WECHSLER INTELLIGENCE
SCALE FOR CHILDREN - 4TH EDITION
WISC-IV
It
is an individually administered clinical instrument for assessing the
cognitive ability of children
aged 6 years through 16 years 11 months.
WISC
IV has 4 composite scores (instead
of the 2 we had with the WISC III). Full
Scale IQ (FSIQ) is comprises of the four composite scores.
Verbal Comprehension Index (VCI)
Perceptual Reasoning
Index (PRI)
Working Memory Index (WMI)
Processing Speed Index (PSI)
lThe diagram is
from
Radford University, Department
of Psychology, WISC-IV presentation
List
of the Subtest under each of the four Indexes:
(key= "( )" indicated that the subtest is not included in
the index total score.)
Verbal Comprehension Index (VCI): Requires
verbal conceptualization, stored knowledge access and oral
expression. Orally presented questions that assess common-sense
reasoning,
reasoning out or retrieving word associations, and the ability to
describe the nature or meaning of words. Knowledge acquired from
one's environment. Verbal expression
required
(length of response varies). One of the best predictors of
overall
intelligence.
–
lSimilarities
lVocabulary
lComprehensionl
(Information)
l(Word Reasoning)
lPerceptual
Reasoning Index (PRI): Requires
visual perception, organization and reasoning with visually
presented, nonverbal material to solve the kinds of problems that are
NOT school taught.
The
Block design also requires spatial processing, visual-motor
coordination and the ability to apply all skills in a quick, efficient
manner. The highest scores reflect both accurate and very quick
responses.
Picture Concepts score may differ from these other subtest because of
the effect of language on the performance.
lBlock Design
lPicture Concepts
lMatrix Reasoning
l(Picture Completion)
lWorking
Memory Index (WMI): Requires
working memory processes applied to the manipulation of orally
presented verbal sequences. THe ability to temporarily retain
information in memory, by performing some operation or manipulation
with it, and produce a result. Involves attention, concentration,
mental control, reasoning. Essential component of other cognitive
higher order progresses. Closely related to
achievement and learning (LD
students frequently
affected).
lDigit Span
lLetter-Number Sequencing
l(Arithmetic)
lProcessing
Speed Index (PSI):Requires
visual perception and organization, visual scanning, and the efficient
production of multiple motor responses. These
tasks require executive control of attention and sustained effort for a
2-minute period of time while working with simple visual material as
quickly
as possible. Performance on Coding is also dependent on
paired-associative learning.
lCoding
lSymbol Search
l(Cancellation)
The
WISC-IV has a total of 15 subtests, 10
are retained from the WISC-III These
are the five
new subtests:
Word
Reasoning
Matrix
Reasoning
Letter-Name
Sequencing
Symbol Search
Cancellation
Object
Assembly subtest from the WISC III is gone. On
the WISC III there was Picture Arrangement, now
on the WISC IV there is Picture Concepts, under Perceptual Reasoning
Index. (Not
sure if it is testing the same type of information or not. Not
to be confused with the Picture Completion is on both versions of
the WISC).
I
know that parents of child with NVLD were concerned about the loosing
these
two subtests: Object
Assembly and the Picture arrangement.
Schwab
Learning website, parent to parent section:
Current
reports
show that most students
re-tested with the WISC-IV will have approximately a 5 point
discrepancy,
lower (to the negative) because of this newer version of WISC, its
novelty and its
increased difficulty.
The
good news is that the WISC IV has
been normed on normal
peers and for special education populations:
Mental Retardation (MR),
Attention-Deficit / Hyperactivity Disorder (AD/HD), Learning
Disabilities (LD), both AD/HD and LD, Traumatic Brain Injury
(TBI), etc.
With
4 composite scores (vs. 2 as
is the case with the WISC III), there is no standard discrepancy
formula, it now all has to be evaluated in terms of the child's
ability, test results, current educational functioning, achievement
test expectations based on ability, evaluation of the subtests as well
as evaluation of the composite sets.
Some
evaluators have suggested that a 19 point discrepancy in the VCI/PRI
composites may warrant further investigation.
Standard deviation is 15 points, it is not clear that these score
will tell enough about the child's areas of weakness.
The
information
on this was adapted from WISC IV presentations attended, parent
discussions and emails.
WISC-IV by Wechsler, D. (2003),
The Psychological Corporation, and
Dr. Donna R. Smith Power Point presentation, of the Harcourt
Assessment, Inc. Publisher.
For more information please visit these other websites:
