How Many Rounds Before Strokes-Gained Data Is Reliable?
TL;DROne round tells you nothing. Five rounds tells you direction. Ten rounds tells you truth.
ATX Golf Performance··5 min read
Variance is enormous in amateur golf. One round of strokes-gained can show you "losing strokes to driving" when really you had two unlucky lies. Here's the sample size that makes the data actionable.
The reliability table
| Rounds tracked | What the data tells you | Confidence |
|---|---|---|
| 1 | Almost nothing | Low |
| 3 | Rough direction | Low |
| 5 | Your weakest category | Medium |
| 10 | Trends and gaps | Good |
| 20 | Stable averages | High |
| 50+ | Skill-level evidence | Very high |
Source:Mark Broadie, Every Shot Counts — sample-size analysis of strokes-gained variance; corroborated by Arccos round-level data.
What to do early
Don't make swing changes after 1 or 2 rounds of data. After 5, you can identify the weakest category with reasonable confidence. After 10, you can compare against handicap benchmarks and trust the result.
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