Jitter is the deviation from true periodicity of a periodic signal in electronics and telecommunications, often in relation to a reference clock source.
At a tempo of 120 BPM (Beats Per Minute), continuous 16th events should occur exactly 6000 samples apart from each other when captured at 48kHz.
Jitter is more commonly used to report timing errors in very rapid clock sources.
Rhythmic timing precision can still be reported in terms of jitter.
How we perceive rhythmic feel is a psycho-acoustic principle called Beat Induction:-
Our real-time perception of rhythmic feel is hard-wired to the timing stability of the events we process directly preceding what we are hearing in that moment.
Variations in the tempo stability between previously just-heard rhythmic events is what distorts our expectation and perception of rhythmic events in the present.
Maximum Jitter as reported in the tests below is the largest rhythmic timing error measured between consecutive sixteenth step events over a continuous sixty second capture period.