Refined Measurement of Verbal Learning and Memory: Application of Item Response Theory to California Verbal Learning Test - Second Edition (CVLT-II) Learning Trials

Objective: This study was conducted to investigate how items contained within the California Verbal Learning Test - Second Edition (CVLT-II; Delis, D. C., Kramer, J. H., Kaplan, E., & Ober, B. A. (2000). California Verbal Learning Test (2nd ed.). San Antonio, TX: Psychological Corporation) learning trials function and to evaluate whether weighted scoring approaches might improve quantification of verbal memory. Method: Archival data from 577 individuals (338 healthy young adults, 239 medical or psychiatric patients referred to a neuropsychology clinic) were obtained and evaluated using item response theory. Results: The serial position effect was evident across trials, but was most evident in Trials 1, 2, and 3. CVLT-II Trial 5 was the most effective among the five learning trials in quantifying verbal memory, although it was most effective when measuring lower memory ability levels. In contrast, CVLT-II Trial 1 items had, on average, the highest difficulty levels. Various weighted scoring approaches did not appear incrementally helpful in improving prediction of memory performance. Conclusion: Specific items and trials differentially discriminate between examinees with low levels of memory ability; it is important to thoroughly evaluate item properties of tests used in clinical decision-making.