of qualitative method performance, and consider in detail methods for the analysis of false response rates. We review appropriate statistical methods for a variety of circumstances, including the application of logistic regression to interlaboratory and intralaboratory studies of method performance. Finally, we propose provisional recommendations for the design and statistical treatment of validation and proficiency studies.