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46-320-01
Tests and Measurements
Intersession 2006
Defining Intelligence
Psychometric approach
Information-processing approach
Cognitive approach
Spearman
Intelligence consists of one global factor (g)
and specific factors
Positive manifold: all tests are influenced
by g
Factor analysis

Half the variance in diverse mental ability tests
is represented by g
Intelligence best represented by one score
Multiple Intelligences
gf-gc theory
Fluid (gf)
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Reason, think, acquire new knowledge
Crystallized (gc)
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Knowledge and acquired understanding
Binet
Binet: the capacity to:
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Find and maintain a definite direction or purpose
To make necessary adaptations to achieve that purpose
For self-criticism so the adjustments can be made
Age Differentiation

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Capabilities distinguish
2/3 to 3/4 of children of a certain age
Independent of chronological age
General Mental Ability

Total product of all capabilities/elements of intelligence
1905 Binet-Simon Scale
First major intelligence measure
30 increasingly difficult items
Terms: idiot, imbecile, moron
Poor validation sample
1908 Scale
Age scale
One score – verbal, language, and reading
abilities
Mental age – 2/3 to 3/4 of items at age level
1916 Stanford-Binet Intelligence
Scale
Terman
Intelligence Quotient (IQ):
MA
100
IQ 
CA
16 maximum CA
1937 Revision
Revisions in scoring, instructions
Performance items included
Alternate Forms L and M
IQ scores not equivalent across age
1960 Scale
No alternate forms
Deviation IQ
Standard score: mean 100, sd 16
 New tables corrected for variability differences
across ages

1972: new normative sample, included
nonwhites
Modern Stanford-Binet
Incorporated gf-gc theory
Crystallized
abilities
g
Fluid-analytic
abilities
Short-term
Memory
1986: Age scale eliminated – 15 separate
tests

Standard age scores, mean 50, sd 8
1986 Administering the Test
Starting point:

CA used with score on Vocabulary test
Basal Age

Lowest level where 2 consecutive items are
passed
Ceiling

At least 3 of 4 items are missed
Interpreting Results
Four area-content scores
Composite score
Mean 100, sd 16
1986 Psychometric Properties
Reliability
.90 minimum – met by composite and area
scores (both KR20 and test-retest)
 Individual tests – some below this

Validity
Factor analysis: generally supports 4 group
factors and g factor
 Correlates well with other measures

Overall, meets expectations
2003 Fifth Edition
2 routing measures (verbal and nonverbal)
10 subtests total
5 factors:

Fluid Reasoning; Knowledge; Quantitative Reasoning;
Visual/Spatial Reasoning; Working Memory
Return to age scale format
Scaled scores: mean 10, SD 3
Standard Scores (Full-scale IQ, Nonverbal IQ,
Verbal IQ, 5 factors): Mean 100, SD 15
Psychometric Properties for 5th
Edition
Normative sample: matches 2001 census

Included an extra sample for subpopulations
Reliability:
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Full-scale IQ: .98
Nonverbal IQ: .95
Verbal IQ: .96
Five Factors: .90 to .92
Adequate to good reliability coefficients and interscorer
agreement for subtests
Validity: full-scale IQ low to mid .8’s with
Weschler scales
Wechsler
Critiqued Binet’s scale
Point scale

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Credits assigned to each item
Group similar items – scores for each content area
Performance scale
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Nonverbal intelligence
Directly compare verbal and nonverbal ability
Intelligence comprised of many elements, can be
measured by summing these elements
Verbal Subtests
Vocabulary: Define words
Similarities: Relationship between two objects, concepts
Arithmetic: Simple arithmetic operations
Digit Span: Repeat sets of digits forwards/backwards
Information: General factual information
Comprehension: Social knowledge & practical information
Letter-Number Sequencing: Intermixed set of letters and
numbers, repeat numbers then letters in ascending order
Performance Subtests
Picture Completion: Ability to see details
Digit Symbol-Coding: Visuomotor speed and scanning
accuracy
Block Design: Reproduce designs with blocks
Matrix Reasoning: Complete visual patterns
Picture Arrangement: Arrange a set of visual images in
correct story sequence
Symbol Search: Look for a target symbol in a set of
symbols
Object Assembly: Assemble pieces of a puzzle
Scoring
Subtest raw scores converted to scaled
scores (mean = 10, sd = 3)
*Age-adjusted norms

Client’s age
Reference-group norms

Standardization sample, age 20 to 34
Convert subtest sum to deviation IQ (mean
= 100, sd = 15)
Scaled Scores
Score Conversions
WAIS-III Scales
IQ scores:
FSIQ – Full Scale IQ
 VIQ –Verbal IQ
 PIQ – Performance IQ

Index Scores:
VCI – Verbal Comprehension Index
 WM – Working Memory
 POI – Perceptual Organization Index
 PS – Processing Speed

Index Scores
Vocabulary
VCI
Similarities
Picture Completion
POI
Information
Matrix Reasoning
Arithmetic
WM
Digit Span
Letter-Number
Sequencing
Block Design
PS
Digit
SymbolCoding
Symbol
Search
WAIS-III IQ Scores
S.D.
IQ
-4 to -3
40 - 55
-3 to -2
55 - 70
-2 to -1
70 - 85
-1 to 0
85 - 100
% Pop’n 0.13%
2.14%
13.59%
34.13%
S.D.
O to 1
1 to 2
2 to 3
3 to 4
IQ
100 - 115 115 - 130
% Pop’n 34.13%
13.59%
130 - 145 145 - 160
2.14%
0.13%
WAIS-III IQ Scores
.3413
.3413
.1359
.1359
.0215
.0215
.0013
.0013
IQ =
55
70
85
100
115
130
145
WAIS-III IQ Descriptors
< 70
70 to 80
80 to 90
90 to 110
110 to 120
120 to 130
>130
Extremely Low
Borderline
Low Average
Average
High Average
Superior
Very Superior
Interpretation
VIQ-PIQ Split

Possible L.D. (also ACID)
Strengths and Weaknesses
Compare Index scores
 Compare subtest scores with mean score
 Generate hypotheses

Psychometric Properties
Standardization: 13 age groups (16-17 to
85-89)
Reliability:
FSIQ: Test-retest .95; Split-half .98
 VIQ: Test-retest .94; Split-half .97
 PIQ: Test-retest .88; Split-half .94
 Not as good for individual subtests

SEM: FSIQ 2.29; VIQ 2.50; PIQ 3.75
WAIS-III Validity
With WISC-III
FSIQ: .93
 VIQ: .94
 PIQ: .86
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High correlations with WAIS-R
WISC-IV
10 core and five supplemental subtests
Grouped into four indices:
Verbal Comprehension
 Perceptual Reasoning
 Working Memory
 Processing Speed
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No VIQ-PIQ