ADHD Reaction Time Test | Attention Lapses and Reaction Variance, Measured

A free, browser-based test that measures the two reaction patterns most strongly associated with ADHD in published research: attention lapses (very slow trials) and high run-to-run variance.

What the Research Actually Looks At

Clinical Continuous Performance Tests (CPT) do not focus only on average reaction time. They look at reaction-time variance and the frequency of unusually slow responses — exactly what SERO logs on every trial.

This Test Is Not a Diagnosis

SERO is a precision-timing benchmark, not a medical instrument. A high variance score does not mean you have ADHD; only a qualified clinician using validated tools can diagnose it. Use SERO as a self-tracking baseline you can show a doctor.

Run your attention baseline

FAQ

Is this a medical ADHD test?

No — it is a free reaction-precision benchmark inspired by CPT-style metrics. Diagnosis requires a clinician.

What metrics does it show?

Median, fastest, slowest and standard deviation across all trials, so you can see consistency in addition to raw speed.

Can I take it on medication?

You can run it whenever you like — before and after a dose can be a useful self-tracking comparison, but interpret results with your clinician.