The Wechsler Adult Intelligence Scale (WAIS)

The
Wechsler Adult
Intelligence Scale (WAIS)
Ms. Hemangi Narvekar
Clinical Psychologist

CONTENTS
 Introduction
 David Wechsler
 Antecedents & Evolution
 Description of WAIS
 Revisions
 Strengths
 Limitations
 Applications
 Conclusion
 References

INTRODUCTION
 Individual intelligence testing is one of the major
achievements of psychology since the founding of the
discipline.
 Since Alfred Binet first used a standardized test to
identify learning-impaired children in the early 1900s,
it has become one of the primary tools for identifying
children with mental retardation and learning disabilities.
 Researchers have developed new, more sophisticated
ways of creating, administering and interpreting tests.
And they have produced new theories and tests that broaden the concept of
intelligence beyond its traditional boundaries.

DAVID WECHSLER
(1896-1981)
 David Wechsler, who pioneered the field of cognitive
psychology, was one of the most renowned psychologists
of the 20th century.
 In 1932, Wechsler began his long career as chief
psychologist at the Bellevue Psychiatric Hospital in New
York.
 Although Wechsler engaged in a variety of research
projects, his major focus continued to be intelligence.
 Wechsler described intelligence as “the global capacity of
a person to act purposefully, to think rationally, and to
deal effectively with his environment (Wechsler, 1944).”

DAVID WECHSLER
(1896-1981)
 In 1939, Wechsler published The Measurement of Adult
Intelligence.
 Wechsler developed
- the Wechsler-Bellevue Intelligence Scale
- the WISC (Wechsler Intelligence Scale for Children)
- the WAIS (Wechsler Adult Intelligence Scale)
- the WMS (Wechsler Memory Scale) and
- the WPPSI (Wechsler Preschool and Primary Scale of
Intelligence)

Antecedents & Evolution of
the Wechsler Intelligence Scales
 The first form of the Wechsler Scales, known as the Wechsler-Bellevue
Intelligence Scale, was published in 1939.
 Primary objective → to provide an intelligence test suitable for adults
 Wechsler (1939) pointed out that previously available intelligence tests
had been designed primarily for school children and had been adapted
for adult use by adding more difficult items of the same kinds.
 The content of such tests was often of little interest to adults.
 He likewise called attention to the inapplicability of mental age norms to
adults and pointed out that few adults had previously been included in
the standardization samples for individual intelligence tests.

The Bellevue scale consists of 11 subtests, 6 being
verbal in content and 5 nonverbal.
Verbal Scales
Information
General comprehension
Arithmetical reasoning
Memory span for digits
Similarities
Vocabulary
Performance Scales
Picture arrangement
Picture completion
Block design
Object assembly
Digit-symbol test

The Wechsler Adult Intelligence Scale
(WAIS)
 The original WAIS (Form I) was published in February 1955 by David
Wechsler, as a revision of the Wechsler-Bellevue Intelligence Scale.
 Age group: 16 years and over
 The theoretical basis for the WAIS came from Wechsler's belief that
intelligence is a complex ability involving a variety of skills.
 All of the WAIS tests are based on
hierarchical models of intelligence such as
Spearman’s g (Spearman, 1923), & the two-factor
theory of Cattell (1963), which distinguishes
between fluid and crystallized intelligence.
 Like Bellevue scale, WAIS also consists of
11 subtests, 6 being verbal in content and 5 nonverbal.

VERBAL SCALES
INFORMATION
• 29 questions covering variety of
information
• E.g. How many weeks are there in
a year?
ARITHMETICAL
REASONING
• 14 mental arithmetic brief story
type problems
• E.g. How many inches are there in
4 feet?
• It tests distractibility as well as
numerical reasoning
VOCABULARY
• Defining 40 words
• E.g. What is a guitar?
• It measures expressive word
knowledge

VERBAL SCALES
COMPREHENSION
• 16 open ended questions
• E.g. Why should people pay
taxes?
• It measures practical judgement,
common sense, and the ability to
understand and adapt to social
customs
DIGIT SPAN
• List of 2 to 9 digits
• It measures short-term memory,
attention, and concentration
SIMILARITIES
• 12 sets of paired words
• E.g. In what way are an apple and
a pear alike?
• It measures concrete, functional,
and abstract concept formation

