Rugby World Cup Predictions for the Semi-finals
Team Ratings for the Semi-finals
The basic method is described on my Department home page.
Here are the team ratings prior to this week’s games, along with the ratings at the start of the Rugby World Cup.
| Current Rating | Rating at RWC Start | Difference | |
|---|---|---|---|
| New Zealand | 28.42 | 29.01 | -0.60 |
| South Africa | 22.84 | 22.73 | 0.10 |
| Australia | 20.85 | 20.36 | 0.50 |
| England | 16.43 | 18.51 | -2.10 |
| Ireland | 15.97 | 17.48 | -1.50 |
| Wales | 13.85 | 13.93 | -0.10 |
| Argentina | 11.27 | 7.38 | 3.90 |
| France | 8.96 | 11.70 | -2.70 |
| Scotland | 5.94 | 4.84 | 1.10 |
| Fiji | -2.19 | -4.23 | 2.00 |
| Samoa | -4.15 | -2.28 | -1.90 |
| Italy | -6.37 | -5.86 | -0.50 |
| Tonga | -8.84 | -6.31 | -2.50 |
| Japan | -9.10 | -11.18 | 2.10 |
| USA | -17.13 | -15.97 | -1.20 |
| Georgia | -17.74 | -17.48 | -0.30 |
| Canada | -17.89 | -18.06 | 0.20 |
| Romania | -19.44 | -21.20 | 1.80 |
| Uruguay | -31.67 | -31.04 | -0.60 |
| Namibia | -33.29 | -35.62 | 2.30 |
Performance So Far
So far there have been 44 matches played, 37 of which were correctly predicted, a success rate of 84.1%.
Here are the predictions for last week’s games.
| Game | Date | Score | Prediction | Correct | |
|---|---|---|---|---|---|
| 1 | South Africa vs. Wales | Oct 17 | 23 – 19 | 10.10 | TRUE |
| 2 | New Zealand vs. France | Oct 17 | 62 – 13 | 16.60 | TRUE |
| 3 | Ireland vs. Argentina | Oct 18 | 20 – 43 | 7.50 | FALSE |
| 4 | Australia vs. Scotland | Oct 18 | 35 – 34 | 16.50 | TRUE |
Predictions for the Semi-finals
Here are the predictions for the Semi-finals. The prediction is my estimated expected points difference with a positive margin being a win to the first-named team, and a negative margin a win to the second-named team.
| Game | Date | Winner | Prediction | |
|---|---|---|---|---|
| 1 | South Africa vs. New Zealand | Oct 24 | New Zealand | -5.60 |
| 2 | Argentina vs. Australia | Oct 25 | Australia | -9.60 |
David Scott obtained a BA and PhD from the Australian National University and then commenced his university teaching career at La Trobe University in 1972. He has taught at La Trobe University, the University of Sheffield, Bond University and Colorado State University, joining the University of Auckland, based at Tamaki Campus, in mid-1995. He has been Head of Department at La Trobe University, Acting Dean and Associate Dean (Academic) at Bond University, and Associate Director of the Centre for Quality Management and Data Analysis at Bond University with responsibility for Short Courses. He was Head of the Department of Statistics in 2000, and is a past President of the New Zealand Statistical Assocation. See all posts by David Scott »
Using a regression on difference in ranks to predict difference in scores based on all world cup teams, then adjusting for the residuals not be random as particular teams over/underperform compared to their rank and play better against low ranked vs high ranked teams, I would say New Zealand beat South Africa by a 6 to 30 range centring on 18, Argentina to beat Australia by a -1 to 21 range (the negative 1 is actually a win to Australia) centring on 10.
9 years ago