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.
- 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