PERFORMANCE SCALES
PICTURE COMPLETION
• 20 small pictures that all have one
vital detail missing
• E.g. a picture of a face with the
nose missing
• It measures ability to observe
details and recognize specific
features of the environment
PICTURE
ARRANGEMENT
• 10 sets of small pictures
• It measures nonverbal reasoning
and sequencing skills, and grasp of
social cause and effect
BLOCK DESIGN
• 9 red and white square blocks and
a spiral booklet of 10 cards
• It measures spatial problem-
solving and manipulative abilities,
and part to whole organization

PERFORMANCE SCALES
DIGIT SYMBOL
• Numbers 1 - 7 are paired with
symbols
• It measures visual-motor speed and
complexity, motor coordination
OBJECT ASSEMBLY
• Flat cardboard that have been cut up
to form a jig-saw puzzle
• It measures visual-motor problem-
solving and organizational abilities,
and visual anticipation skills

 Administration
 WAIS administrators must receive proper training and be aware of all test
guidelines.
 Testing requires approximately 90 minutes.
 Scoring & Interpretation
 All tests of WAIS are scored on a point basis
 Raw scores on each test are converted to standard scores with a mean of
10 and a standard deviation of 3.
 Scores in the Verbal battery are summed and converted to a Verbal IQ
score; the same is done for the Performance scale scores which yield the
Performance IQ score.
 The Verbal and Performance IQ scores are summed and converted to
obtain the Full Scale (overall) IQ score.
 The appropriate verbal, performance and full scale IQ score are then added
and converted to standard scores, with mean of 100 and standard deviation
of 15, which are designated as “Deviation IQs”.

 Standardization
 Norms are based upon a sample of 1700 persons from 4 widely
separated geographic areas of age range 16 to 64 years.
 Supplementary data were also obtained for a sample of older
persons (N=352) above 65 years of age.
 Reliability
 Internal consistency and test retest reliabilities are about .95 or
higher for full scale and verbal scores.
 Generally, performance reliabilities are low than verbal reliabilities
on the subtests.

REVISIONS
1981 • WAIS-R
1997 • WAIS-III
2008 • WAIS-IV

WAIS-R
 The WAIS-R was released in 1981
 Age group - 16 and up
 It consists same verbal and Performance scales
 Administration
 It takes around 60-90 minutes to complete the full scale.
 The verbal & performance scales can be used alone.
 There is little emphasis on speed in this test with only some
subscales having time limits and some subscales having bonuses
for speed.
 The scoring is done in the same manner like the scoring of WAIS.

WAIS-R
 Standardization
 The WAIS(R) was standardised on a sample of 1,800 U.S. subjects,
ranging from 16 to 74 years of age.
 Equal numbers of men and women were used, as were white and non-
white subjects, in line with census figures.
 There are different adaptations of the scale by country. For example, in
Australia we have the Australian adaptation of the WAIS-R (1989).

WAIS-R
 Reliability
 Internal consistency:
.93 for the Performance IQ
.97 for the Verbal IQ
.97 for the full scale
 Split half reliability is more than .95 (very strong)
 Reliability for the 11 subtests is not as strong
 Validity
 Evidence supports the validity of WAIS-R as a measure of global
intelligence.
 It is correlated highly with other IQ tests (e.g. The Stanford-Binet)
 It is significantly correlated with a number of criteria of academic and
life success, including college grades, measures of work
performance and occupational level.

WAIS-III
 The WAIS-III was released in 1997
 Age Group - 16 and 89 years
 It provided scores for Verbal IQ, Performance IQ, and Full Scale IQ,
along with four secondary indices.
 Indices:
• The Verbal Comprehension Index (VCI)
• The Working Memory Index (WMI)
• The Perceptual Organization Index (POI)
• The Processing Speed Index (PSI)

 WAIS-III also contains two scales – Verbal and Performance Scale
 Verbal scales included 7 tests and provided two sub indexes - verbal
comprehension and working memory
VERBAL COMPREHENSION
INDEX (VCI)
Information
28
Questions
Similarities
19 items
Vocabulary
66 words
THE WORKING MEMORY
INDEX (WMI)
Arithmetic
19 Problems
Digit Span
19 items

 The last two verbal tests i.e. Letter-number sequencing (new) and
Comprehension are not included in these indices.
Letter-number
sequencing
Ordering numbers
and letters presented
in an unordered
sequence
Comprehension
It requires examinee
to solve practical
problems and
explain the meaning
of proverbs

 Performance scale included six tests and it also provided two sub
indexes - perceptual organization and processing speed
E.g. E.g.
THE PERCEPTUAL
ORGANIZATION INDEX (POI)
Block
Design
Picture
Completion
Matrix
Reasoning
(NEW)
It measures
nonverbal
analytical
reasoning
THE PROCESSING SPEED
INDEX (PSI)
Digit-Symbol
Coding
Symbol Search
(NEW)
It measures
organization
accuracy and
processing speed

