About SkillDrills

SkillDrills is an independently built and self-funded project. It is not affiliated with, endorsed by, or connected to any game publisher, esports organisation, clinic or university, and nothing here is a commercial product for any third party.

You can reach the person who maintains it at support@skilldrills.online. Corrections to anything factual on this site are genuinely welcome — if a figure or a citation here is wrong, say so and it will be fixed or removed.

Every drill records events using the browser's performance.now() high-resolution clock, entirely on your own device. Rendering runs on a canvas driven by requestAnimationFrame, so the drill is paced by your display rather than by a fixed timer.

What that measurement contains is you plus your hardware. It is not a laboratory instrument, and three things it cannot separate out are worth knowing before you read anything into a score:

• Timer resolution. Browsers deliberately coarsen high-resolution timers as a Spectre-era side-channel mitigation — typically to around 1 ms.
• Display quantization. A stimulus cannot appear between frames. That is about 16.7 ms per frame at 60 Hz, 6.9 ms at 144 Hz and 4.1 ms at 240 Hz.
• Input polling. A mouse polling at 125 Hz reports a click up to about 8 ms late; at 1000 Hz, about 1 ms.

Taken together, that means a drill here resolves real differences of roughly 5 ms and upward. Treat anything finer as measurement noise, and compare your own runs on the same machine rather than your number against someone else's on different hardware. Any site claiming sub-millisecond precision from a web browser is overstating what the platform can do.

Scores, personal bests and settings are written to your browser's local storage and stay there. They are not uploaded, not pooled, and not visible to anyone but you — clearing your browser data deletes them permanently. Cookie-less traffic and performance measurement on the website is described in the privacy policy.

Because of that, this site has no aggregate performance statistics and will never publish any. You will not find “average user scores X”, player counts, star ratings or testimonials here, because there is no honest way to produce them. The benchmark tables on drill pages are labelled as editorial guides drawn from published literature, not as norms measured from visitors.

See the privacy policy for the full detail.

Reaction time, saccadic eye movement, smooth pursuit and choice reaction are genuinely researched subjects, so the figures quoted across this site are taken from published work and cited by name with a DOI in the References panel on each drill page. Nothing is attributed to this site's own users, and no statistic, study or quotation is invented to make a page look more authoritative.

If a citation here does not say what the page claims it says, that is a bug. Report it to support@skilldrills.online and it will be corrected.

These drills are training and entertainment tools. They are not a medical device, not a clinical assessment, and not a diagnostic test for any condition. Nothing here diagnoses, treats, prevents or screens for anything, and a score should never be used to reason about your health. If you are concerned about your vision, reaction speed or cognition, talk to a qualified clinician.

All 81 drills are free and open at the drill directory. The most-used starting points are the reaction time test and the reaction speed drills.