• First edition was first published intelligence test to provide organised and detailed administration and scoring instructions.
  • First American test to employ concept of IQ
  • First test to introduce concept of alternative item: an item to be substituted for a regular item under specified conditions (such as the situation in which the examiner field to properly administer the regular item)
  • Lack of representation of minority groups during test’s development
  • 1960 – SB-3 —> deviation IQ introduced (instead of ratio IQ)
    • Earlier versions of Stanford-Binet employed ratio IQ – based on mental age
    • Ratio IQ: mental age/chronological age X 100
    • Deviation IQ: reflects a comparison of the performance of the individual with the performance of others of the same age in the standardisation sample.
    • Test performance converted into a standard score with a mean of 100 and SD of 16. if an individual performs at the same level as the average person of the same age, the deviation IQ is 100. If performance is a SD above the mean for the examinees age group, the deviation IQ is 116
  • 1986 – SB-4 – A point scale, not age scale—> test organised into subsets by category of item, not by age at which most testtakers are presumed capable of responding in the way that is keyed as correct
    • based on CHC model of intelligence
    • A test component (formerly described as deviation IQ score) could be obtained
    • Test composite: a test score or index derived from the combination of, and/or a mathematical transformation of, one or more subtest scores.

Stanford-Binet Intelligence Scales: Fifth Edition

  • Ages 2-85 (or older)
  • Test yields a number of composite scores, including a full IQ scale derived from the administration of ten subtests
  • Subtest scores all have a mean of 10 and a SD of 3.
  • Based on verbal and non-verbal sub-sets
  • Composite scores and IQ.
  • Attempt made to strike equal balance between tasks requiring facility with language and tasks that minimise demands on facility with language

Psychometric Robustness

  • Internal Consistency Testing – r = 0.95 – 0.98

Test-Retest Reliability – r = 0.95-0.98

  • Inter-Scorer Reliability – ~0.90
  • Validity = high
  • Correlations between SB5 and SB:FE as well as SB5 and Wechsler batteries —> correlations high when comparing

SB5 to the SB:FE, and less then comparing to the Wechsler tests

Test administration

  • Adaptive testing: testing individually tailored to the testtaker
  • g. beginning a subtest with a question in the middle range of difficulty —> if test taker responds correctly, item of greater difficulty is posed next and vice versa
  • Helps ensure that early test or subtest items are not so difficult as to frustrate the testtaker and not so easy as to lull the testtaker into a false sense of security
  • Advantages of beginning intelligence test at optimum level of difficulty
    • Allows test user to collect the maximum amount of info in the minimum amount of time
    • Facilitates rapport
    • Minimises potential for examinee fatigue
  • Routing test: task used to direct or route the examinee into a particular level of questions e.g. in SB 5 there are 2 routing tests: (1) Object series/Matrices or Nonverbal fluid reasoning (2) Vocabulary
  • These same 2 subtests are administered for the purpose of obtaining the Abbreviated Battery IQ score
  • The routing tests contain teaching itms, which are designed to illustrate the task required and assure the examiner that the examinee understands —> not formally scored
  • Lowest level item is ‘floor’
  • Highest level item is ‘ceiling’
  • Basal level: used to describe a subtest with reference to a specific testtaker’s performance

Basal level: base-level criterion that must be met for testing on the subtest to continue

  • g. “examinee answers two consecutive items correctly”
  • For each subtest on SB5, there are explicit rules for where to start, where to reverse and where to stop (or discontinue)

Scoring and interpretation

  • Get raw score —> convert into standard score —> get composite score
  • Extra test behaviour e.g. how examinee copes with frustration, reaction to easy items etc.
  • Put scores into nominal categories (shown in pic above)

THE WECHSLER TESTS

  • David Wechsler designed a series of individually administered intelligence tests to assess the intellectual abilities of people from preschool through adulthood
  • Commonality between scales
  • All point scales that yield deviation IQs with a mean of 100 (interpreted as average) and a SD of 15
  • Testtakers performance compared with scores earned by others in that age group
  • All Wechsler tests have been evaluated favourable from a psychometric standpoint —> reliability tends to above average

Wechsler Adult Intelligence Scale – Fourth Edition (WAIS-IV)

  • Based on a points scale NOT age scale
  • WAIS, WAIR-R and WAIS-III – Verbal and Performance Scale organized with ascending difficulty.
  • WAIS-IV (2003) changed all this:
  • Core test: one that is administered to obtain a composite score

Supplemental subtest: used for purposes such as providing additional clinical information or extending the number of abilities or processes sampled.