 The last performance test i.e. Picture Arrangement and Object
Assembly is not included in these indices. Object Assembly is not
included in the Performance scale.
Picture
Arrangement
Arranging
pictures in order
to tell a story
Object
Assembly
Assemble
pieces in such a
way that a whole
object is built

 Administration
 The WAIS-III takes about 60–75 minutes to complete
 There is some flexibility in the administration of the WAIS—the
administrator may end some subtests early if test takers seem to
reach the limit of their capacity.
 The scoring is done in the same manner like the scoring of WAIS
 We get three composite scores: verbal, performance, full scale,
each with mean=100 & SD=15 and four index scores: verbal
comprehension, perceptual organization, working memory,
processing speed.

 Standardization
 WAIS-III was standardized on a stratified sample of 2,450 adult
representative of the U.S. population aged 16-89 (Tulsky et al.,
1997; Wechsler, Coalson, & Engi Raiford, 2008).
 There were 200 cases per age group, except for the smaller
numbers in the two oldest groups.
 To assess cultural bias, WAIS III items were given to 200 African-
American and Hispanic-American clients without discontinue rules;
items which minorities seldom answered correctly were thrown out.
 The revised version has almost 80 per cent of the original form.

 Reliability
IQ/Index Test-Retest
Reliability
SEM
Full Scale .96 2.3
Verbal IQ .96 2.5
Performance IQ .91 3.7
Verbal
Comprehension
.95 3.0
Perceptual
Organization
.88 4.0
Working Memory .89 3.8
Processing Speed .89 5.1
 Validity
 Content validity was established by
expert judges who reviewed the items.
Criterion validity was established by
correlating WAIS-R and WAIS III. The
numbers are good, and Full Scale IQ
is about three points higher on the
WAIS-R.
 Construct validity come from
correlating the WAIS III with other
intelligence tests. The WAIS III
Performance IQ and Perceptual
Organization Index correlated with the
Ravens Matrices .79 and .65
respectively.

WAIS-IV
 The current version of the test, the WAIS-IV, was released in 2008
 Age Group - 16–90 years
 Goals –
1. Updating theoretical foundations
2. Increasing developmental appropriateness
3. Increasing user-friendliness
4. Enhancing clinical utility
5. Improving psychometric features

 WAIS-IV is composed of 10 core subtests and 5 supplemental
subtests, with the 10 core subtests comprising the Full Scale IQ.
 Some of the changes were:
 The verbal/performance subscales from previous versions were
removed and replaced by the index scores.
 4 subtests were dropped which were Object Assembly, Picture
Arrangement, Coding Recall (Digit Symbol-Incidental Learning), and
Coding Copy (Digit Symbol-Copy)
 12 subtests were retained which are Similarities, Vocabulary,
Information, Comprehension, Block Design, Matrix Reasoning,
Picture Completion, Digit Span, Arithmetic, Letter-Number
Sequencing Symbol Search, and Coding
 3 new tests i.e. Visual Puzzles, figure Weights, and Cancellation
were included

The Verbal Comprehension Index (VCI)
• 12 of 18 items are
new
Similarities
• 3 new picture
items
• 6 new verbal
items
• New scoring
Vocabulary
• 11of 26 items are
new
• Scoring criteria
was changed
Information
• Supplemental
Comprehension

The Perceptual Reasoning Index (PRI)
new
• Instructions were
shortened
• Bonus points were
eliminated
Block Design
• Item types reduced
to 2 from 4
new
Matrix
Reasoning
• Supplemental
Picture
Completion

The Perceptual Reasoning Index (PRI)
• New
• It measures non-
verbal reasoning
Visual
Puzzles
• New
• 16-69 0nly
• It reveals quantitative
and analogical
reasoning
• Supplemental
Figure
Weights

The Working Memory Index (WMI)
• 5 trials of digit span
forward and 9 trials of
digit span backward are
new
• 2 new sample items
Digit span
• 11 of 12 retained items
were revised
• 9 new items were added
• Presentation blocks were
eliminated
• Picture items were
added
Arithmetic
• 16-69 0nly
• Supplemental
Letter-Number
Sequencing

The Processing Speed Index (PSI)
• Examinee now has to
mark the symbol or the
NO box
• Instructions were
simpliﬁed
• Symbols were enlarged
Symbol
Search
• 2 symbols were retained but
revised
• 4 new symbols were added
• Samples were increased
from 4 to 6
• Total items were increased
• 16-69 0nly
• Supplemental
Coding
• New
• 16-69 0nly
• It reveals visual-perceptual
speed
• Supplemental
Cancellation

