Super 15 Predictions for Round 9
Team Ratings for Round 9
The basic method is described on my Department home page. I have made some changes to the methodology this year, including shrinking the ratings between seasons.
Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.
| Current Rating | Rating at Season Start | Difference | |
|---|---|---|---|
| Sharks | 7.29 | 4.57 | 2.70 |
| Crusaders | 6.27 | 8.80 | -2.50 |
| Chiefs | 4.65 | 4.38 | 0.30 |
| Waratahs | 4.21 | 1.67 | 2.50 |
| Brumbies | 4.00 | 4.12 | -0.10 |
| Bulls | 3.58 | 4.87 | -1.30 |
| Stormers | 0.66 | 4.38 | -3.70 |
| Hurricanes | 0.51 | -1.44 | 1.90 |
| Reds | -0.78 | 0.58 | -1.40 |
| Blues | -1.33 | -1.92 | 0.60 |
| Cheetahs | -3.35 | 0.12 | -3.50 |
| Force | -3.47 | -5.37 | 1.90 |
| Highlanders | -4.52 | -4.48 | -0.00 |
| Lions | -4.99 | -6.93 | 1.90 |
| Rebels | -5.73 | -6.36 | 0.60 |
Performance So Far
So far there have been 49 matches played, 30 of which were correctly predicted, a success rate of 61.2%.
Here are the predictions for last week’s games.
| Game | Date | Score | Prediction | Correct | |
|---|---|---|---|---|---|
| 1 | Highlanders vs. Rebels | Apr 04 | 33 – 30 | 5.60 | TRUE |
| 2 | Brumbies vs. Blues | Apr 04 | 26 – 9 | 8.20 | TRUE |
| 3 | Hurricanes vs. Bulls | Apr 05 | 25 – 20 | 0.30 | TRUE |
| 4 | Reds vs. Force | Apr 05 | 29 – 32 | 6.40 | FALSE |
| 5 | Cheetahs vs. Chiefs | Apr 05 | 43 – 43 | -4.60 | FALSE |
| 6 | Lions vs. Crusaders | Apr 05 | 7 – 28 | -5.40 | TRUE |
| 7 | Stormers vs. Waratahs | Apr 05 | 11 – 22 | 2.10 | FALSE |
Predictions for Round 9
Here are the predictions for Round 9. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.
| Game | Date | Winner | Prediction | |
|---|---|---|---|---|
| 1 | Highlanders vs. Bulls | Apr 11 | Bulls | -4.10 |
| 2 | Reds vs. Brumbies | Apr 11 | Brumbies | -2.30 |
| 3 | Chiefs vs. Rebels | Apr 12 | Chiefs | 14.40 |
| 4 | Force vs. Waratahs | Apr 12 | Waratahs | -5.20 |
| 5 | Cheetahs vs. Crusaders | Apr 12 | Crusaders | -5.60 |
| 6 | Lions vs. Sharks | Apr 12 | Sharks | -9.80 |
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 »
Hi David,
61% correct predictions is not bad, considering the form book has been out the window for a lot of games so far. Interested to know how close/accurate your margin predictions are too?
Also, if you had (more) data, say from the beginning of super rugby (1996)…would you use it? Do you think it would improve your predictions, or do you think more recent data gives a more accurate reflection of a teams form and therefore results older than a couple of seasons have no bearing on present day results?
11 years ago
It has been a difficult season so far with the Stormers and Cheetahs dropping substantially and some surprising results from the Force and Rebels.
I don’t think more data would offer much. I already have quite a number of years, and exponential smoothing downweights past data exponentially. Even when the downweighting is by a factor not much less than one, after a few years further past results wouldn’t have any substantial effect.
11 years ago
Strange our win % are the same. I apply the following rules:
1) Never go against Crusaders
2) Chiefs are new Crusaders
3) Blue Bulls at home
4) Jake White in Durban
5) Pick against the team travelling from AUS/NZ to SA or other way round
11 years ago
I agree with Eddie. The inter-continental trip has an effect. David, you already differentiate HG advantage between inter-state and intra-state, don’t you think a further refinement to differentiate HG advantage if its an inter-continental match might improve results?
11 years ago
That would be a possibility. I would probably do it as an alternative to what I do now, rather than add another parameter. It is certainly worth investigating. I can see some problems though. For example a NZ team going to Perth is a pretty long haul, and is an SA team going to Perth the same as an SA team going to Dunedin?
11 years ago