Investigating Psychometric Properties of Wechsler Memory Scale-Third Edition for the Students of Tehran Universities

The major aim of the present research was investigating psychometric properties of Wechsler Memory Scale-Third Edition (WMS-III) for the students of Tehran Universities. Therefore, this scale was administrated to 266 (120 male, 144 female) students of two universities "Shahed" and "Tarbiat Moallem". The participants were selected through mulitistep cluster sampling. Reliability coefficient of the subtests ranged from 0.65 to 0.85, and for indexes ranged from 0.75 to 0.86. Then, the interscorer agreement of the subtests that needed clinical judgment (such as Logical memory I, II and Family Pictures I, II) was evaluated. The correlation coefficients among scorers was higher than 0/80.The correlation between WMS-III and WAIS-R Short Form was computed for the construct validity which was low. This indicates that WMS-III and WAIS-R short form assessed separate construct although they have significant relations. The intercorrelation between WMS-III subtests and indexes revealed high correlation between modality-specific subtests and indexes, whereas, it has low correlation with other subtests and indexes. Exploratory Factor Analysis (Principle Component Analysis with varimax rotation) was used in order to investigate Factor Structure of WMS-III. The findings obtained showed three factor structures (auditory memory, visual memory and working memory) explain %76/845 of the total variance. These results are similar to previous researches in case of number of factors, on the other hand, this data in subtests of auditory memory was different from the research literature.