Clinical Psychology

children ages 6 through 16 years, the WISC-IV con-
sists of ten core and five supplementary subtests. Like
its predecessors, the WISC-IV is in many ways a
downward extension of the Wechsler adult intelli-
gence scales (Zhu & Weiss, 2005).

Description. The WISC-IV has a hierarchical
structure in which individual subtests define
four major indices that comprise the Full Scale
IQ. Figure 7-6 presents this model.

1. TheVerbal Comprehension Index (VCI)includes
   the Similarities, Vocabulary, and Comprehen-
   sion subtests; Information and Word Reason-
   ing are the supplementary VCI subtests. The
   VCI is an index of verbal reasoning and
   comprehension.
   2. ThePerceptual Reasoning Index (PRI)consists of
   the Block Design, Picture Concepts, and
   Matrix Reasoning subtests, whereas the Picture
   Completion subtest is now a supplemental
   subtest for the PRI. The PRI is similar to the
   Performance IQ index used in older Wechsler
   tests except there is much less emphasis on
   speeded performance and on motor skill.
   3. TheWorking Memory Index (WMI)consists of
   the Digit Span and Letter-Number Sequencing
   subtests, and the Arithmetic subtest is now used
   as a supplemental subtest for the WMI. The
   WMI is similar to the WISC-III’s (Wechsler,
   1991) Freedom from Distractibility Index, and
   the WMI measures a child’s ability to hold
   information in consciousness, perform some

T A B L E 7-4 WAIS-IV Subtests and Their Respective IQ or Index Scores

IQ Score or Index Score

Full Scale

IQ

Verbal

Comprehension

Perceptual

Reasoning

Working

Memory

Processing

Speed

Subtest

Vocabulary √√

Coding √ √

Similarities √√

Block Design √√

Arithmetic √√

Matrix Reasoning √√

Digit Span √√

Information √√

Picture Completion O

Comprehension O

Figure Weights O
Symbol Search √ √

Visual Puzzles √√

Letter-Number Sequencing O

Cancellation O

NOTE:√indicates that scaled scores for the respective subtest are used to calculate that IQ score or Index score. O indicates that scaled scores for the respec-
tive subtest can be used in place of specified Index subtests if they are not administered.

210 CHAPTER 7