APPENDIX 3: WAIS-IV SUBTEST DESCRIPTIONS
The General Ability Index (GAI) is an optional summary score that is less sensitive to the influence of working memory
and processing speed. As working memory and processing speed are vital to a comprehensive evaluation of cognitive
ability, it should be noted that the GAI does not have the breadth of coverage as the FSIQ. The GAI should be interpreted
with caution if there is a 15+ difference between the VCI and PRI.
The Full-Scale IQ (FSIQ) score is the overall score that estimates an individual’s general level of intellectual functioning.
It is usually considered to be the score that is most representative of global intellectual functioning. The FSIQ should be
interpreted with caution if there is a one or more standard deviation (15+) difference between the VCI, PRI, WMI. or PSI.
VERBAL
COMPREHENSION
INDEX
The Verbal Comprehension Index (VCI) is a measure of verbal acquired knowledge and verbal
reasoning incorporating the 3 core Verbal subtests of Information, Similarities, and Vocabulary
and one supplemental subtest Comprehension.
Vocabulary The Vocabulary subtest required the individual to explain the meaning of words presented in
isolation, both visually and orally. As a direct assessment of word knowledge, the subtest is one
indication of their overall verbal comprehension and fund of knowledge. Performance on this
subtest also requires abilities to verbalise meaningful concepts as well as to retrieve information
Similarities On the Similarities subtest, the individual was required to respond orally to a series of word pairs
by explaining the similarity of the common objects or concepts they represent. This subtest
examines their ability to abstract meaningful concepts and relationships from verbally presented
material. As well as involving crystallised intelligence, abstract reasoning, auditory comprehension,
memory, associative and categorical thinking, distinction between nonessential and essential
features and verbal expression.
Information The Information subtest required the individual to respond verbally to a series of orally presented
questions that assess knowledge about common events, objects, places, and people. The subtest is
primarily a measure of their fund of general knowledge. Performance on this subtest also may be
influenced by their cultural experience, as well as their ability to retrieve information from long-
Comprehension
(supplementary
subtest)
The Comprehension subtest required the individual to provide oral solutions to everyday problems
and to explain the underlying reasons for certain social rules or concepts. This subtest provides a
general measure of verbal reasoning and conceptualisation, verbal comprehension and expression.
In particular, this subtest assesses comprehension of social situations and social judgment, as well
as knowledge of conventional standards of social behaviour.
PERCEPTUAL
REASONING
INDEX
The Perceptual Reasoning Index (PRI) is a measure of fluid reasoning, spatial processing,
attentiveness to detail, and visual-motor integration comprising the 3 core Performance subtests of
Visual Puzzles, Block Design, and Matrix Reasoning and two supplemental subtests; Figure
Block Design The Block Design subtest required the individual to use two-colour cubes to construct replicas of
two-dimensional, geometric patterns. This subtest assesses ability to mentally organize visual
information. More specifically, this subtest assesses the ability to analyse part-whole relationships
when information is presented spatially. Performance on this task also may be influenced by visual-
spatial perception and visual perception
fine motor coordination, as well as planning ability.
Matrix Reasoning The Matrix Reasoning subtest involves a series of incomplete gridded patterns that the individual
completes by pointing to or saying the number of the correct response from 5 possible choices. This
subtest assesses fluid intelligence, broad visual intelligence, classification and spatial ability, as well
whole relationships and perceptual organisation abilities.
Visual Puzzles The Visual Puzzles subtest requires the individual to view a completed puzzle and to then select
three response options, which when combined will form the completed puzzle. This is a measure of
an individual’s non-verbal reasoning ability and their ability to both analyse and synthesise abstract
Picture Completion
*
(supplementary
subtest)
The Picture Completion subtest required the individual to identify the important missing part in
each of a series of pictures of common objects, events, or scenes. An indication of their ability in
visual discrimination, the Picture Completion subtest assesses the abilities to detect essential details
in visually presented material and to differentiate them from nonessential details. Performance on
this task also may be influenced by an individual's general level of alertness to the world around
Figure Weights
(supplementary
subtest)
The Figure Weights subtest involves viewing a scale, which is missing weight(s) and then selecting
the response option which balances that scale. This is a measure of quantitative and analogical
reasoning, which involves reasoning processes that can be expressed mathematically. The task
emphasises the use of deductive and inductive logic.