Issues in the Interpretation of Intelligence Tests WISCIV

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Issues in the Interpretation of Intelligence
Tests (WISC-IV)

• Updated Fall, 2004

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Acknowledgements

• The information in this PowerPoint is gleaned
  from many sources, including the textbooks that
  you are using for PSYC 631.
• Of particular importance are texts by Alan
  Kaufman and his associates (Intelligent Testing
  with the WISC-III and Essentials of WISC-IV
  Assessment), Randy Kamphaus (Clinical
  Assessment of Child and Adolescent Intelligence)
  and Jerome Sattler ( Assessment of Children
  Cognitive Applications (4th Ed.))

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Before We Begin Some Rules for the Road

• Ground your conclusions in behavior
• Err on the conservative side
• Do not make unnecessary pejorative comments about
  children
• Test your hypotheses carefully
• Advocate for children
• Think clearly write clearly
• Keep the faith

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4 important things to keep in mind

• Tests are samples of behavior
• Tests do not directly reveal traits or capacities
• Tests (including subtests) must have adequate
  reliability and validity
• Test scores can be affected by a myriad of
  factors that makes interpretation difficult

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4 more things to remember

• Test results must be interpreted in context.
• Test results depend on the childs cooperation
  and motivation
• Tests supposedly measuring the same ability may
  produce different scores
• Individual subtests, groups of subtests, factor
  indexes, etc. do not measure unique cognitive
  processes, abilities, or constructs.

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9 Major Principles of Integrative Test
Interpretation (Kamphaus)

• 1. Collect and integrate data from numerous
  sources
• 2. Corroborate conclusions with multiple data
  sources
• 3. Support conclusions with research
• 4. Interpretation should be individualized
• 5. Emphasize reliable and valid conclusions

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9 Principles (cont.)

• 6. De-emphasize subtest profile analysis
• 7. Minimize calculations
• 8. View interpretation as an iterative process
• 9. Emphasize apriori over aposteriori
  interpretation

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9. Emphasize apriori over aposteriori
interpretation

• Apriori means based on a hypothesis or theory
  rather than on experiment or experience
  deductive.
• Aposteriori means reasoning from effects to
  causes inductive.
• Implications for test interpretation?
• Example of child referred with TBI

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The Information-processing model and the WISC-IV

• This model has four components
• 1. Input
• 2. Integration
• 3. Storage
• 4. Output

• This model provides examiners with a conceptual
  framework for interpreting IQ scores, factor
  indexes, and scaled scores

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Information-Processing Model
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Wechsler and Information Processing (cont.)

• INPUT How information from the senses enters the
  brain.
• Generally, VCI and WMI subtests are auditory and
  PRI and PSI subtests are visual, though these
  also have auditory processing demands (e.g.,
  directions)
• Input aspect of Wechsler is really more subtle
  than a simple auditory/visual dichotomy why?

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Information Processing cont.)

• Integration Interpreting and processing the
  information examples from WISC?
• Storage Storing the information for later
  retrieval examples from WISC?
• Output Expressing information via language or
  muscle (motor) activity. Applications to WISC
  subtests?

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Four WISC factors and the IP model

• VC and PR These are cognitive factors and are
  best viewed as measures of integration
• PS Best viewed as output
• WM ?? Depends on how you interpret it
• Intelligence is typically evaluated in terms of
  the integration/processing component of the IP
  model
• However, input and output are also important

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11 Steps to an achieving an absolutely Fabulous
Profile

• Of WISC-IV scores, that is.
• You must integrate this approach with clinical
  skill, theoretical understanding, and knowledge
  of the WISC-IV

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Before you start Rules for the Road

• In explaining an assessment result, no more
  assumptions should be made than necessary
• Do not reify test scores, or fail to consider
  context
• Beware of the subtest-specific capacity trap

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More rules for the road

• The clinical impressions of examiners do not
  cut it for supporting interpretations of a
  persons IQ scores you need EMPIRICAL support
• Shared subtest hypotheses used in ipsative
  approaches are problematic no validity, no
  research base (see 6)

