Working memory assessment across editions: a derived index to support continuity of interpretation in the WAIS-5

Objective To develop a derived working memory index based on the WAIS-IV framework that supports continuity of interpretation when using the WAIS-5.Method A psychometric derivation was undertaken using published WAIS-5 subtest correlations and reliability coefficients. Transformation equations were developed to express Digit Span and Arithmetic performance on the standard Wechsler index scale. Reliability, standard error of measurement, and confidence intervals were estimated using classical test theory.Results The derivation produced a working memory index based on the WAIS-IV framework that can be calculated directly from WAIS-5 Digit Span and Arithmetic scaled scores. The resulting index is expressed on the standard Wechsler metric (M = 100, SD = 15), with accompanying estimates of reliability, standard error of measurement, and confidence intervals to support clinical interpretation.Conclusions The derived index provides a practical method for supporting continuity of working memory interpretation across WAIS editions. Although it is not intended to replace the standard WAIS-5 Working Memory Index, it offers clinicians an additional interpretive tool when continuity with earlier editions is desirable.