Psychometrics

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Psychometrics

• Dr Jacqui McKechnie

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Psychometric Tests
General Tests WAIS and WISC Specific Tests BDI
and BAI Personality Tests MMPI-II Projective
Tests Rorschach inkblot test
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Theories of Intelligence
Spearman (1904) Two-Factor Theory of
Intelligence. 1) a general factor - g factor 2)
specific factors
Guildford (1967) 120 different factors
Thurstone (1938) 7 primary mental abilities
Goleman (1995) Emotional Intelligence
Gardner (1983) Multiple intelligence - 6 types
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Crystallised Intelligence
specific knowledge e.g. vocabulary increases
with age depends on level of education
influenced by environmental factors
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Fluid Intelligence
basic powers of reasoning and problem
solving Cattells IQ test
starts to decline at 21 years
falls steeply after 60 years
influenced by genetic factors
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Intelligence Tests
Binet Simon (1905) - developed tests for
children based on concept of mental age. IQ
not fixed would help to direct education
should not be used as a label
Stanford - Binet Scale adapted for American
children by Terman Yerkes.
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It was used for classification
IQ score - fixed could rank order
individuals differences attributed to innate
genetics
Intelligence Quotient
mental age
x 100
chronological age
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Adults
standardised to make the average result 100 This
makes the average IQ 100. 95 score
68 - 132
68 score
84 - 116
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Types of IQ test
British Ability Scales developed in
1970s Individual tests- WAIS - Weschler
Adult Intelligence Scale WISC - Weschler
Intelligence Scale for Children Verbal -
vocabulary, arithmetic, reasoning Performance -
picture completion, block design
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Group- AH test - Alice Heim Group comparison,
economical

• Sample Questions
• Give the next but one member of the series
• 1/2, 3/5, 5/8, 7/11
  
• Here are words denoting five generations in one
  family. Which has two, and only two, younger
  relations
• grandmother, great-grandson, son, father,
  grandson
• Here is to there as these is to
• yonder, that, others, those, this

11/17
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Reliability and Validity
Selection There may be biases inherent in the
items chosen. Reliability It is important that
if the same people are tested they give the same
results. Test-retest method Split-half
reliability Alternate-forms reliability
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Validity
Do tests measure what they claim to measure?
Does the test result predict performance? Pred
ictive validity Face validity Content
validity Concurrent validity Construct
validity Consensual validity
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Response Bias
How do we make sure that the test isnt producing
a tendency to answer the questions in one way
rather than another? Questions themselves
could be producing the answers. The way a
question is phrased can also produce a
response. People try to present themselves in
the best light possible. Are tests biased
towards certain cultures? Social desirability
response set Acquiescence response set
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Reliability
3 - 5yrs
r 0.5
r 0.9
12 - 14yrs
r 0.7
66yrs
Validity
IQ academic achievement
r 0.4 - 0.7
IQ occupational status
r 0.5 - 0.6
r 0.3
IQ income
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Inheritance of Intelligence
Burt (1955) 80 hereditary 20 environmental
Kamin (1984) 0 hereditary 100 environmental
Identical twins r 0.87 Fraternal twins
r 0.53 Separated identical twins r
0.66 - 0.77 Siblings r 0.5 Foster children
reared together r 0.2
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Intelligence and Race
IQ scores between black and white Americans have
shown differences of 15 points. Jensen (1969)
stressed biological differences Environmentalists
tests were culturally biased environment
may be different black people may experience
prejudice and discrimination
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Scarr and Weinberg (1976) adoption study - black
children had IQ 25 points higher.
Tyler (1965) IQ differences between black
Americans in north and south.
Educational differences account for up to 24
points in IQ tests
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Yerkes (1921)
Administered IQ tests to 125,000 young men in US
army. Goddard (1913) Administered IQ test to
immigrants to USA.
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Items Relate to the Culture of the Edwards River
Community
many
1. What comes next in the sequence one, two,
three, ___________ ? 2. As wallaby is to animal,
so cigarette is to ________________ ? (Choose
from leaf, tree, tobacco, habit, lung cancer) 3.
One of the following items may not be classified
with salt water crocodile. Which one? (marine
turtle, frilled lizard, budgerigar, black
snake) 4. Which items may be classified with
sugar? (honey, witchetty grub, flour,
water-lilies) 5. We eat food and __________
water. Supply the missing verb.
tree
black snake
all of them
eat