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A few more rules for the road

• Because of problems with grouping high or low
  subtests (Kaufman approach), some would say that
  the lowest level of profile analysis, if
  conducted at all, should concern scale or
  composite (index) scores (Kline et al., 1996).
• For referrals for academic problems, treat
  intelligence and achievement tests as co-equals
  measuring different and reciprocal kinds of
  achievements

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WISC-IV structure 3-level hierarchy
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Highlights of Kaufmans new (2004) interpretation
framework

• Links ipsative and normative analyses rather than
  focusing on one or the other
• Excludes the interpretation of individual
  subtests
• Uses base-rate data to evaluate the clinical
  meaningfulness of score variability
• Grounds interpretation in CHC Theory
• Provides guidance on use of supplemental measures
  to test hypotheses about subtest variations or
  outlier scores

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Highlights of Kaufmans new (2004) interpretation
framework

• Focuses on the four WISC-IV indexes to summarize
  a childs overall intellectual ability
• Next, both Normative and Personal (Ipsative)
  Strengths and Weaknesses among the Indexes are
  identified this is the most reliable and
  meaningful information about the childs WISC-IV
  performance
• Finally, there are optional interpretive steps
  for new WISC-IV Clinical Clusters

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Step 1 Create a Score Summary Sheet

• Include the childs Standard scores for the FSIQ
  and the 4 Indexes
• Report the score, confidence interval, percentile
  rank, and descriptive category
• Do not present these as exact scores in the body
  of the report, however!
• For the subtests, report only the percentile rank
  associated with the childs obtained standard
  scores

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Step 1 Create a Score Summary Sheet

• Need to adopt a descriptive category system
• Alternatives
• WISC manual
• Sattler
• Essentials text pp. 124-125

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Step 2 Determine the best way to summarize
overall intellectual ability

• Step 2a Look at all 4 indexes. Subtract lowest
  from highest. Is the difference less than 23
  points?
• YES? FSIQ can be interpreted as reliable and
  valid estimate of global intelligence
• NO? Too much variability in indexes FSIQ score
  is no longer useful. Go to Step 2b

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Step 2 Determine the best way to summarize
overall intellectual ability

• Step 2b See if an abbreviated General Ability
  Index (GIA) score may be used to describe overall
  intellectual ability
• Is the size of the standard score difference
  between the VCI and PRI less than 23 points?
• YES? Calculate the GIA score (Appendix F of the
  Essentials text
• NO? Cannot calculate GIA. Go to Step 3.

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Step 3 Determine whether each of the 4 Index
scores is unitary (interpretable)

• Step 3a Determine if the variability (scatter)
  in the VCI Index is unusually large. Subtract
  highest subtest scaled score from the lowest
  subtest scaled score. Is the difference less than
  5 points?
• YES? Then the ability presumed to underlie VCI
  is unitary and may be interpreted
• NO? Cannot interpret as a single ability
• Steps 3b, 3c, and 3d Repeat for other 3
  indexes. Use the same criterion of less than 5
  points.

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Step 3 Determine whether each of the 4 Index
scores is unitary (interpretable)

• What to do if an index or indexes is
  uninterpretable due to too much scatter?
• See if subtests can be arranged differently using
  another classification system (e.g., Bannatyne)
• Check to see if all subtests in the index have
  scaled scores of 12 or higher ? notable
  integrity
• Check to see if all subtests in the index have
  scaled scores of 8 or less ? notable limitation
• In the rare instance that all four indexes are
  not interpretable, go to Step 7.

