Model performance

How the predictions have scored against actual results.

Winner called correctly

70.9%

3,673 matches, 1871-03-27 to 2026-08-15

Log loss

0.667

Lower is better; a confident wrong call costs most

Margin error

16.8 pts

Typical error in the predicted margin, 1871-03-27 to 2026-08-15

Recent form

78.3%

Weighted toward the last 90 days · an effective 59 matches

Accuracy over time
Share of matches whose winner was called correctly, by year. The thinnest year holds 38 matches, so single years move easily.

The last two years and the two before them are within sampling error of each other.

Calibration

When the model says 70%, does it happen 70% of the time?

Model saidMatchesPredictedActualGapWithin margin of error
50-60%91754.9%55.2%+0.3ppYes (±3.3pp)
60-70%84265.1%65.9%+0.8ppYes (±3.3pp)
70-80%77874.9%77.5%+2.6ppYes (±3.1pp)
80-90%63784.9%84.5%-0.4ppYes (±2.8pp)
90-100%36993.5%94.3%+0.8ppYes (±2.6pp)

Calibration across the fixture list

The same check, grouped by how far apart the two ratings were — from the closest fixtures to the most lopsided.

Rating gapMatchesPredictedActualGapWithin margin of error
0-3736855.1%59.5%+4.4ppYes (±5.2pp)
37-8136855.2%56.0%+0.8ppYes (±5.2pp)
81-12536858.5%56.8%-1.7ppYes (±5.1pp)
125-17036762.4%64.0%+1.6ppYes (±5.1pp)
170-21936767.1%68.4%+1.3ppYes (±4.9pp)
219-27536771.4%72.8%+1.4ppYes (±4.7pp)
275-34536775.8%76.0%+0.2ppYes (±4.5pp)
345-43836780.9%79.8%-1.1ppYes (±4.1pp)
438-59936786.0%87.5%+1.5ppYes (±3.6pp)
599-285636790.9%88.3%-2.6ppYes (±3.0pp)

Does the model beat the rating?

Trained on matches before 2022-11-05 and scored on the 551 it never saw. The published forecast is the blend.

MeasureRating onlyBlended (published)
Winner called correctly72.8%73.5%
Log loss0.5710.563
Brier score0.1910.188
Margin error (points)25.30824.875
Total error (points)16.61716.617

Where it was most wrong

The matches where the favourite was surest and still did not win.

DateMatchResultFavourite given
2024-11-02Belgium v Switzerland48-7Switzerland 98%
2024-10-16Paraguay v Colombia49-18Colombia 97%
2019-10-12New Zealand v Italy0-0New Zealand 96%
2024-11-16France v USA17-36France 96%
2015-09-19South Africa v Japan32-34South Africa 94%
2024-02-25France v Italy13-13France 94%
2024-11-16France v Japan20-36France 93%
2009-06-13New Zealand v France22-27New Zealand 93%
2012-06-05Australia v Scotland6-9Australia 93%
2022-03-19Wales v Italy21-22Wales 92%

These figures score the rating engine alone. The holdout below scores the blended forecast that is actually published.

Trained on 3,673 matches up to 2026-08-15, last updated 8/19/2026. How it works explains what these figures measure.

Rugby Tournament Predictor — unofficial, and not affiliated with any union, club or competition. About and sourcesForecasts are probabilities, not predictions of one result.

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