The browser can record when it requested a visual change, but the pixels do not necessarily change at that exact instant. Refresh scheduling and panel processing create delay between software and visible light.
Calibrated reaction-time research often measures and corrects hardware delay when absolute timing accuracy matters.
Mouse switches, keyboard scanning, touch controllers, USB polling and system event handling all add time between the physical action and the browser receiving it.
Different devices can therefore produce different recorded results for the same person.
Suppose someone claims “all monitors add 10 ms” and subtracts 10 from every result. Real devices do not share one fixed delay. Smartphone research alone has measured large differences in combined display and touch latency across models.
A meaningful correction requires measuring the actual device under the actual configuration.
Treat the absolute number as a system-plus-human benchmark and focus on repeatability. If you use the same device, browser, input and display settings, many hardware delays remain relatively stable from session to session.
That makes changes in your own performance easier to interpret even when you cannot perfectly separate biological and hardware components.
Yes. The registered browser time includes delays in displaying the cue and receiving your input.
Only if you have a trustworthy measurement of your specific display path. Generic subtraction can create a false sense of precision.
No. Refresh rate affects frame opportunity, but panel processing, input hardware and software still add latency.
A 60 Hz display refreshes about every 16.7 ms, 144 Hz about every 6.9 ms and 240 Hz about every 4.2 ms. Higher refresh rates can reduce the waiting time before a visual change becomes visible, but they do not subtract a fixed amount from every reaction score. Browser scheduling, rendering and the exact phase of the refresh cycle still matter.
Input devices have their own latency paths. A mouse, keyboard and touchscreen can report actions at different times, and mobile browsers may have different event handling and display characteristics than desktops. Compare results across devices cautiously; for progress tracking, consistency of setup is more valuable than pretending every device is equivalent.
Mouse polling rate and local frame rate can affect when an input or visual change is processed. Internet ping usually does not affect a fully local browser reaction test because the timing happens on your device, although ping matters greatly in online games where information travels between your device and a server.