Across 7,362 player-seasons of Marin-area and San Francisco USTA NorCal adult league, players who won a line at sectionals moved up 21.3% of the time, against 6.0% for those who reached sectionals and won nothing.
Players whose team never qualified moved up 6.6% of the time, the same rate as going and losing. Each season is followed into the next year's published rating.
A player counted as moving up held a higher published NTRP rating the following year, which is USTA's verdict rather than the Desk's. It does not show that USTA weights sectionals more heavily than an ordinary Tuesday, and none of these rates is a forecast about any particular player.
The first two bars are the finding. A player whose team qualified, who travelled to the tournament, who played there and who won no line at all goes up at 6.0%, and one whose team never qualified at 6.6%.
Being there changes nothing. Winning a line once there is worth about 3.6×, and that is the whole of the effect people attribute to the trip.
The obvious complaint is that sectionals collects good players, and I think it is a real one. It is large, too: qualifiers win around two-thirds of their regular-season lines, against a bit under half for everyone else.
But it cannot explain the two bars above, because every player in that comparison qualified — all 2,460 of them are on teams good enough to get there, which is exactly what holds team quality fixed. Reaching sectionals is something a team does, and winning a line there is something a player does.
Promotion rates fall steeply as the level rises, so the split is cut again by the Desk level each player carried into the season, read off their first line.
The widest gap is in the band where most of this league plays, where a player who went and lost moved up 1.4% of the time and one who won a line 15.0%.
It does not show that USTA weights sectionals more heavily than an ordinary Tuesday. A player who wins at sectionals may simply be better than their regular-season record showed, and any year-end calculation would find that out from the same matches without treating them specially.
Both explanations produce this table and the data cannot separate them. What it does say is narrower: a sectional result carries information a win-loss record does not.
2022: 19.3% · 2023: 18.3% · 2024: 25.0% · 2025: 21.6%
That is the winners' rate by season boundary. No single year carries the result or contradicts it, which is what a cause built into the system looks like rather than a run of results.
So the belief is right, with the interesting half missing from the way it is usually said. What moves a rating is not the trip but the line a player won once they got there.
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Grounded — every figure above is a count over a stated denominator. No estimates, no model output: just match results and what they add up to.
Scope. USTA NorCal adult league for Marin County and San Francisco, seasons 2022–2025, each followed into the next year's published rating. It is those two areas, not NorCal and not a national figure.
Who is counted. A player-season enters only if the same person carries a published NTRP rating in both years — a promotion is not observable otherwise — and only if they played at least six regular-season lines, because a rate over two or three lines is mostly about who those opponents happened to be. 7,362 player-seasons clear both.
What "sectionals" means here. A scorecard the source marks as a sectional day. Playoff days are counted with the regular season, not with sectionals, and are not analysed separately here.
Method. Every figure above was produced by the SQL recorded in docs/research/records/sectionals.json and re-run against the live database before this page was built. The record also carries the confounds that were checked and could not be removed, including a logistic regression adjusting for level, record and volume. Reproduce with npx tsx scripts/measure-research-record.ts.