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Step 4 Determine normative strengths and
normative weaknesses in the Index profile

• Please note that only unitary indexes identified
  in the previous step are included in this
  analysis
• If the index score is greater than 115, then the
  ability measured by the Index is a normative
  strength.
• Less than 85 normative weakness
• 85-115 within normal limits

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Step 5 Determine personal strengths and
personal weaknesses in the Index profile

• Step 5a Compute the mean of the childs Index
  standard scores (round to nearest tenth)
• Include all indexes, even if previously
  determined to be uninterpretable
• Step 5b Subtract the mean of all Index standard
  scores from each interpretable Index standard
  score
• Use Table 4.3 in Essentials text to determine
  whether the size of the difference between an
  interpretable Index and the mean of all Indexes
  is significant. Use .05 level and age levels.

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Alternate Interpretation Frameworks

• The following steps were developed before the
  publication of Essentials of WISC-IV
  Assessment.
• These procedures are optional and should not
  replace the framework described in the prior
  slides and in Chapter Four of Essentials of
  WISC-IV Assessment.
• For yet another interpretation procedure, consult
  Chapter 4 of Assessment of Children WISC-IV
  and WPPSI Supplement by Jerome Sattler

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STEP 1 Report and describe the WISC-IV Full
Scale IQ score FSIQ

• Most reliable score (split-half r .97
  test-retest r .93)
• Usually considered the g score
• Confidence Interval (Use 95 level)
• Percentile rank
• Descriptive category
• How to word this in the report
• Why should we go beyond this score?

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STEP 2 Report and describe the VCI (Verbal
Comprehension) score

• VCI is a measure of verbal concept formation,
  verbal reasoning, and knowledge acquired from
  ones environment
• Most reliable of 4 indexes (.94)
• INF is supplemental less emphasis on acquired
  knowledge here
• Report with corresponding confidence interval,
  percentile rank, and descriptive category (as
  with the FSIQ in Step 1).

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STEP 3 Report and describe the PRI (Perceptual
Reasoning) score

• PRI is a measure of perceptual and fluid
  reasoning, spatial processing, and visual-motor
  integration.
• Greater emphasis here on fluid reasoning than on
  the WISC-III Performance Scale or Perceptual
  Organization Index
• Report with corresponding confidence interval,
  percentile rank, and descriptive category (as
  with the FSIQ in Step 1).

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STEP 4 Report and describe the WMI (Working
memory) score

• WMI provides a measure of working memory
• This is the ability to temporarily retain
  information in memory, perform some operation or
  manipulation with it, and produce a result.
• Involves attention, concentration, mental
  control, and reasoning
• Essential component of other higher-order
  cognitive processes
• Report score as with FSIQ, etc.

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STEP 5 Report and describe the PSI (Processing
speed) score

• PSI provides a measure of childs ability to
  correctly scan, sequence, or discriminate simple
  visual information
• Faster processing may conserve working memory
  resources
• This index/composite also measures short-term
  visual memory, attention, and visual-motor
  coordination
• Report score as with FSIQ, etc.

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Step 6 Determine if there is a significant
difference between the examinees verbal and
performance abilities

• Refer to the first line of the Discrepancy
  Comparisons page of the protocol (p. 2)
• Analyze the difference between the VCI and the
  PRI scores at the .05 level.
• Consider whether the observed difference between
  the VCI and PRI scores is statistically
  significant or not, and what this means in terms
  of processing skills.
• If the difference is significant, go to Step 7.

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Step 7 Determine if the observed VCI/PRI
difference is interpretable

• This is the issue of index subtest scatter.
• If there is abnormally large scatter within an
  index score, it is unlikely that you can infer a
  single ability or set of abilities (verbal
  comprehension or perceptual reasoning) that
  affect the score on that index
• Abnormal scatter for VCI 5 or more points
• Abnormal scatter for PRI 6 or more points

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Step 8 Determine whether the VCI-PRI difference
is abnormally large

• Refer again to first line of Discrepancy
  Comparisons on p. 2 (VCI-PRI)
• For base rate, consider differences that occur
  in 15 or less of the population as abnormally
  large.
• For overall sample, this is 19 points
• Alternate approach Double critical value
• Obviously, only significant VCI-PRI differences
  can be abnormally large as well
• Remember that average VCI-PRI difference for all
  examinees is 10-11 points.

