WAIS Score Comparisons and Discrepancy Analysis

Question 1

What is the primary purpose of discrepancy analysis in WAIS-IV interpretation?

Accepted Answer

To determine whether differences between index scores are statistically significant and clinically meaningful

Answer

Discrepancy analysis examines whether differences between index or subtest scores exceed what would be expected by chance, helping clinicians identify genuine cognitive strengths and weaknesses.

Question 2

In WAIS-IV tables, what two criteria are used together to determine whether a pairwise index score discrepancy is clinically significant?

Accepted Answer

Statistical significance (critical value) and base rate (frequency in the standardization sample)

Answer

A discrepancy must first exceed the critical value (statistical significance) and then be evaluated against base rate tables to determine how unusual that difference is in the normative population.

Question 3

A clinician notes that an examinee's VCI is 108 and WMI is 88. The critical value at p < .05 is 11 points. What is the correct interpretation?

Accepted Answer

The 20-point discrepancy is statistically significant, but base rate data are needed to judge clinical meaningfulness

Answer

Because 20 points exceeds the critical value of 11, the difference is statistically significant; the clinician must then consult base rate tables to determine how commonly such a difference occurs in the normative sample.

Question 4

What does the 'base rate' refer to in WAIS-IV discrepancy analysis?

Accepted Answer

The percentage of individuals in the standardization sample who showed a discrepancy of a given size or larger

Answer

Base rate data indicate how frequently a particular discrepancy occurs in the normative sample, helping clinicians decide whether a statistically significant difference is also clinically unusual.

Question 5

Which WAIS-IV index score comparison is most sensitive to detecting the effects of acquired brain injury affecting frontal-executive functions alongside processing speed?

Accepted Answer

Processing Speed Index (PSI) compared to Verbal Comprehension Index (VCI)

Answer

PSI versus VCI comparisons are especially sensitive to acquired neurological conditions because PSI tasks are highly vulnerable to brain injury while VCI, reflecting crystallized knowledge, often remains more intact.

(WAIS) Wechsler Adult Intelligence Scale Practice Test

(WAIS) Wechsler Adult Intelligence Scale Practice Test

WAIS Score Comparisons and Discrepancy Analysis