Assessment L5 - WAIS-IV Flashcards
What are the goals for the revision of the WAIS-IV?
-Preserve the history of the scales
-Update the norms/Flynn effect
-Update theoretical foundations
-Enhance clinical utility
-Improve psychometric properties Increase user-friendliness
-Increase developmental appropriateness
What is the ‘reliable change’ index?
Predicts the nature of improvement as a consequence of practice effects.
–> so you can measure/ test for the degree of which someone performs above the expected improvement.
what was the WAIS-IV Normative Sample?
- Ages- 16-90
- Normative sample: N = 2200
- 200 examinees per age band for ages 16-69
- 100 examinees per age band for ages 70-90
- National sample stratified by: Sex, Education Level, Ethnicity, Region
What are clinical validation studies?
These studies validate that the WAIS is doing what we’d want an IQ test to do - EG. diagnosing intellectual disability and giftedness.
- Making sure that items at the bottom and top of the scale are working just as well.
WAIS is not a tool for diagnosis - it simply shows that clinical conditions affect intellectual functioning.
eg. Depression, dementia, MCI, TBI, ADHD, Intellectual disability, Autism, Learning Disability, Asperger’s.
Why do we use age corrected scores?
- In WAIS-R, the scaled score for each sub test was based on the scores of a non-impaired reference group of examinees, aged 20-34. not good!!
- age adjusted scaled scores were used for all other ages - but couldn’t be used to determine IQ
Problems:
- Optimal performance does not consistently occur between 20-34
- may lead to interpretive errors - bc score ranges change as participants age
- older people perform worse on processing speed - can’t just standardise on young people bc older people are almost doing 2SD lower, and you’d deem them compromised when they’re intact.
want to compare old people to old people.
- not possible to use this comparison using the WAIS-III, but with the WAIS-IV this comparison was again possible!! bc WAIS-IV standardises by comparing age with age.
Is education adjusted for in the WAIS-IV
No. Only age is adjusted for.
- Education accounts for 25% of variance in FSIQ scores on WAIS-R (on WAIS-III sub-tests: Information 23.3% through to 0.9% on Symbol Search: i.e. high/verbal low/performance
- Educational adjustment will be important particularly for high functioning/highly educated clients
What is the Flynn Effect?
- Norms in US become out-dated at a rate of 3 IQ points per decade i.e. 1⁄3 to 1⁄2 of a point per year
- Possibly due to: education; nutrition; health; improvement in speed due to computer exposure???
- Therefore advisable to use newest norms, because they give a more accurate figure
What re the goals in updating the theoretical foundations in WAIS-V??????
Eliminate dual IQ/index score structure
- Consistent with WISC-IV
- Consistent measures of WM within the Wechsler memory and intelligence scales - in the WAIS III they were completely different. now the Wais measures verbal WM, and wechsler memory measures visuo-spatial WM
Enhance measure of fluid intelligence
- Develop additional measure of fluid reasoning: Figure Weights
- they will take on whatever construct and measures they find to measure intellect well.
Enhance measure of working memory
- Revise arithmetic and digit span to emphasise WM
- arithmetic test is actually a test of WM rather than a test of calculation - because it presents a discursive question which requires a lot of working memory to remember the components - requires a lot of information to be in line to be able to answer the question.
Enhance measure of processing speed
- Develop additional PS subtest: Cancellation
Enhance theoretical foundations of the scale
- Focus upon CHC theory (but not as much or as closely as Kevin McGrew’s Woodcock Johnston)
What is the cattell-horn-carroll gf-gc Theory?
- WAIS predates CHC
- Suggests that there are 10 broad abilities that lead to intelligence.
- 10 broad –> 69 narrow abilities
- Keith 5 Factors - fluid intelligence, crystiallised intellgence, short term memory, visual processing and processing speed.
What are some factors not well measured by the WAIS-IV - if all all?
- Auditory or spatial memory or new learning
- Creativity
- Daily living skills
- Facial recognition/processing
- Bodily-kinaesthetic intelligence
- Musical intelligence
- Planning ability
- Practical (inter-personal) intelligence - Intra-personal intelligence
- Receptive vocabulary
- Emotional intelligence
- Visual closure and gestalt
What is FSIQ and what does it include?
Full Scale Intelligence Quotient.
- Verbal comprehension index
- Perceptual reasoning index
- Working Memory Index
- Processing Speed Index
What are some general assessment considerations?
- NO test exists that measures only a SINGLE construct
- Measures of GENERAL ABILITY require development of appropriate ITEM-DIFFICULT GRADIENTS:
The degree of construct penetrance varies across the item set –> as you move from low to high questions of the test, should be measuring the same thing the whole way through.
More difficult items will often require multiple cognitive processes
- Neuropsychological test often have NON NORMAL DISTRIBUTIONS.
> Negatively skewed = use percentile ranks.
>Affects reliability
>Standard scores may be misleading, so percentiles have to be used - Memory tests are NOT SOLELY MEMORY TESTS, they
measure other abilities
>Language
>Visual-perceptual-spatial abilities
What is the difference between index score contributions to FSIW for the WAIS-III and WAIS-IV
The constitution of the IQ was changed.
The WAIS-III had uneven spread of things across the set of skills.
WAIS-IV is more evenly spread, VCI=30, PRI=30, WMI=20. PSI=20.
Better because it is more fair - due to people innately being better at different things.
Describe the Frequency distribution of IQ scores
IQ/indices: Mean = 100, sd = 15 Subtest scaled scores : Mean = 10, sd = 3 68% of the population within 1 sd of mean (i.e. between 85-115 (7-13) 95% within 2 sds [i.e. 70- 130 (4-16)]
Effect sizes are usually as units of sd (thus a large effect size of 0.8 = 0.8 X 15(3)= 12(2.4)»_space;»effect of moderately severe brain damage = 0.5
What does obtaining one or two low scores mean?
- Obtaining one or two low scores on a battery of tests occurs FREQUENTLY in the general population (multivariate vs. univariate base rates)
- One or two and sometimes more low scores do not necessarily indicate impairment or atypical function
- We need to consider the level of premorbid functioning of the individual
NEVER base diagnoses on subtests due to individ differences.
Need to have at least 2 impairments then consider premorbid functioning.
NO ONE gets consistently 10’s (mean) across all subtests - variability is intrinsic to the measure
23% of people with 120+ IQ scared 7 or less on one or more subtests, but 2% got one or more low scores on an index!!!
