Weschler Tests
WAIS: Adult Intelligence Scale
WISC: Intelligence Scale for Children
WPPSI: Preschool and Primary Scale of
Intelligence
History
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1939:
1950:
1955:
1974:
1981:
1997:
2002:
2003:
Weschler Bellvue
WISC
WAIS
WISC-R
WAIS – R
WAIS-III
WPPSI-III
WISC IV
Rationale for Weschler’s tests
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More appropriate content for adults on
the WAIS
Broader coverage the Stanford Binet
Separate scores for components of
intelligence
Better norms
Stratified Sampling in WAIS
For an test to be used for all adults in the
US, what variables should stratified on
in the sampling?
Variables used to select a
stratified sample in WAIS
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Age: 13 age groups, 16 to 89
Sex: M, F
Race: White, non-white
Geographic region: 4 regions
Occupation: 6 occupational groups
Education
Residence: urban, rural
Example using 1995 Census
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Consideration of a combination of
region, age, and sex
Structure of WAIS
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Scores on 19 scales in several content
areas: Information, Block Design, Word
Reasoning
Scores on traditional theoretical
organization of Verbal IQ, Performance
IQ, and Full Scale IQ
Scores on four Indices resulting from
factor analysis of the 19 content scales
Profile Analysis: pathologies
show more scatter, e.g. schizo
Low
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Middle
Compre
Arith
Similarities
Vocab
Digit
Block
Coding
Objec Assem
Digit Symbol
High
X
X
X
X
X
X
X
X
X
Profile Analysis: Brain damage
Low
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Compre
Arith
Similarities
Vocab
Digit
Block
X
Coding
Objec Assem
Digit Symbol
Middle
High
X
X
X
X
X
X
X
X
Profile Analysis: Psychopathic
character disorder
Low
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Compre
Arith
Similarities
Vocab
Digit
Block
Coding
Objec Assem
Digit Symbol
Middle
High
X
X
X
X
X
X
X
X
X
Group Tests of Cognitive
Abilities
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Can be administered to more than one
person at a time
Historically called “paper and pencil”
tests
Now can be administered electronically
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On computer
On line, web-based systems (ISSUES!!)
Advantages
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Standardization
Examiner has no/small influence
Mass testing
Multiple choice format simplifies scoring
Scoring can be objective
Adaptive testing
Better norms
Disadvantages
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Examiner cannot make observations about
each individual, e.g. is person ill
Restrictions on the response mode: just make
on paper (?)
More difficult to have individuals take
different questions
Difficult to measure certain attributes, e.g.,
sensori-motor functions
Not appropriate for certain individuals, e.g.,
inexperienced with these formats
Scholastic Aptitude Tests
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SAT
ACT
GRE
MCAT
LSAT
Some Paper and Pencil Tests
of “g”
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Hidden Figures Test -Gottschaldt
Figures
Matrices
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Raven Progressive Matrices
Figural Patterns
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Cattell Culture Fair Intelligence Test
Wonderlic Personnel Test
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A measure of general mental ability “g”
Short, timed, 12 minutes
Several forms: 11 languages, Braille, large
50 items
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Spiral omnibus format: gets more difficult,
changing topics
Word comparisons, disarranged sentences,
following directions, number comparisons, number
series, story problems, spatial, logic
Primary Mental Abilities
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Thurstone, 1938
Weschler
7 to 9 cognitive abilities
Resulted from theory and research
finding showing clusters of behaviors
Examples of abilities and test items
Verbal
Vocabulary, synomyms,
comprehension antonyms, reading
Verbal fluency Rapid production of words
Number ability Arith word problems, arith
reasoning, arith computation
Spatial
Mental manipulation of symbols
visualization
and figures
Memory
Recall of words, paired
associates, coding tasks
Reasoning
Analogies, series
Perceptual
speed
Cross out “Ls”
ALMJLBEL
Multiple Aptitude Test
Batteries
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A “battery” is a coordinated set of tests
measuring several attributes
Several test of related abilities developed,
normed, evaluated, and packaged by one
publisher
Examples
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Differential Aptitude Tests (DAT)
General Aptitude Test Battery (GATB)
Armed Services Vocational Aptitude Battery
(ASVAB)
Differential Aptitude Test
(DAT)
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Verbal Reasoning
Numerical Ability
Abstract Reasoning
Space Relations
Mechanical Reasoning
Clerical Speed and Accuracy
Language Usage
Spelling
Psychometric Information on
the DAT
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Norms: national sampling, ½ male and
female, Grades 8 to 12, workers
Reliability
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Validity
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Parallel forms: .68 to .86, percentile bands
Predictive of grades in math, science, social
studies, English; Follow up study
Support material: brochures, profile forms,
career planning using Career Planning Qst
Seven-Year Follow-up Study
with DAT
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1430 senior high school students
examined with DAT, then followed for 7
years to learn what school level and
what occupation
Criterion: Education level
attained 7 years later
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Educ level
Advanced degree
College graduate
Some college
Specialty school
No further school
Criterion:
Education level attained
Educ level
Advanced degree
Average Verbal Average
Reasoning
Numerical
86
84
College graduate
79
79
Some college
61
57
Specialty school
40
31
No further school
34
30
Criterion:
Occupation entered
Job working
in?
