Date of Submission


Degree Type


Degree Name

Doctor of Psychology (PsyD)



Department Chair

Robert A DiTomasso, PhD, ABPP

First Advisor

George McCloskey, PhD


The current study was designed to examine the appropriateness and effectiveness of a neuropsychologically based performance consistency model in comparison to traditional psychometric conceptualizations of reliability when examining test-retest performance on the Wechsler Adult Intelligence Scale – Third Edition (WAIS–III). Regardless of whether the sample was grouped by total sample or in reference to subject performance to the mean, an overall progression effect rather than regression to the mean was noted. When grouping subjects in terms of their relation to the mean, a poor goodness of fit obtained via chi-square analysis was found between traditional psychometric reliability estimates and actual results obtained via the performance consistency model. These findings are discussed in terms of the clinical utility of viewing changes in test-retest performance as potentially meaningful indicators of changes in cognitive functioning. This calls into question the appropriateness of previous research, which has typically eschewed the practice of subtest level interpretation of cognitive processing.