Observed Events vs Calculated Metrics
InputMetric separates values the browser directly reports from values the site calculates. A button press, keyboard event or wheel direction can be observed when the browser delivers it to the page. Polling-rate estimates, reaction time, reset gaps and event jitter are calculated from the timing of those events.
Calculated browser values are not direct access to device firmware or electrical signals.
Timing
Timed tools use a monotonic browser clock such as performance.now() for local elapsed-time calculations. Samples crossing a visibility interruption are discarded because background scheduling can distort results.
Where pointer coalescing APIs are available, additional movement samples may be used. Browser and platform support vary.
Mouse Polling Rate
The polling-rate page estimates pointer-event frequency visible to the browser. Firmware may be set to 125, 500, 1000, 4000 or 8000 Hz, but the browser may group, coalesce or schedule events differently. The displayed value is therefore browser-observed.
Keyboard Timing
Standard keyboard events expose a key code, state and timestamp. They do not expose physical switch travel, Hall-effect sensor position or the firmware scan cycle. Rapid Trigger results describe event timing, not actuation or reset distance.
Privacy
Raw input events are processed locally by the interactive tools. Keyboard pages do not reconstruct or transmit typed sentences. Google Analytics is present for page analytics; raw key sequences and pointer trails are not included in application analytics events.
Repeatability
One browser measurement can be noisy. Repeat runs and compare medians or averages while keeping the browser, device and system conditions as similar as possible. A single best or worst sample should not be treated as a diagnosis.
When Dedicated Hardware Is Needed
USB bus timing, electrical switch bounce, sensor scan timing, physical actuation distance and full click-to-photon latency need lower-level software or specialized equipment. A normal web page cannot replace those methods.