Key evidence & numbers
| Evidence or score | What it means | What it does not mean |
|---|---|---|
| Overall difference-score effect of 0.24 | A pooled group difference in one review | A diagnostic cutoff |
| Time-per-item subgroup effect of 1.11 | A different outcome format gives a different estimate | A personal probability of ADHD |
| Your online interference score | Performance on that task and scoring rule | A clinical diagnosis |
The effect-size values come from Lansbergen and colleagues' review. Its central methodological point is that commonly used interference formulas are sensitive to the outcome measure and baseline correction. A group comparison does not become a diagnostic classifier merely because it is statistically significant. Lansbergen et al., 2007
What did the child diagnostic review find?
Homack and Riccio's review evaluates sensitivity and specificity in children and adolescents. It concludes that the Stroop test has limited utility for discriminating ADHD from other clinical groups. That is directly relevant to diagnosis: a task may differ from a healthy-control average without identifying which condition explains an individual's result. Homack, 2004
The population also matters. A child paper-and-pencil test, an adult verbal task and an online button-response game do not share one set of norms or one threshold. The clinical Stroop review documents substantial variation in versions and scoring. Scarpina et al., 2017
Why the task is not specific to ADHD
Stroop interference is an experimental phenomenon in ordinary readers. The original experiments and subsequent review explain how conflicting word and colour information changes responses without requiring a diagnosis. Experiencing interference is therefore not itself evidence of a disorder. Stroop, 1935 MacLeod, 1991
What affects it?
Why a normal-looking score does not rule ADHD out
Group averages overlap, and the diagnostic question concerns an individual's broader history and functioning, not simply one task result. The child meta-analysis' limited discrimination and the strong scoring dependence in the other review both argue against using an isolated score as an answer. A result is neither a standalone confirmation nor an exclusion. Homack, 2004 Lansbergen et al., 2007
Reliability adds another limitation. Robust experimental effects can produce comparatively noisy individual difference scores. The reliability-paradox research is relevant whenever a short cognitive task is used to make a consequential claim about a particular person. Hedge et al., 2017
Online measurement adds further uncertainty
Equipment and browser timing influence absolute response times, while task instructions and baselines influence the difference score. A consumer game has not automatically inherited the validation of a named clinical test merely because both use conflicting colour words. Anwyl-Irvine et al., 2020 Scarpina et al., 2017
International test-use guidance emphasises evidence for a test's intended interpretation and appropriate context. A clinically meaningful claim requires validation for that use and population, rather than an attractive chart or a familiar task name. International Test Commission, 2001
What is a sensible use of the test?
Use it to explore interference and compare the same task's speed and accuracy under similar conditions. If you have concerns about attention in everyday life, a game score should not decide whether those concerns deserve a professional assessment. This page explains measurement limits; it does not provide a self-diagnostic rule or treatment advice. Homack, 2004 International Test Commission, 2001
No cited paper establishes that practising this browser game treats ADHD, prevents it or makes people generally smarter. The supported interpretation remains performance on a particular conflict task. MacLeod, 1991 Scarpina et al., 2017
Try the related free test
Stroop test
Try the Stroop test as an educational task, with speed and correctness interpreted together. Its result is not an ADHD screen, a diagnosis or a substitute for a clinical assessment.
Common questions
Does a large Stroop cost mean I have ADHD?
No. A group-level effect and an individual diagnostic probability are different quantities, and the test has limited discrimination between clinical groups. Homack, 2004
Can a good score rule ADHD out?
No. These reviews do not establish that use, especially for a browser implementation with different procedures. Homack, 2004 Scarpina et al., 2017
Will practising Stroop treat attention problems?
The cited diagnostic and measurement studies do not establish a treatment benefit from this game. Lansbergen et al., 2007 Scarpina et al., 2017
Sources
- Lansbergen et al. (2007). Stroop interference and attention-deficit/hyperactivity disorder: A review and meta-analysis..
- Homack (2004). A meta-analysis of the sensitivity and specificity of the Stroop Color and Word Test with children.
- Scarpina et al. (2017). The Stroop Color and Word Test.
- Stroop (1935). Studies of interference in serial verbal reactions..
- MacLeod (1991). Half a century of research on the Stroop effect: An integrative review..
- Hedge et al. (2017). The reliability paradox: Why robust cognitive tasks do not produce reliable individual differences.
- Anwyl-Irvine et al. (2020). Realistic precision and accuracy of online experiment platforms, web browsers, and devices.
- International Test Commission (2001). International Guidelines for Test Use.
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