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STEP 9 Interpret the meaning of the global
Verbal and Nonverbal Dimensions (represented
generally by VCI and PRI)

• Here you consider the meaning of the verbal and
  nonverbal dimensions of the test and what any
  significant differences might indicate
• Remember that although Wechsler believed in
  general intelligence (g), he did feel at times
  it was necessary to look at verbal and nonverbal
  functioning separately
• This is much harder to do on the new WISC-IV

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STEP 9 The Verbal/Nonverbal Dimensions

• Verbal Perceptual
• Preference for verbal vs. nonverbal content
• Difficulty coping with novelty (Sternberg)
• High achievement motivation
• Hemispheric specialization

• Perceptual Verbal
• Preference for nonverbal vs. verbal content
• Linguistic differences
• Speech or language impairment
• Hearing impairment
• Hemispheric specialization

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STEP 9 The Verbal/Nonverbal Dimensions

• Verbal Perceptual
• Poor spatial ability
• Fine-motor problems
• Deliberate response style
• Negative reaction to time pressure
• Poor long-term memory and/or word retrieval
  problems

• Perceptual Verbal
• Good spatial ability
• Learning disability (however, this profile is of
  virtually no value in making the diagnosis of a
  learning disability because it does not address
  ability/achievement discrepancies

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More information on hypotheses regarding
Verbal/Performance differences

• Old CV ? V/P differences mean brain damage (Left
  damage ? Verbal is low Right damage ?
  Performance is low
• New CV ? A simple one-to-one relationship between
  Wechslers V-P dichotomy and the two cerebral
  hemispheres just does not exist
• Search for characteristic profiles is very
  frustrating and inconclusive (1987 study)
• Two notable exceptions 1. PV for numerous
  populations of delinquents 2. Very high PV for
  Native Americans (29-34 pts.)

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More information on hypotheses regarding
Verbal/Performance differences

• One solid conclusion The Verbal and Performance
  scales differ mostly by input and output but are
  quite similar in terms of mental processes and
  storage requirements.
• Input-output for Verbal scale ? auditory-vocal
  and for Performance scale ? visual-motor
• But much in common in terms of mental processes
  and storage requirements (next slide)

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More information on hypotheses regarding
Verbal/Performance differences

• Knowledge Base?
• INF (Verbal)
• PC (Performance)
• STM
• DS (Verbal)
• COD (Performance)
• Social Understanding
• COMP (Verbal)
• PA (Performance)

• Concept Formation
• VOC (Verbal)
• BD (Performance)
• Verbal Mediation
• SIM (Verbal)
• PA (Performance)
• Speed of Processing
• AR (Verbal)
• SS (Performance)

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More information on hypotheses regarding
Verbal/Performance differences

• Verbal vs. Nonverbal Content (V/
• Highly supported by research
• Wechslers original intent most parsimonious
• Look for poor (or strong) academic achievement
  record, poor/good articulation
• Delayed/precocious language development interest
  (or lack of interest) in mechanical
  skills/hobbies
• Good/poor conversational skills, reading interest

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More information on hypotheses regarding
Verbal/Performance differences

• Linguistic differences (PV)
• Consider for any kid for whom English is a second
  language
• Also consider dialect, cultural differences
• Hearing impairment (PV)
• Novelty (VP)
• Achievement motivation (VP)

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More information on hypotheses regarding
Verbal/Performance differences

• Hemispheric specialization (VP PV)
• This is a big area of research dating back to
  Gazzanigas work in the 1960s
• E.g., BD often used by split-brain researchers as
  exemplary measures of spatial-holistic processing
  abilities of the right hemisphere
• However, the left-right brain dichotomy has not
  been consistently demonstrated in children

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More information on hypotheses regarding
Verbal/Performance differences

