The Wechsler Preschool and Primary Scale of Intelligence (WPPSI) is an intelligence test designed for children ages 2 years 6 months to 7 years 3 months developed by David Wechsler in 1967. It is a descendent of the earlier Wechsler Adult Intelligence Scale and the Wechsler Intelligence Scale for Children tests.
It has since been revised twice, in 1989 and 2002.
The current revision, WPPSI–III, is published by Harcourt Assessment. It provides subtest and composite scores that represent intellectual functioning in verbal and performance cognitive domains, as well as providing a composite score that represents a child’s general intellectual ability (i.e., Full Scale IQ).
Some studies show that intelligence tests such as the WPPSI-III, especially for pre-K level, are unreliable and their results vary wildly with various factors such as retesting, practice (familiarization), test administrator, time and place. There are claims that some commercially available material improve results simply by eliminating negative factors through familiarization which in turn puts children at a comfortable frame of mind.