Engineers
What test did they get highest
score on? And what was mean
VR = 84, NA = 89
Drafting,
engineer aide
Technicians
SR = 67
Office jobs
Clerical = 64
Sales
AR = 58
MR = 53
Other multiple aptitude
batteries
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General Aptitude Test Battery (GATB)
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Used in US employment offices
Controversy over race norming; CRA of
1991
Armed Forces Vocational Test Battery
(ASVAB)
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Used in military induction centers
Guilford’s
Structure of Intellect Model
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“Search model” – has heuristic value
120 facets of intelligence
5 Operations: kinds of mental processes
4 Contents:what you are thinking about
6 Products: the form in which the
information occurs
Ex: Cognition of semantic…
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Units: vocabulary, synonyms
Classes: verbal classifications
Relations: verbal analogies, order
Systems: arithmetic operations
Transformations: similarities
Implications: “Effects” test
Creativity: Divergent Thinking
about ….
Various Content <--> Various Products
Figures
Units
Symbols
Classes
Word = semantics
Relations
Behaviors
Systems
Transformations
Implications
Other Tests of Specific Abilities
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Emotional Intelligence
Gardner’s Multiple Intelligences
Disabilities and Testing
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Diagnosing disabilities
Accommodating disabled individuals in
testing
Definitions
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Child experiencing delays, or has
condition which will result in delay
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Individuals With Disabilities Act (1997)
Adult with a physical or mental
impairment that limits a major life
activity
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American With Disabilities Act (1990)
Diagnosing disabilities
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Must be done by a qualified examiner
Must be documented in some formal,
proven way
Poor performance is not necessarily the
result of a disability
Assessing various types of
disabilities
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Physical
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Vision: optical expert
Hearing: audiologist
Motor: special ed person, PT, med doc
Mental/cognitive
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Mental retardation: “IQ” tests: WISC
Adaptive behavior: Vineland
Emotional: personality tests, behavioral
observations
Accommodations
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Access
Services
Testing
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Forms, mode of response, environment,
aids, time allowed
Standards for Educ and Psych Tests
Ethical Principles of Psychologists
Two Points of View
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Tests are biased
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Tests are not biased
Psychometric Terms related to
test bias
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Adverse Impact
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Bias in measurement = slope bias
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Mean difference in scores
Disproportionate selection rates
Differential validity: difference in r
Bias in prediction = intercept bias
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Unfair discrimination
Systematic under-prediction of success
“Tests are biased”
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Arguments that cognitive ability tests
are BIASED and should NOT be used to
assess minorities
Tests are biased
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African Americans score 10-15 points lower
than whites; Hispanic/Latinos score 5 – 7
points lower than whites
5 point difference remains after using controls
IQ tests have white, anglo-saxon, middle
class content
Ethnic minorities score lower because of
differences in motivation and exposure to
tests
Tests are biased, continued
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Tests are differentially valid (slope bias)
Tests under-predict success for minorities
(“intercept bias”)
Validation research has used poor criteria
Test results induce negative expectations
IQ is partially environmentally determined
Use alternatives
Heritability
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Heritability is the proportion of total variance
in test scores due to genetic factors: h
squared
Total test variance = variance due to genetics
+ variance due to environment
Estimates of heritability in cognitive ability:
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Some testing texts: 30- 40%
General literature: 50 – 70%
Older ages: 80%
Twins’ studies
Identical twins reared together
Identical twins reared apart
Fraternal twins reared together
Fraternal twins reared apart
Siblings
Natural parent and child
Adoptive parent and child
Correlation of
test scores
.91
.75
.55
.30
.50
.44
.02
Tests are not biased
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Arguments that cognitive ability tests
are NOT biased and should be used to
assess minorities
Tests are not biased
African Americans and Hispanis score lower on
numerous tests of cognitive ability
 Test score differences persist even after
controls for SES and even with the use of
culture free and culture fair cognitive tests
 Culturally different individuals from other
groups do as well as whites
 White examiners do not treat minority
examinees differently
Tests are not biased
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Differential validity (“slope bias”) occurs
no more frequently than chance. Well
developed tests are equally valid
Tests do not under-predict success for
minorities; if any thing they over-predict
success for minorities
Cognitive ability tests predict success in
school, occupations, military, life
Tests are not biased
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Tests provide diagnosis and help
identify special educ and enrichment
Tests serve to evaluate outcomes of
program; part of solution
IQ is partially (largely) genetically
determined
Alternative are more biased; tests are
“color blind”
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Weschler Tests