• Spatial ability (PV or VP)
• Look for history of vision problems, difficulty
  in academic areas that require spatial skills
  (geometry
• Traumatic neurological insult or congenital
  damage to visual/spatial processing areas of the
  brain
• Poor scores on Bender, VMI

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More information on hypotheses regarding
Verbal/Performance differences

• Motor problem (VP)
• Deliberate response style (VP)
• Time pressure (VP)
• Learning disability (PV)
• Long-term memory/Word retrieval (VP)

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STEP 10 Identify any significant strengths and
weaknesses within the 4 indexes

• THIS STEP IS NOT ON YOUR PROTOCOL ANALYSIS PAGE!
• First, compute the average of the childs four
  factor composite scores (not the sum of scaled
  scores)
• Then, determine whether each of the four indexes
  differ significantly from the childs mean
  composite standard score
• Values to use are VCI (/- 9), PRI (/- 9), WMI
  (/- 9), and PSI (/- 11).

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STEP 10 Identify any significant strengths and
weaknesses within the 4 indexes (cont.)

• Refer to Steps 2-5 for what is measured by each
  of the indexes
• Also review information in subsequent slides
• These index strengths and weakness may mesh
  fairly closely with identification of subtest
  strengths and weakness in Step 11.

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The WM Index

• L-N SEQ and DS are the subtests on this factor
• No different than situation where L-N SEQ and DS
  are both relative strengths in the profile
  analysis (Step 11)
• Beware of the distractibility interpretation!
• Must look at behavioral observations, background
  information, and the details of the childs
  performance on the two subtests

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Possible WMI interpretations

• Attention
• Concentration
• Anxiety
• Sequencing ability
• Number ability

• Planning ability
• Short-term memory
• Visualization

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The PS Index

• As with WM, need to look at multiple data sources
• Most obvious interpretation is processing speed
  (wow! Really?)
• Types of speed differ mental speed on SS but
  psychomotor speed on COD
• Also check out visual-motor coordination poor
  use of pencil can slow the kid down
• As with WM, consider noncognitive factors as well
  as cognitive (see next slide)

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Possible PSI factor interpretations

• Processing speed
• Visual-motor coordination
• Motivation
• Reflectiveness
• Compulsiveness
• Visual memory
• Planning ability

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STEP 11 Identify significant strengths and
weaknesses in the subtest profile

• Ipsative approach to identifying childrens
  relative strengths and weaknesses in those
  aspects of cognitive functioning assessed by the
  WISC
• Reference point is the childs mean performance,
  either on all the subtests together, or
  separately on the Verbal and Performance scales

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STEP 11 Identify significant strengths and
weaknesses in the subtest profile

• Refer to p. 2 of protocol Determining Strengths
  and Weaknesses
• Remember that differences that are not
  significant are, indeed, not significant
• Dont forget to use the normative frame as needed
  to help put subtest strengths and weaknesses in
  context

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STEP 11 Generate hypotheses about the
fluctuations in the subtest profile

• Try to find shared abilities behind two or more
  subtests
• Remember that these are tentative need to look
  at the big picture
• Do not simply rattle off a list of abilities from
  the book/tables

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I. Bannatynes Categories (WISC-III and WAIS-III
only)

• Armchair division of subtests into 4 groups
  that has been very popular
• Lots of application to learning- and
  reading-disabled children and adults
• They do fairly well on the Spatial triad, but
  demonstrate weakness in the Sequential and
  Acquired Knowledge areas

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Bannatynes Categories (1 2) for the WAIS-III

• Verbal Conceptualization Ability
• SIM
• VOC
• COMP

• Spatial Ability
• PC
• BD
• OA
• MR

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Bannatynes Categories 3 4 for the WAIS-III

• Sequential Ability
• AR
• Digit Span
• Digit Symbol-Coding
• L-N Sequencing

• Acquired Knowledge
• INF
• AR
• VOC

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II. Expanded Horn Model Carrolls 3-stratum
model (WISC-III and WAIS-III

