WMI-Classic (WMI-C) Calculator – WAIS-5

About the WMI-Classic

The WMI-C combines the WAIS-5 Digit Span composite (DSp) and Arithmetic scaled scores to provide a derived working memory index on the standard Wechsler scale (M = 100, SD = 15). It supports continuity with the earlier Digit Span/Arithmetic configuration, but does not replace the official WAIS-5 Working Memory Index.

Based on Skirrow, P., Jayasinghe, I., & Pavlis, A. (in press). Working memory assessment across editions: A derived index to support continuity of interpretation in the WAIS-5. Clinical Psychologist. The accompanying paper includes a WMI-C lookup table and confidence intervals.

Scaled Scores

Digit Span (DSp)

Enter a value between 1 and 19.

Arithmetic (AR)

Enter a value between 1 and 19.

Reliability Coefficients

Use whole-sample averages
DSp = 0.95 · AR = 0.90 Enter age-stratified values
From manual Table B.2, p.57

Using whole-sample average reliabilities: r_DSp = 0.95, r_AR = 0.90. For greater precision, select age-stratified values from Table B.2 (p.57) of the WAIS-5 Technical and Interpretive Manual.

Enter the reliability coefficients for the client's age group from Table B.2 (p.57) of the WAIS-5 Technical and Interpretive Manual.

r_DSp — Digit Span

Whole-sample avg: 0.95

Enter a value between 0 and 1.

r_AR — Arithmetic

Whole-sample avg: 0.90

Enter a value between 0 and 1.

Confidence Interval

95% CI 90% CI

Result

— WMI-C

Reliability

—

r_WMI-C

SEM

—

index score units

Percentile

—

rank

95% Confidence Interval

—

±1.96 × SEM