Purpose: Designed to measure intellectual abilities and academic achievement.
Population: Children, aged 2:6 years through 7:3 years.
Scales: Verbal, Performance, Full Scale IQS, Processing Speed Quotient, and General Language Composite
Time: 30-35 minutes for children aged 2:6-3:11 and 40-50 minutes for ages 4-7:11.
Author: David Wechsler
Publisher: The Psychological Corporation
Description: The Wechsler Preschool and Primary Scale of Intelligence - Third Edition is a revision of the WPPSI-R and has extended the age range, updated the norms, added new subtests and composite scores, and claims to have a developmentally appropriate structure based on contemporary intelligence and cognitive development theory. The artwork has been updated, and some the test material has been made more child-friendly and engaging. Some modifications in the administration and scoring make the scales easier to use.
Scoring: The WPPSI-III contains 4 core subtests for ages 2:6 to 3:11; Receptive Vocabulary, Information, (VIQ) Block Design, Object Assembly (PIQ), and 7 for ages 4:0 to 7:3; Information, Vocabulary, Word Reasoning (VIQ), Block Design, Matrix Reasoning, Picture Concepts (PIQ), and Coding (FSIQ). Supplemental tests for 2:6 to 3:11 group are Picture naming and Receptive Vocabulary (GLC). For the 4 to 7:3 group the supplementary tests are Symbol Search, Comprehension, Picture Completion, Similarities, Object Assembly (PSQ), and the optional subtests are Receptive Vocabulary and Picture Naming (GLC). The WPPSI-III employs the Deviation IQ (M=100, SD=15) for the Verbal, Performance and Full Scale IQS, and scaled scores (M=100, SD=3) for the subtests
Reliability: The reliability coefficient of the WPPSI-III subtests range from .83 to .95. The reliability coefficients for the composite scales ranged from .89 to .96. Test-retest reliabilities for a mean interval of 26 days for the 2:6 to 3:11 year old group Verbal, Performance, Full and General Language scores were .90, .84, .92 and .92 respectively. For the 4 to 7:3 year old group for Verbal, Performance, Processing Speed, Full and General Language werer.92, .87, .93, .92, and .90 respectively.
Validity: The evidence of previous research that because of the similarity of content, much of the research on the validity of the WPPSI- R The scores derived from the WPPSI-R correlate well with the WPPSI, WISC-R, Stanford Binet (4th ed.), and McCarthy Scales (rs between WPPSI-R FSIQs and other test composites range from .74 to .90). The correlation between the WPPSI-R FSIQ and the Kaufman-Assessment Battery for Children (K-ABC) Mental Processing Composite is low (.49), but the K-ABC has consistently yielded lower correlations with other intelligence tests as well. These results imply good criterion validity for the WPPSI-R. There are also studies showing the discriminant validity of the WPPSI-R with gifted, mentally deficient, learning disabled, and speech-language impaired children.
Norms: The normative sample included 1700 children in nine age groups. The sample was representative of the US population of children aged 2:6 to 7:3 for sex, race/ethnicity, parental education level and geographic region.
Suggested use: The WPPSI-III for assessment of general intellectual functioning as part of an assessment to identify giftedness, delays, or mental retardation. Results can be useful in guiding clinical or school related placements.