Standard web tests rely on Date.now() or generic interval ticks prone to frame drops and clock skew. SubMilliRT utilizes the browser's monotonic hardware clock (performance.now()), recording sub-millisecond durations relative to exact event delivery.

The "foreperiod" is the randomized latency window (2,000 ms to 5,500 ms) before the stimulus triggers. Traditional tests with fixed or narrow delays measure rhythmic prediction rather than genuine ocular-motor reaction. Early clicks trigger an invalid anticipation fault.

In esports and athletic benchmarking, consistency matters far more than an accidental lucky click. SubMilli computes the population standard deviation (σ) across all valid trials in your block. A lower σ indicates elite neuromuscular stability under pressure.

Rapid uninterrupted clicking triggers cognitive exhaustion and ocular fatigue. The 15 and 25-trial protocols enforce a 60-second recovery break every 5 trials to allow visual pigment regeneration and baseline attentional reset.