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) = .75, p less than .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 less than .001. In the psychiatric-neurological group, the MQ test-retest reliability was r(28) = .89, p less than .001. The mean retest gain 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 less than .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.