Test Performance Variation Between Settings and Populations

The present paper is the third in a series on the evaluation of new tests designed to detect the disordered gambler. The present paper has two objectives. First, the observed variation in test performance between settings and populations is described in general terms and an explanation of the observed variation is presented in terms of what is referred to as spectrum effects. Second the expected variation in test performance between settings and populations is illustrated with several examples and the implications emphasized for the purpose of test evaluation.