Prediction accuracy: tennis

What is checked: who wins the match. An honest probability means outcomes at 70% happen about 70% of the time.

Check on history

The players’ ratings update after every match and the estimate is made before it; the final formula of each year was trained on the years before it only. The check covers every completed ATP and WTA match of the last two years. That is how 9,894 matches from 13 October 2024 to 12 October 2026 were checked.

Model calibration: stated probability against observed frequencyEach dot is both sides' chances estimated in that range; 19,788 estimates.0%0%20%20%40%40%60%60%80%80%100%100%perfect calibrationModel probabilityObserved frequency
Each dot is both sides' chances estimated in that range; 19,788 estimates.
Model estimateEstimatesAverageHappened
0–10%3276.8%4.6%
10–20%1,09415.7%17.6%
20–30%2,06625.4%25.8%
30–40%2,93535.2%34.5%
40–50%3,47245.1%45.0%
50–60%3,47254.9%55.0%
60–70%2,93564.8%65.5%
70–80%2,06674.6%74.2%
80–90%1,09484.3%82.4%
90–100%32793.2%95.4%

How to read probabilities and calibration →

Only the model's favourite

Confidence fromShare of matchesEstimateCame true
60%65%72.7%72.7%
70%35%79.4%78.8%
80%14%86.3%85.4%
90%3%93.2%95.4%

Overall the model's most likely outcome came true in 67% of matches, with the favourite estimated at 66% on average. When the two are close, the model neither overstates nor understates its confidence.

By competition

«Honest»: the gap between the favourite’s estimate and how often it won is within the random spread for that many matches.

CompetitionMatchesFavourite came trueFavourite’s estimateProbabilities
ATP5,05366.0%66.1%honest
WTA4,84167.0%66.9%honest

Since launch

We store the last estimate before each match and never change it afterwards. Since 29 September 2026 the most likely outcome came true in 230 of 358 matches with an expected share of 66%.

CompetitionMatchesCame trueExpected
ATP19212966%
WTA16610166%

Latest 12 matches

  • Ostapenko J.Pegula J.14 October · WTA · Wuhan
    2The most likely outcome did not happen: 2Final score 2:1. Model's score: 0:2.20.5
  • Volynets K.Guo H.14 October · WTA · Wuhan
    1The most likely outcome did not happen: 1Final score 1:2. Model's score: 2:0.21.5
  • Tjen J.Snigur D.14 October · WTA · Wuhan
    2The most likely outcome did not happen: 2Final score 2:0. Model's score: 0:2.20.5
  • Ruud C.Auger-Aliassime F.14 October · ATP · Shanghai
    2The most likely outcome came true: 2Final score 0:0. Model's score: 0:2.22.5
  • Paolini J.Bartunkova N.14 October · WTA · Wuhan
    2The most likely outcome did not happen: 2Final score 2:0. Model's score: 0:2.21.5
  • Putintseva Y.Shnaider D.14 October · WTA · Wuhan
    2The most likely outcome came true: 2Final score 0:2. Model's score: 0:2, exactly right.19.5
  • Muchova K.McNally C.14 October · WTA · Wuhan
    1The most likely outcome came true: 1Final score 2:1. Model's score: 2:0.19.5
  • Jovic I.Yastremska D.14 October · WTA · Wuhan
    1The most likely outcome came true: 1Final score 2:0. Model's score: 2:0, exactly right.19.5
  • Van De Zandschulp B.Jodar R.14 October · ATP · Shanghai
    2The most likely outcome came true: 2Final score 1:2. Model's score: 0:2.22.5
  • Bouzkova M.Chwalinska M.14 October · WTA · Wuhan
    1The most likely outcome did not happen: 1Final score 1:2. Model's score: 2:0.21.5
  • Frech M.Swiatek I.14 October · WTA · Wuhan
    2The most likely outcome came true: 2Final score 0:2. Model's score: 0:2, exactly right.18.5
  • Svitolina E.Samsonova L.14 October · WTA · Wuhan
    1The most likely outcome came true: 1Final score 2:1. Model's score: 2:0.20.5

All predictions of the section →