Index scores provide a more detailed evaluation of
the examinee’s strengths and weaknesses across tasks.
Following are brief descriptions of the 15 WAIS-
IV subtests, with the corresponding Index scale to
which the subtest belongs indicated in parentheses.
1.Vocabulary (Verbal Comprehension). Here, the
examinee must define words that increase in
difficulty. This subtest correlates highly with
Full Scale IQ, and some feel that it comes close
to measuring what is usually termedg.
2.Similarities (Verbal Comprehension). This subtest
consists of a series of items, and for each one,
the examinee must explain how two objects
are alike. The subtest requires the basic ability
to form abstractions and develop concepts.
3.Arithmetic (Working Memory). These items are
similar to arithmetic problems that appear in
most school textbooks. The items are admin-
istered orally, and the examinee is not allowed
to use paper and pencil.
4.Digit Span (Working Memory). This subtest is a
measure of short-term memory and attention.
Three sets of digits are read aloud by the examiner.
Forthefirstlist,theexamineemustrepeatthedigits
in the order that they were read. For the second
list, the digits must be repeated backward. Finally,
for the third list, the digits must be repeated back to
the examiner in ascending order.
5.Information (Verbal Comprehension). These short
questions tap knowledge that one would be
expected to have acquired as a result of every-
day living and cultural interactions.
6.Comprehension (Verbal Comprehension, supple-
mental subtest). The items of this subtest require
the examinee to explain why certain proce-
dures are followed, to interpret proverbs, and
to determine what should be done in a given
situation. The items measure common sense
and practical judgment in solving a problem.
This is a supplementary subtest for IQ scores.
7.Letter-Number Sequencing (Working Memory,
supplemental subtest). This subtest consists of
items that assess working memory and atten-
tion. A combination of numbers and letters isread, and the examinee must first recall the
numbers in ascending order and then the letters
in alphabetical order. Each item consists of
three trials of different combinations of num-
bers and letters. This is a supplementary subtest
for IQ scores.
8.Picture Completion (Perceptual Reasoning, supple-
mental subtest). This subtest consists of colored
cards, each showing a picture with a part
missing. The examinee must identify the
missing part. This requires concentration and
the ability to note details and incongruities.
This is a supplementary subtest for IQ scores.
9.Coding (Processing Speed). This code-substitution
task requires the examinee to fill in the
appropriate code in the blanks under a long
series of numbers, using a key. The subtest
requires the examinee to work in a direct,
single-minded fashion.
10.Block Design (Perceptual Reasoning). The exam-
inee must assemble up to nine blocks to match
the designs on a set of cards. The task involves
visual-motor coordination and analytic syn-
thesizing ability.
11.Matrix Reasoning (Perceptual Reasoning). This sub-
test consists of items that measure visual infor-
mation processing and abstract reasoning skills.
12.Symbol Search (Processing Speed). This subtest
consists of items that ask the respondent to
indicate whether a stimulus symbol appears in
the array that is present.
13.Visual Puzzles (Perceptual Reasoning).This new
subtest requires the examinee to choose from a
list correct pieces of a puzzle that when placed
together reconstruct the puzzle picture that is
presented.
14.Figure Weights (Perceptual Reasoning, supplemental
subtest).This new subtest asks the examinee to
look at a two-dimensional representation of a
scale with missing weights and then select the
weights necessary to keep the scale balanced.
This is a supplementary subtest for IQ scores.
15.Cancellation (Processing Speed, supplemental sub-
test).This new subtest requires the examinee to208 CHAPTER 7