  • Supplemental subtest can be used in place of a core test in some situations
  • g. use of a score on a particular core subtest would be questionable
    • examiner incorrectly administered a core subtest
    • assessee had been inappropriately exposed to the subtest items prior to their administration
    • the assessee evidence a physical limitation that affected the assessee’s ability to effectively respond to the items of a particular subtest
  • Improvements include more explicit administration instructions as well as the expanded use of demonstration and sample items
  • Practice (or teaching) items presumed to pay dividends in terms of ensuring low scores are actually due to a deficit and not due to a misunderstanding of directions.
  • No cultural bias
  • WAIS-IV improvement in floor and ceiling —> WAIS-III had a floor or 45, WAIS IV has floor of 40, WAIS-III had ceiling of 155, WAIS IV has ceiling of 160
  • Up to 90 years, 11 months
  • Indexes: Verbal Comprehension, Working Memory, Perceptual Reasoning, Processing Speed
  • Also a 5th index: General Ability (GAI) – overall index of intellectual ability
  • Cognitive Proficiency Index: comprised of the Working Memory Index and Processing Speed Index

The Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV)

  • More focus on the CHC model of intelligence
  • Measure of general intellectual functioning (Full Scale IQ; FSIQ)
  • Outcomes same as WAIS (FSIQ; 4 sub scores —> Verbal comprehension index, Perceptual Reasoning Index, Working Memory index, Processing Speed index)
  • Possible to derive up to seven process scores —> process score defined as an index designed to hep understand the way the testtaker processes various kinds of information
  • Does not yield separate Verbal and Performance IQ scores
  • Picture arrangement, objects assembly and mazes have been eliminated
  • Separate norms now presented for Block Design, with and without time bonuses—> represent acknowledgment that some cultures value speeded tasks more than other
  • The subtests Information, Arithmetic, and Picture Completion – formerly core subtests – now supplemental subtests
  • Standardization based on 2,200 6-16.11y olds (stratified).

WISC-IV compared to the SB5

  • Year of development
  • Norming
  • Time to complete

FSIQ and subsets

Shorts forms —> SB5 has better short form
  • CHC model and presence of g.
  • Comparability of Scores

 

**COMPARABLE ON ALL – BESIDES SHORTS FORMS

The Wechsler Preschool and Primary Scale of Intelligence – Third Edition (WPPSI-III)

  • Three composite scores may be obtained: Verbal IQ, Performance IQ, Full Scale IQ
  • Subtests labelled ‘core’, ‘supplemental’ and ‘optional’
  • Core subtests used for calculation of composite scores
  • Supplemental subtests used to provide a broader sampling of intellectual functioning (or substitute for a core test in certain circumstances)
  • Optional subtests used for calculation of optional scores e.g. general language composite
  • Structure of WPPSI-III reflects interest of test developers in enhancing measures of fluid reasoning and processing speed
  • Improved floor and ceilings —> added easier items and more difficult ones
  • Compares well with SB5 —> items correlate

Short forms

  • Issue related to Wechsler tests
  • Short form: test that has been abbreviated in length, typically to reduce the time needed for test administration, scoring and interpretation
  • Changes in a test that lessen reliability may also lessen validity
  • For that reason, decisions make on the basis of data derived from administrations of a test’s short form must, in general, be made with caution
  • When data from administration of a short form clearly suggest the need for intervention or placement, the best practice may be to “find the time” to administer the full form of the test

Wechsler Abbreviated Scale of Intelligence (WASI)

Short instrument to screen intellectual ability in testtakers from 6 to 89 years of age

Two subtest form (Vocab and block design)

Takes 15 min

Four subtests (Vocab, Block Design, Similarities, Matrix Reasoning) are WISC and WAIS type subsets that had high correlations with Full Scale IQ on those tests and are through to tap a wide range of cognitive abilities

Measures Verbal IQ, Performance IQ and Full Scale IQ

OTHER MEASURES OF INTELLIGENCE

Tests designed for individual administration

 

Tests designed for group administration

Group tests in the military

  • Army alpha test: administered to recruits who could read
  • Army beta test: administered to foreign born recruits with little knowledge of english or illiterate recruits

Group tests in schools

School ability test