Use a laptop or desktop with a physical keyboard if possible (touch screens work too). Sit in a quiet room, close other applications, and stay in this tab for the whole task. There is a short practice first.
Report details · optional
Shown on the report and stored with the screening record. Use initials or a code, not full names.
Answers, results and report details are recorded by OpenScreener to monitor and improve the service. Privacy
About this screener — evidence, source, what inspired it
Continuous performance tests (CPTs) are computerised attention tasks. In this not-X version, letters flash one at a time and the person presses for every letter except X. Missed letters (omissions) index inattention, presses for X (commissions) index impulsivity, and reaction-time variability indexes the consistency of attention — the same measures that commercial CPTs report.
Evidence · unvalidated
The CPT paradigm is long established, but this browser implementation has no normative data yet, so results are reported as raw metrics without percentiles. Commercial CPTs themselves have modest diagnostic accuracy for ADHD and are recommended only as supplementary evidence.
Inspired by
- Conners CPT 3 · MHS
The not-X paradigm (respond to all letters except X) with variable inter-stimulus intervals. - TOVA / QbTest · The TOVA Company / Qbtech
Computerised attention metrics: omissions, commissions, response time, and variability.
Not affiliated with these publishers. No items, norms or scoring materials from them are used — only publicly described constructs and procedures. Scores are not interchangeable.
Source & licence
OpenScreener contributors. Open CPT, v0.1, 2026. Paradigm: Rosvold HE et al. A continuous performance test of brain damage. J Consult Psychol. 1956;20(5):343–350; not-X variant after Conners.
Licence: MIT (code) / CC BY 4.0 (protocol)