 Standardization
 The standardization sample (N = 2,200) was obtained using stratified
proportional sampling across variables of age, sex, race/ethnicity, education
level and geographic region.
 An extension of the standardization has been conducted with 688
Canadians in the same age range.
 Reliability
 Internal consistency was found to be:
.97-.98 for the FSIQ
.87-.98 for the factor index scores (VCI, PRI, WMI, PSI)
.71-.96 for the subtests (Hanna, Bradley, & Holen, 1981)
 Short-term test-retest stability was investigated for 298 individuals from
four age groups with retest intervals ranging from 8-82 days. Stability
coefficients were highest for the FSIQ and VCI followed by the PRI, WMI,
and PSI scores, and generally lower for the subtests as found in other
intelligence tests.
 Inter-scorer agreement: .98–.99. for Subtests

 Validity
 High correlations were obtained across academic areas with WAIS-IV FSIQ
correlations with WIAT-II composites ranging .65–.88 and ranging .42–.80
for WIAT-II subtests.
 Relationships between the WAIS-IV and the recently published WIAT-III
(Wechsler, 2009) with a small sample (N = 59) were similar with WAIS-IV
FSIQ correlations with WIAT-III composites ranging .59–.82 and ranging
.33–.81 for WIAT-III subtests. Thus, typically strong concurrent relationships
with academic achievement measures were observed.
 Correlations between scores were in the .80 range with tests that
measure similar constructs, providing convergent validity evidence.
 In contrast, WAIS-IV scores were negatively correlated with the Brown ADD
scales, providing discriminant validity evidence.

 Administration
 Require 2 hours or less to complete
 The WAIS-IV uses 10 core subtests to produce the FSIQ.
 The General Ability Index (GAI) is calculated from the 3 verbal
comprehension and 3 perceptual reasoning subtests.

The Wechsler Adult Intelligence Scale® –
Fourth Edition
 The Wechsler Adult Intelligence Scale® Edition is adapted and
standardized for India.
 WAIS-IVINDIA was published in 2013
 Age Group-16 to 84 and 11 months
 WAIS-IVINDIA is the updated version of (WAIS-III)
 It takes around 75 minutes for administration

 Its key features include –
• Culturally appropriate test items
• Added teaching items to ensure understanding of task
• Reduced vocabulary-level for verbatim instructions
• Enlarged visual stimuli
• Indian norms with enhanced clinical utility
• Norms available for older adults
• Improved floors and ceilings
• Expanded FSIQ range
• Improved subtest and composite reliability
• Reduced item bias
• Reduced testing time
• Revised instructions for clarity and consistency
• Increased portability

STRENGTHS
 WAIS IV provides a strong theoretical framework for the
development and interpretation of test scores.
 The 15 subtests provide a comprehensive assessment of basic
cognitive skills, especially abilities related to verbal, perceptual,
and working memory processing.
 The test authors provide extensive norming, validation, and
standardization data that facilitate inferences drawn about
examinees.
 The test includes excellent support documentation such as the
technical manual and the administration and scoring manual.
 The WAIS is considered to be a valid and reliable measure of
general intelligence.
 The WAIS has also been found to be a good measure of both fluid
and crystallized intelligence.

LIMITATIONS
 The test is time and labour intensive to administer, score, and
interpret; thus, it may be most appropriate when high-stakes
decisions are made.
 The test assesses what some critics have referred to as “left-brain”
or “academic” intelligences, which focus on traditional cognitive
abilities an examinee would use in typical school or work settings.
 Also some experts have argued that social, kinaesthetic,
interpersonal, and emotional intelligence are not assessed at all by
the WAIS (Gardner, 1999).

APPLICATIONS
 As a psycho educational tool to obtain a comprehensive assessment
of general cognitive functioning
 To provide reliable and valid data in academic and educational
settings
 To identify cognitive strengths and weaknesses in a variety of
neurological conditions
 As part of an assessment battery to identify learning difficulties and
giftedness
 To provide valuable information for clinical and neuropsychological
evaluation
 To guide treatment planning and placement decisions
 To provide reliable and valid data for research purpose

SUMMARY
 The WAIS and its revisions are intended to measure human
intelligence reflected in both verbal and performance abilities.
 Wechsler published the first version of the WAIS in 1939, initially
called the Wechsler-Bellevue.
 The newest version is the WAIS-IV (most recently updated in 2008).
 The WAIS is today the most commonly administered psychological
test (Kaplan & Sacuzzo, 2009).
 The tests are currently updated approximately every ten years to
compensate for the Flynn effect.

