Test-retest reliability of the Wechsler Memory Scale,Form I

Administered the Wechsler Memory Scale, Form I (WMS) twice to 34 normal Ss and 30 hospitalized patients with psychiatric or neurological disorders. In the normal group, the Memory Quotient (MQ) test-retest reliability was r(32) = 0.75, p <0.001. The mean retest gain in points was 7.2, median gain was 7, and range of gain was from −18 to +28. The increase in mean MQ over time was significant, t(33) = 3.95, p < 0.001. In the psychiatric-neurological group, the MQ test-retest reliability was r(28) = 0.89, p <0.001. The mean retest gain in points was 4, median gain was 4.5, and range of gain was from −12 to +23. The increase in mean MQ over time was significant, t(29) = 2.32, p < 0.05. Although the WMS possesses acceptable psychometric reliability, the clinician must keep in mind that the MQ may change significantly over time for individual Ss.