Test-order effects: a measure of verbal memory influences performance on a measure of verbal fluency

In neuropsychological assessment, the impact of completing one measure on the performance of a second measure is often unknown. The current study examined the effect of a list-learning measure, the California Verbal Learning Test-Second Edition (CVLT-II), on a verbal fluency measure, the Delis-Kaplan Executive Functioning System Verbal Fluency subtest, when completed in a battery of tests. These tests were chosen because stimuli from the CVLT-II can function as responses for Verbal Fluency. Twenty-eight individuals seeking psychoeducational evaluation were randomly assigned to one of two test orders: the CVLT-II followed by Verbal Fluency, or the reverse order. Consistent with hypotheses, individuals who completed the CVLT-II first used more words from this task as responses on the various Verbal Fluency tasks, t(26) = 2.84, p = .009. In addition, they obtained higher raw scores and scaled scores on Category Fluency: t(26) = 3.01, p = .006, and t(26) = 2.53, p = .018, respectively. Surprisingly, the larger number of words produced on Category Fluency exceeded the number of CVLT-II words used as responses. These results suggest that clinicians should consider the order of administration when using these measures, and they indicate a need for further investigation of order effects.