Weschler Tests
WAIS: Adult Intelligence Scale
WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of
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(2)History
1939: Weschler Bellvue
1950: WISC
1955: WAIS
1974: WISC-R
1981: WAIS – R
1997: WAIS-III
Rationale for Weschler’s
tests
More appropriate content for
adults on the WAIS
Broader coverage the Stanford
Binet
Separate scores for components of
intelligence
Stratified Sampling in
WAIS
Variables used to select a
stratified sample in WAIS
Age: 13 age groups, 16 to 89
Sex: M, F
Race: White, non-white
Geographic region: 4 regions
Occupation: 6 occupational groups
Education
Example using 1995
Census
Consideration of a combination of
Structure of WAIS
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
Profile Analysis:
pathologies show more
scatter, e.g. schizo
Low Middle High
Compre X
Arith X
Similarities X
Vocab X
Digit X
Block X
Coding X
Profile Analysis: Brain
damage
Low Middle High
Compre X
Arith X
Similarities X
Vocab X
Digit X
Block X
Coding X
Objec Assem X
Profile Analysis:
Psychopathic character
disorder
Low Middle High
Compre X
Arith X
Similarities X
Vocab X
Digit X
Block X
Coding X
Group Tests of Cognitive
Abilities
Can be administered to more than
one person at a time
Historically called “paper and pencil”
tests
Now can be administered
electronically
On computer
Advantages
Standardization
Examiner has no/small influence
Mass testing
Multiple choice format simplifies scoring
Scoring can be objective
Adaptive testing
Disadvantages
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,
Scholastic Aptitude Tests
SAT
ACT
GRE
MCAT
Some Paper and Pencil
Tests of “g”
Hidden Figures Test -Gottschaldt
Figures
Matrices
Raven Progressive Matrices
Figural Patterns
Wonderlic Personnel Test
A measure of general mental ability “g”
Short, timed, 12 minutes
Several forms: 11 languages, Braille, large
50 items
Spiral omnibus format: gets more difficult,
changing topics
Word comparisons, disarranged sentences,
Primary Mental Abilities
Thurstone, 1938
Weschler
7 to 9 cognitive abilities
Resulted from theory and research
finding showing clusters of
behaviors
Verbal comprehensi on Vocabulary, synomyms, antonyms, reading Verbal
fluency Rapid production of words Number
ability Arith word problems, arith reasoning, arith computation
Spatial
visualization Mental manipulation of symbols and figures Memory Recall of words, paired
Multiple Aptitude Test
Batteries
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
Differential Aptitude Tests (DAT)
General Aptitude Test Battery (GATB)
Armed Services Vocational Aptitude Battery
Differential Aptitude Test
(DAT)
Verbal Reasoning
Numerical Ability
Abstract Reasoning
Space Relations
Mechanical Reasoning
Clerical Speed and Accuracy
Psychometric Information
on the DAT
Norms: national sampling, ½ male and
female, Grades 8 to 12, workers
Reliability
Parallel forms: .68 to .86, percentile bands
Validity
Predictive of grades in math, science, social
studies, English; Follow up study
Support material: brochures, profile
Seven-Year Follow-up
Study with DAT
1430 senior high school students
examined with DAT, then followed
for 7 years to learn what school
Criterion: Education level
attained 7 years later
Educ level
Advanced degree
College graduate
Some college
Specialty school
Criterion:
Education level attained
Educ level Average Verbal
Reasoning
Average Numeric al
Advanced
degree 86 84
College graduate 79 79
Some college 61 57
Criterion:
Occupation entered
Job working
in? What test did they get highest score on? And what was mean
Engineers VR = 84, NA = 89 Drafting,
engineer aide
SR = 67
Technicians MR = 53
Other multiple aptitude
batteries
General Aptitude Test Battery
(GATB)
Used in US employment offices
Controversy over race norming; CRA
of 1991
Armed Forces Vocational Test
Guilford’s
Structure of Intellect
Model
“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
Ex: Cognition of
semantic…
Units: vocabulary, synonyms
Classes: verbal classifications
Relations: verbal analogies, order
Systems: arithmetic operations
Transformations: similarities
Creativity: Divergent
Thinking about ….
Various Content
<--> Various Products
Figures Units
Symbols Classes
Word = semantics Relations
Behaviors Systems
Other Tests of Specific
Abilities
Emotional Intelligence
Disabilities and Testing
Diagnosing disabilities
Accommodating disabled
Definitions
Child experiencing delays, or has
condition which will result in delay
Individuals With Disabilities Act
(1997)
Adult with a physical or mental
Diagnosing disabilities
Must be done by a qualified
examiner
Must be documented in some
formal, proven way
Poor performance is not
Assessing various types of
disabilities
Physical
Vision: optical expert Hearing: audiologist
Motor: special ed person, PT, med doc
Mental/cognitive
Mental retardation: “IQ” tests: WISC Adaptive behavior: Vineland
Accommodations
Access
Services
Testing
Forms, mode of response,
environment, aids, time allowed
Standards for Educ and Psych Tests
Two Points of View
Tests are biased
Psychometric Terms
related to test bias
Adverse Impact
Mean difference in scores
Disproportionate selection rates
Bias in measurement = slope bias
Differential validity: difference in r
Bias in prediction = intercept bias
Unfair discrimination
“Tests are biased”
Arguments that cognitive ability
Tests are biased
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
Tests are biased,
continued
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
Heritability
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:
Some testing texts: 30- 40%
General literature: 50 – 70%
Twins’ studies
Correlation of test
scores Identical twins reared
together .91
Identical twins reared apart .75 Fraternal twins reared
together .55
Fraternal twins reared apart .30
Tests are not biased
Arguments that cognitive ability
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
Tests are not biased
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
Tests are not biased
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
