Since the WAIS-III was published, four exploratory factor-analytic studies have
examined its structure. Saklofske, Hildebrand, and Gorsuch (2000) studied a Canadian,
non-clinical sample; Kaufman, Lichtenberger, and McLean (2001) examined the
standardization sample; Ryan and Paulo (2001) studied a mixed-patient sample; and
Dickinson, Iannone, and Gold (2002) examined the factor structure in individuals with
schizophrenia. All four of these studies replicated the four-factor structure, which
suggests that it is very robust across a range of samples. The replication of this structure
offers clinicians and researchers increased confidence when using the scale with
individuals from specific samples.
The current study, therefore, aims to investigate the factor structure of the WAIS-III
with a low IQ population, in order to assess whether the factor structure is the same as
that of the standardization sample.