Issues In Forensic Psychology - Wechsler Intelligence Scales

ISSUES IN FORENSIC PSYCHOLOGY
Wechsler Intelligence Scales

The Wechsler scales are the most frequently used tests for the assessment of general intellectual ability.
There are three separate versions of these scales developed for different age groups: (1) The Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R) is used with children between the ages of 3 and 7, (2) The Wechsler Intelligence Scale for Children-Third Edition (WISC-III) is used with children between the ages of 8 and 17, and (3) The Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) is used with subjects 18 years of age and older.
Each of the Wechsler scales reports three IQ scores: (1) Verbal IQ, (2) Performance IQ, and (3) Full Scale IQ.
Interpreting the Wechsler scales presumes they have been administered in a standardized manner. Unfortunately, however, the relevant research demonstrates that psychologists frequently commit administration errors when using the Wechsler scales. These administration errors compromise the accuracy of the results obtained from the Wechsler scales.
Psychologists also freqently assign unwarranted significance to variations between Verbal IQ and Performance IQ. Except for extreme differences between Verbal IQ and Peformance IQ, the relevant research contraindicates this practice.
Too many psychologists make conclusions regarding brain damage based on one of the Wechsler scales alone, or in combination with a gross screening device. The relevant research also contraindicates this practice.
For minority groups, Full Scale IQ scores can vary substantially depending on the ethnicity of psychologist administering the Wechsler scales.

If you would like more information regarding the Wechsler Scales, you may want to order the following publication authored by Dr. Campbell.

"Cross-Examining Psychologists and Psychiatrists as Expert Witnesses." This is a 79-page, single-spaced outline, containing 214 footnoted references. This outline is bound. (Order article #15, cost $59.00).

Home Page | Available Publications | Curriculum Vitae | Professional History