par72 · reconstructed from public scorecards

The Curve They Sealed

The USGA never publishes the "expected score" behind your handicap — the hidden primitive their whole engine leans on. We rebuilt it from 9,237 rounds of ordinary play. Each dot is an index band, sized by how many rounds sit in it; the gold line is the curve we fit; the star is the USGA's one published number.

Expected Differential = 4.92 + 0.949 × Handicap Index  ·  R² = 0.9934  ·  9,237 rounds

an index band (dot size = rounds) our fitted curve ★ USGA's published anchor
10152025303540152025303540 index 11: 38 rounds, avg diff 16.439index 12: 93 rounds, avg diff 16.056index 13: 79 rounds, avg diff 17.286index 14: 92 rounds, avg diff 17.307index 15: 129 rounds, avg diff 18.271index 16: 233 rounds, avg diff 20.315index 17: 314 rounds, avg diff 21.332index 18: 432 rounds, avg diff 22.074index 19: 491 rounds, avg diff 22.694index 20: 797 rounds, avg diff 24.187index 21: 940 rounds, avg diff 24.965index 22: 932 rounds, avg diff 25.808index 23: 950 rounds, avg diff 26.742index 24: 965 rounds, avg diff 27.981index 25: 861 rounds, avg diff 28.474index 26: 641 rounds, avg diff 29.327index 27: 515 rounds, avg diff 30.008index 28: 185 rounds, avg diff 30.714index 29: 152 rounds, avg diff 32.816index 30: 138 rounds, avg diff 33.543index 31: 53 rounds, avg diff 34.466index 32: 30 rounds, avg diff 35.33index 33: 45 rounds, avg diff 37.296index 34: 58 rounds, avg diff 37.674index 35: 27 rounds, avg diff 39.189index 36: 7 rounds, avg diff 35.857 USGA's one published anchor: 17.0 our curve here: 18.2 (off +1.2, ~7%) Handicap Index — the number they call your deficiency Expected Score Differential (18 holes)

We reconstructed the number the USGA won't publish — from public scorecards alone.

Their one published example lands within about 7% of our line, at the sparse low end of a women's league that runs a touch hotter than their universal table. The shape is unmistakably theirs. A sealed primitive, rebuilt in the open — which is the entire point: nothing here is hidden.

Every round binned by its GHIN-stamped Handicap Index; mean official Score Differential per band; weighted least-squares over 9,237 rounds. A Handicap Index is the mean of your best 8 of 20 — so it sits about four strokes below your true average, the gap they call "expected score." Reproducible by anyone holding the rounds. That is the difference.  ·  Read the Declaration →