WAIS Performance Validity and Effort Indicators

Question 1

How is Reliable Digit Span (RDS) calculated?

Accepted Answer

The longest forward string plus the longest backward string where both trials were passed

Answer

RDS (Greiffenstein et al., 1994) adds the longest Forward span and the longest Backward span at which the examinee passed both trials. Low values can signal invalid performance.

Question 2

In many studies, what RDS score is the commonly cited threshold for raising concern about non-credible performance?

Accepted Answer

≤ 7

Answer

An RDS of 7 or below is a widely cited cutoff for possible poor effort. Clinicians still need to consider populations prone to false positives, such as people with intellectual disability, dementia or severe aphasia.

Question 3

What is the difference between an 'embedded' performance validity indicator and a 'freestanding' one?

Accepted Answer

Embedded indicators come from scores on existing ability subtests; freestanding tests are built only to assess validity

Answer

Embedded indicators such as RDS are taken from scores on tests already given for ability purposes. Freestanding measures such as the TOMM are separate tests designed only to detect non-credible effort.

Question 4

An examinee in a disability claim fails easy items but passes harder items of the same type. What does this pattern most strongly suggest?

Accepted Answer

Possible non-credible or inconsistent effort

Answer

Real ability usually declines as items get harder. A reversed pattern (failing easy items, passing hard ones) is a classic sign of possible feigned or inconsistent effort and should prompt formal validity testing.

Question 5

Why do professional guidelines (e.g., NAN and AACN position statements) recommend performance validity assessment in high-stakes cognitive evaluations?

Accepted Answer

Because ability scores cannot be interpreted as valid unless adequate effort is shown

Answer

Low scores could reflect real impairment or poor effort. Without evidence of valid performance, the clinician cannot tell which, so the guidelines treat validity assessment as medically necessary in forensic and disability contexts.

(WAIS) Wechsler Adult Intelligence Scale Practice Test

(WAIS) Wechsler Adult Intelligence Scale Practice Test

WAIS Performance Validity and Effort Indicators