If swing were simply a 2:1 ratio, learning the number would solve the problem.
Expert performance says otherwise.
A useful teaching approximation describes swung eighth notes as long-short, often close to a triplet-like 2:1 relation. But measurements of expert jazz drummers show that the ratio changes with tempo.
The ratio moves
Research by Anders Friberg and Andreas Sundström found that slower performances could use more unequal long-short timing, while faster tempi tended toward ratios closer to equality. Later studies of expert jazz drumming found the same broad pattern: professional players exercise fine timing control without preserving one fixed ratio everywhere.
The relationship is recognisable because it adapts, not because it refuses to change.
Proportion can depend on context
School ratio problems often teach preservation: double both quantities and keep the same relationship. Similar triangles and direct proportion reward that instinct.
Jazz swing introduces another possibility. The ratio itself can be a function of context.
swing ratio = f(tempo, player, phrase, context)
This is mathematically richer than declaring one constant. It asks which relationship is fundamental and which parameter is allowed to move.
Measurement is evidence, not the music
Researchers can measure onset times, timing ratios and microtiming. Those measurements are valuable because they test assumptions against performance.
They do not reduce swing to one scalar. Articulation, accent, phrasing, ensemble interaction, history and style remain part of the musical experience.
The number can describe a feature without becoming the mechanism that creates the whole.
Expert consistency can contain variation
There is an educational lesson here. Consistency is often mistaken for repeating the same procedure unchanged.
But experts sometimes preserve the larger relationship by changing the smaller one. The drummer adjusts timing as tempo changes. The strong Mathematics student changes method when the structure of the problem changes.
Fidelity to the whole can require variation in the parts.
Jazz is an African American musical tradition with histories and meanings no timing equation can contain.
Mathematics contributes a narrower correction: a useful approximation should remain willing to move when the evidence moves.
Further reading
Acoustical Society of America — Jazz Drummers’ Swing Ratio in Relation to Tempo
Utrecht University — Swing Once More
Scientific Reports — Microtiming Deviations and Swing Feel in Jazz