CITATIONS
• Ackerman, P. L., & Lohman, D. F. (2006). Individual differences in cognitive functions. In P. A.
Alexander & P. H. Winne (Eds.), Handbook of educational psychology (pp. 139-161). Mahwah, NJ:
Lawrence Erlbaum.
• Carroll, J. B. (1993). Human cognitive abilities: A survey of factor-analytic studies. Cambridge,
England: Cambridge University Press.
• Cattell, R. B. (1963). Theory of fluid and crystallized ability: A critical experiment. Journal of
Educational Psychology, 54, 1-22.
• Ericsson, K. A. (2003). The acquisition of expert performance as problem solving: Construction and
modification of mediating mechanisms through deliberate practice. In J. E. Davidson & R. J. Sternberg
(Eds.), The psychology of problem solving (pp. 31-83). Cambridge, England: Cambridge University
Press.
• Gardner, H. (1999). Who owns intelligence? The Atlantic Monthly, 283, 67-76.
• Kaplan, Robert M.; Saccuzzo, Dennis P. (2009). Psychological Testing: Principles, Applications, and
Issues (7th ed.). Belmont (CA): Wadsworth.
• Pyryt, M. (1996). IQ: easy to bash, hard to replace. Roeper Review, 18(4), 255–258.
• Sattler, J. M. (2001). Assessment of Children Cognitive Applications (4th ed.). San Antonio: Sattler.
• Spearman, C. (1923). The nature of “intelligence” and the principles of cognition. Oxford, England:
Macmillan.
• Wechsler, David (1939). The measurement of adult intelligence. Baltimore: Williams & Wilkins, p. 229.
• Wechsler, D. (2002). Wechsler Individual Achievement Test-Second Edition. San Antonio, TX: The
Psychological Corporation.
• Wechsler, D. (2009). Wechsler Individual Achievement Test-Third Edition. San Antonio, TX: Pearson.
• Winner, E. (2000). The origins and ends of giftedness. American Psychologist, 55, 159-169.

REFERENCES
Book References –
 Anastasi, A.,& Urbina, S. (2008). Psychological Testing (7th ed.).Delhi: Pearson
Education.
 Cohen, R.J., & Swerdlik, M.E. (2010). Psychological Testing and Assessment:
An Introduction to Tests & Measurement (7th ed.). New Delhi: McGraw Hill
Education Private Limited.
 Freeman, F.S. (1976). Theory and Practice of Psychological Testing (3rd ed.).
New Delhi: Oxford & IBH Publishing Company.
 Gregory, R.J. (2014). Psychological Testing: History, Principles and
Applications (6th ed.). Noida: Dorling Kindersley Private Limited.
 Kaplan, R.M., & Saccuzzo, D.P. (2007). Psychological Testing: Principles,
Applications, and Issues (5th ed.). Australia- Thomson Wadsworth.
 Murphy, K.R.,& Davidshofer, C.O. (1998). Psychological Testing: Principles &
Applications (4th ed.). New Jersey: Prentice Hall.

Website References –
 http://jpa.sagepub.com/content/2/2/125.abstract
 http://www.sciencedirect.com/science/article/pii/S0887617700000482
 http://www.pearsonclinical.com/authors/wechsler-david.html
 http://psychology.jrank.org/pages/650/David-Wechsler.html
 http://www.nytimes.com/1981/05/03/obituaries/dr-david-wechsler-85-author-
of-intelligence-tests.html
 http://www.iupui.edu/~flip/wechsler.html
 http://www.psychpage.com/learning/library/intell/wais_history.html
 http://www.minddisorders.com/Py-Z/Wechsler-adult-intelligence-scale.html
 http://sevencounties.org/poc/view_doc.php?type=doc&id=8219&cn=18
 http://psychology.about.com/od/intelligence/a/wechsler-adult-intelligence-
scale.html
 http://www.education.com/reference/article/weschler-intelligence-test/

The Wechsler Adult Intelligence Scale (WAIS)

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to The Wechsler Adult Intelligence Scale (WAIS)

Similar to The Wechsler Adult Intelligence Scale (WAIS) (20)

More from Hemangi Narvekar

More from Hemangi Narvekar (16)

Recently uploaded

Recently uploaded (20)

The Wechsler Adult Intelligence Scale (WAIS)