WAIS-R item difficulties with psychiatric inpatients

Area of Science:

• Psychology
• Psychometrics
• Clinical Psychology

Background:

• The Wechsler Adult Intelligence Scale–Revised (WAIS-R) is a widely used cognitive assessment tool.
• Understanding how item difficulty manifests in specific clinical populations, such as psychiatric inpatients, is crucial for accurate interpretation.

Purpose of the Study:

• To determine the item difficulties for 10 WAIS-R subtests in a sample of psychiatric inpatients.
• To compare the rank order of item difficulties between psychiatric inpatients and the standardization group for the WAIS-R.

Main Methods:

• Item difficulties for 10 WAIS-R subtests were calculated for 150 psychiatric inpatients.
• Spearman correlation coefficients were used to compare rank orders between the inpatient and standardization groups.
• Linear regression identified items significantly out of order based on standardized residuals.

Main Results:

• Spearman correlations were large and significant for most subtests, indicating similar item difficulty rank orders.
• The Object Assembly subtest showed an expected increase in item difficulty for the inpatient sample.
• Only 7 out of 165 WAIS-R items were found to be significantly out of order for psychiatric inpatients.

Conclusions:

• WAIS-R subtest item difficulty curves are generally comparable between psychiatric inpatients and the standardization group.
• Minor deviations in item order are likely due to chance and do not significantly impact overall test structure in this population.