Intelligence tests Wechsler Tests Info on David Wechsler

Intelligence tests Wechsler Tests Info on David Wechsler

Wechsler Adult Intelligence Scale – WAIS Original in 1939 – W-B I n WAIS-IV - 2008 n Ages 16 through 90 n

Wechsler Intelligence Scale for Children WISC Original in 1949 n Ages 6 through 16 n WISC-R in 1974 n WISC-IV in 2003 n

Wechsler Preschool and Primary Scale of Intelligence WPPSI Original in 1963 n Ages 3 to 7 years n WPPSI-III in 2002 n

Common features of Wechsler tests Full Scale IQ n 2 major second level categories n 12 – 15 subtests n Individually administered n 50 -70 minutes administration time n Normative data n Comprehensive manuals n

Revisions: More contemporary – words, pictures, terms n More culture free n Better norms n More theoretical base (CHC model) Link to information on CHC model n

Cattell-Horn-Carroll (CHC) model General factor of intelligence (g) n Started with Gf-Gc theory (fluid/crystallized) n Specific abilities (number varies) n

CHC model

Test scores n Full Scale IQ Verbal Comprehension index Perceptual Reasoning index Working Memory index Processing Speed index

Sub-tests n n n n Picture completion Information Coding Similarities Picture arrangement Arithmetic Block design Vocabulary Object assembly Comprehension Symbol search Digit span Mazes

WAIS - IV

Psychometrics n Reliability - Internal consistency u Verbal =. 97 u Performance =. 93 u Split half =. 95 n Validity – multi-trait u High correlation with Binet

Web info on WISC IV Model of WISC IV n Psychometrics of WISC IV n