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Does high scatter affect the predictive validity of WAIS-III IQs?
Joseph J Ryan1, David S Kreiner, D Bradley Burton
1Department of Psychology, Central Missouri State University, Warrensburg, Missouri 64093, USA.
Applied Neuropsychology
|February 14, 2003
Summary
High scatter on the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) does not impact its IQ scores' ability to predict Wechsler Memory Scale-Third Edition (WMS-III) performance. This finding holds true even when controlling for overall IQ differences.
Area of Science:
- Neuropsychology
- Psychometrics
Background:
- Intersubtest scatter on intelligence tests can raise questions about score validity.
- The Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) and Wechsler Memory Scale-Third Edition (WMS-III) are commonly used cognitive assessments.
Purpose of the Study:
- To investigate whether significant intersubtest scatter on the WAIS-III affects the predictive validity of its IQ scores for WMS-III memory indexes.
- To determine if high scatter compromises the accuracy of WAIS-III in predicting memory performance.
Main Methods:
- Analyzed data from 80 male patients at a Veteran's Administration medical center.
- Compared two groups matched on Full Scale IQ: one with high WAIS-III intersubtest scatter, the other with low scatter.
- Calculated correlations between WAIS-III Full Scale IQ and WMS-III indexes for both groups.
Main Results:
- No significant differences were found in the correlations between WAIS-III Full Scale IQ and WMS-III indexes across high and low scatter groups.
- Regression analyses indicated that the predictive equations for WMS-III indexes were not dependent on the level of WAIS-III intersubtest scatter.
Conclusions:
- The predictive validity of WAIS-III IQ scores for WMS-III memory performance is not compromised by high intersubtest scatter when overall IQ is controlled.
- Further research is recommended with diverse populations and criterion variables to confirm these findings.