Practitioner’s Guide to Evaluating Change with Intellectual Assessment Instruments

While conducting research on intellectual and neuropsychological perfonnance of various patient populations across time, we became aware of the lack of information concerning practice effects associated with many widely used assessment instruments. Although test-retest data were available for almost all of these instruments, it typically came in the form of correlation coefficients and mean changes in performance between assessments was often absent. In a 1995 article (McCaffrey & Westervelt