• Many similarities except that Horn does not
  include g (general intelligence)
• Crystallized Intelligence
• INF
• VOC
• COMP
• SIM
• PA

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Expanded Horn Model Carrolls 3-stratum model
(WISC-III WAIS-III

• Fluid Intelligence
• MR
• BD
• OA
• SIM
• PA
• AR

• Broad Visualization
• PC
• BD
• OA
• MR

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Expanded Horn Model Carrolls 3-stratum model
(WISC-III WAIS-III)

• Short-term Memory
• AR
• DS
• L-N SEQ

• Broad Speediness
• DS-COD
• SS
• OA

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Rapaports Clinical Model (WAIS)

• Stressed that clinicians should look at subtest
  strengths and weaknesses relative to mean subtest
  score for person assessed
• Also stressed that IQ had to be seen in the
  overall context of personality development and
  environmental influences
• However, many of his and his disciples
  conclusions are not backed up by research

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III. Rapaports Clinical Model (WAIS)

• Very influential model from clinical psychology
• Rapaport, Gill, and Schaefer (1945-46)
• Stressed that IQ was neither fixed or constant
• Stressed the influence of personality,
  environmental stimulation, emotional stimulation,
  defensive styles, culture, psychopathology, and
  brain injury on the maturation and expression of
  intelligence

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Rapaports Clinical Model (WAIS)

• Example High Digit Symbol and low Digit Span
  score ? a person who seems to be controlling
  strong and pressing anxiety by excessive
  activity. When we find the reverse pattern . . .
  we are usually confronted with an essentially
  depressed person who is attempting to ward off
  recognition of depressive affect in a hypomanic
  way, usually via denial, but not necessarily
  through activity and acting out behavior.

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Rapaports Clinical Model (WAIS)

• Memory
• INF
• VOC

• Concept Formation
• VOC (verbal)
• SIM (verbal)
• MR (nonverbal)
• BD (nonverbal)

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Rapaports Clinical Model

• Visual Organization
• PC
• PA
• MR

• Visual-Motor Integration
• BD
• OA
• Digit Symbol

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Rapaports Clinical Model (WAIS)

• Orienting Response
• Digit Span (attention)
• AR (concentration)
• L-N Sequencing (concentration)
• PC (concentration)
• PA (anticipation)

• Object Assembly (anticipation)
• Digit-Symbol Coding (concentration)
• SS (concentration)

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Verbal profiles that occur with reasonable
frequency (1) WISC-III

• Verbal Scale
• INF 12
• SIM 11
• AR 5 (W)
• VOC 14
• COMP 12
• DS (6) (W)

• Issue?
• VCI vs. FD factors
• Verbal Scale split
• Which is the better measure of the persons
  verbal abilities? VIQ or VCI?

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Verbal profiles that occur with reasonable
frequency (2) WISC-III

• Sheilas Verbal (97)
• INF 5
• SIM 16
• AR 6
• VOC 8
• COMP 13
• DS (14)

• Barbaras Verbal (97)
• INF 11
• SIM 7
• AR 11
• VOC 13
• COMP 6

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Verbal profiles that occur with reasonable
frequency (2) WISC-III

• Acquired Knowledge (Bannatyne)
• Culture deprived versus pushed ahead?
• INF, AR, VOC depend on environment, culture,
  long-term memory
• How useful is Sheilas Verbal Scale score?

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Verbal profiles that occur with reasonable
frequency (3) WISC-III

• Davids Verbal
• INF 7
• SIM 11
• AR 12
• VOC 8
• COMP 12
• DS 8

• Alfreds Verbal
• INF 11
• SIM 7
• AR 8
• VOC 12
• COMP 8
• DS 11

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Verbal profiles that occur with reasonable
frequency (3) WISC-III

• This is reasoning versus recall of information
• The reasoning subtests generally involve more
  problem-solving and application of old knowledge
  to new situations
• The recall subtests generally involve more
  retrieval of stored information