Every comprehensive evaluation we conduct includes performance validity measures — not because we suspect a particular client, but because it's the professional standard for producing results that hold up to scrutiny.
Clients occasionally ask why part of their evaluation seems to test something unrelated to their presenting concern — a memory task that seems oddly simple, or a set of items that feels almost too easy. Attorneys and school evaluation teams ask a related but sharper question: how do we know these results are trustworthy enough to inform a legal decision, an accommodation, or a diagnosis with real consequences? Both questions have the same answer: performance validity testing (PVT), also called effort or symptom validity testing — a standard, expected component of every comprehensive evaluation we conduct, for every client, regardless of the reason for referral.
In this article
What Performance Validity Testing Actually Is
Performance validity tests are measures embedded within — or added alongside — a standard testing battery to determine whether someone's scores reflect genuine effort and engagement, rather than being artificially lowered (or, less commonly, artificially inflated). Without this check, a low score on a memory or attention test is ambiguous: it could reflect a real impairment, or it could reflect reduced effort, distraction, fatigue, or something else entirely. Validity testing is what allows an evaluator to say, with confidence, which explanation actually fits.
The American Academy of Clinical Neuropsychology's 2021 consensus statement is direct on this point: the current professional standard is that all clinical and forensic evaluations must proactively address the degree to which testing results are valid, not just cases where invalid results are suspected in advance (AACN, 2021).
Why Every Evaluation Includes It
This is the point clients and referral sources most often misunderstand: validity testing is not something we add because we doubt a particular person. It's built into every battery for the same reason a lab draws a control sample alongside a diagnostic blood test — a result is only meaningful once you know it can be trusted. Skipping this step wouldn't make an evaluation more respectful of the client; it would make it less defensible for everyone who ultimately relies on the results, including the client themselves.
How It Actually Works
| Type | What it is | Example |
|---|---|---|
| Standalone measures | A brief, dedicated task included specifically to assess effort, often designed to look harder than it actually is | A short recognition memory task with a very high expected pass rate even for people with genuine impairment |
| Embedded measures | Validity indicators derived from patterns within tests already being given for clinical reasons, at no extra time cost | An unusual pattern of errors on a standard attention or memory subtest |
Most comprehensive evaluations use several of each type across the battery, since relying on a single indicator increases the chance of a false conclusion in either direction.
Common Myths About Effort Testing
Reality: it's standard in every comprehensive evaluation. In fact, research has found that people involved in litigation were no more likely to fail a performance validity test than people who weren't — undercutting the assumption that this is primarily a forensic tool aimed at litigants (Martin & Schroeder, 2020).
Reality: an invalid profile has many possible explanations — pain, fatigue, poor sleep, test anxiety, a language barrier, or genuine severe impairment can all produce it. It's a flag for further clinical judgment, not an automatic conclusion.
How Common Is Invalid Performance, Really?
A 2020 review found the median base rate of invalid performance in everyday clinical (non-forensic) settings was around 15%, ranging from about 5% in populations where invalid results weren't anticipated up to 50% among patients with medically unexplained symptoms (Martin & Schroeder, 2020, Archives of Clinical Neuropsychology). This matters directly for our ADHD evaluations: a 2023 study of adults referred for ADHD diagnosis found a meaningful rate of cognitive underperformance in that population specifically, reinforcing why validity measures are built into every ADHD battery we administer, not added as an afterthought (Dong et al., 2023, Journal of Clinical Medicine).
What an Invalid Profile Does — and Doesn't — Mean
When validity measures suggest a profile isn't fully reliable, it doesn't automatically mean someone is malingering. The most widely used framework for actually reaching that more serious conclusion — developed by Slick, Sherman, and Iverson in 1999 and still the standard reference over two decades later — requires multiple independent sources of evidence, not a single failed measure, before malingering can be formally considered (Slick, Sherman, & Iverson, 1999, The Clinical Neuropsychologist).
Why This Matters for Attorneys and Schools
For evaluations tied to litigation, disability determinations, or school accommodations under IDEA or Section 504, the credibility of the underlying data is often as important as the conclusions themselves. A report that documents validity testing gives opposing counsel, hearing officers, and school evaluation teams fewer grounds to challenge the findings on methodological terms — because the evaluator has already addressed the question of whether the results can be trusted, using a documented, peer-reviewed standard rather than clinical impression alone.
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Schedule a Consult Contact UsFrequently Asked Questions
Does including validity testing mean you suspect me of lying?
No. Validity measures are included in every comprehensive evaluation for every client, as a matter of professional standard practice, not because of any suspicion about a specific individual.
What happens if my results show reduced validity?
It prompts a closer clinical look at possible explanations, such as fatigue, pain, poor sleep, or test anxiety, well before any conclusion about intent is considered. A single indicator is never treated as definitive on its own.
Is performance validity testing only used in legal cases?
No. Research has found that people involved in litigation are no more likely to fail these measures than people who aren't, and validity testing is a standard part of everyday clinical evaluations, not just forensic ones.
Will validity testing add time or cost to my evaluation?
Most validity indicators are embedded within tests already part of a standard battery, so they add little to no additional time. Any standalone measures used are typically brief.
Can genuinely impaired people fail a validity measure?
It's uncommon but possible, particularly with severe impairment, certain medical conditions, or significant fatigue. This is exactly why evaluators interpret validity results alongside the full clinical picture rather than in isolation.
Why does this matter for school accommodations or legal proceedings?
Documented validity testing strengthens the credibility of an evaluation's findings, giving schools, hearing officers, and courts a transparent, peer-reviewed basis for trusting the results rather than relying on clinical impression alone.
Sources & Further Reading
- American Academy of Clinical Neuropsychology. (2021). AACN 2021 consensus statement on validity assessment. The Clinical Neuropsychologist.
- Martin, P. K., & Schroeder, R. W. (2020). Base rates of invalid test performance across clinical non-forensic contexts and settings. Archives of Clinical Neuropsychology, 35(6), 717–725.
- Slick, D. J., Sherman, E. M. S., & Iverson, G. L. (1999). Diagnostic criteria for malingered neurocognitive dysfunction: Proposed standards for clinical practice and research. The Clinical Neuropsychologist, 13(4), 545–561.
- Dong, H., Koerts, J., Pijnenborg, G. H. M., Scherbaum, N., Müller, B. W., & Fuermaier, A. B. M. (2023). Cognitive underperformance in a mixed neuropsychiatric sample at diagnostic evaluation of adult ADHD. Journal of Clinical Medicine, 12(21), 6926.
This article is for informational purposes and is not a substitute for individualized clinical or legal guidance.
Alan Jacobson, Psy.D., MBA, is a licensed clinical psychologist and Director of the Foresight Psychological Institute, the parent company of Precision Psychological Testing.
