Assesment - WAIS Flashcards
Describe the rationale and development of the Wechsler Adult Intelligence Scale (WAIS)
im was to produce high quality psychological test of intelligence.
Valid ; Reliable; Standarized .
- To predict one performance, in work and education. This enables placement in special schools for gifted children or low IQ. after Stanford Binet, different framework of understanding of the construct of intelligence.
- to measure ones functionality, particularity to predict change in functionality after an ABI. Developed to test WW2 veterans, as they experience trauma and ABI’s and loss of function.
Its wide use is mainly for its excellence in capacity as a test
Describe the changes over the Wechsler Adult Intelligence Scale (WAIS) various revisions
Preserve the longstanding history of the scores…
Update the norms/Flynn effect (new norm population)
Age corrected scores; A later edition devised a new test for children.
Update theoretical foundations (eg: working memory, processing speed, fluid intelligence)
Improve psychometric properties and Enhance clinical utility (ensure that updated with DSM and clinal populations)
User friendly - iPad.
Increase developmental appropriateness??
Describe the changes with an emphasis on the WAIS-IV
WAIS IV -
- Address specific issue, such as corrections for education, indications of symptom consistent answers, implications of a low score..
- Overall intelligence weighted differently across the four sub-scales
- Orientation to axis… Introduction of GAI and CPI which better discriminates between what may or may not be effected by ABI
Test operating characteristics of the WAIS-IV What does the following measure ? VCI PRI WMI PSI FSIQ - full scale GAI CPI
Sub tests - different aspects
Verbal Comprehension Index Perceptual Reasoning Index Working Memory Index Processing Speed Index Full scale - most reliable General Ability Index (GAI) Cognitive processing index (CPI))
More difficult items will often require multiple cognitive processes. Conflations in top levels..
EXPLAIN THE FLYNN EFFECT;
Flynn (1987) 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???
HOW TO USE THE SCORES!!
less likely to make an error in your clinical diagnosis if you
use the most reliable indicators.
Most reliable to least reliable
- FSIQ
- index score
- sub-test score - Can not make a conclusion here.
What does the WAIS test?
‘the capacity of the individual to act purposefully,
to think rationally, and to deal effectively with his (or her) environment’(Wechsler, 1944, p. 3).
Tests the constructs that represent facets of overall intelligence.
can not directly tell us what is wrong in brain.
Kaufman’s APPROACH
1.Use composite scores and clusters as they are more reliable and carry more weight (not sub-tests)
2.Uses base rate data to evaluate the clinical
meaningfulness of clustering index called variability
- Interpret within the context of validated theory. (ideally same as used in WAIS manual)
- use of supplemental measures to test hypotheses about significant subtest variation or outlier scores
Can we Test hypotheses with the WAIS-IV?
What should we use it to asses?
Fundamental flaw if use clients perspective or referral to form a hypothesis. do not do ‘process’ approach based on referral question. it precludes other approaches that may lead to other outcomes. Clients do not know what they don’t know. must consider all explanations.
Use the test.
- determine the client’s current status,
- determine the client’s status prior to the insult or injury
- determine the client’s future status.
absence of evidence is not evidence of absence.
if you didn’t measure you cant conclude.
use standard approach, standard approach instrument.
say there was a compromise on.. and not on.. andas a consequence the nature of deficits are found to be e statistically significant and unusual patterns of compromise that they feature pertaining to __ (illness/ABI)
The FSIQ - how to calculate and can we use it?
Consider the four indices
Subtract the lowest from the highest and determine if the size of the standard score difference is less than 1.5 SDs (< 23 points).
If YES = FSIQ interpreted and employed.
If NO = GAI should be employed in instead.
WHAT IS THE GAI and when to use it.
The General Ability Index (GAI) provides a summary score less sensitive than FSIQ to working memory and processing speed,
i.e. the skills most affected by ABI. (every ABI will impair this)
*use the GAI when a WMI or PSI deficit
If there is such a discrepancy, GAI is a more accurate measure, and should be used in preference (but not for ID determination - not for intellectual disability as must use full scale = no compensation) exists.
how can we calculate the GAI and decide whether it is interpretable
calculate difference between VCI and PRI is less than 1.5 SDs (< 23 points).
if YES, If it is, then GAI interpreted and employed.
If NO, the summary/assesment as it is not meaningful.
WHAT is the CPI and when to use it?
The CPI is a person’s proficiency for processing certain types of information, most notably those functions that are measured by the WMI and PRI. ***not 100% agreement on grouping together.
To compute the CPI we must sum the scaled scores for the subtests in the WMI and the PSI
Is the size of the difference between WMI and PSI
<1.5SDs (<23 points)?
If YES; then CPI can be calculated and interpreted
If NO; comparison cannot be made
Is the GAI-CPI discrepancy large?
is the difference 23 points or greater
Are the indices unitary?
determine whether the size of the differences among the sub test scaled scores within the VCI is too large (i.e. the differences are greater than 1.5 SDs, i.e. 5 points)
if not then issue
*subtests are the individual tests (3 per index)
