NRL Predictions for Round 1
Team Ratings for Round 1
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 season.
| Current Rating | Rating at Season Start | Difference | |
|---|---|---|---|
| Rabbitohs | 13.06 | 13.06 | -0.00 |
| Cowboys | 9.52 | 9.52 | -0.00 |
| Roosters | 9.09 | 9.09 | -0.00 |
| Storm | 4.36 | 4.36 | 0.00 |
| Broncos | 4.03 | 4.03 | -0.00 |
| Panthers | 3.69 | 3.69 | -0.00 |
| Warriors | 3.07 | 3.07 | -0.00 |
| Sea Eagles | 2.68 | 2.68 | 0.00 |
| Bulldogs | 0.21 | 0.21 | 0.00 |
| Knights | -0.28 | -0.28 | -0.00 |
| Dragons | -1.74 | -1.74 | -0.00 |
| Raiders | -7.09 | -7.09 | -0.00 |
| Eels | -7.19 | -7.19 | -0.00 |
| Titans | -8.20 | -8.20 | 0.00 |
| Sharks | -10.76 | -10.76 | -0.00 |
| Wests Tigers | -13.13 | -13.13 | -0.00 |
Predictions for Round 1
Here are the predictions for Round 1. 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 | Broncos vs. Rabbitohs | Mar 05 | Rabbitohs | -6.00 |
| 2 | Eels vs. Sea Eagles | Mar 06 | Sea Eagles | -6.90 |
| 3 | Cowboys vs. Roosters | Mar 07 | Cowboys | 3.40 |
| 4 | Knights vs. Warriors | Mar 07 | Knights | 0.70 |
| 5 | Titans vs. Wests Tigers | Mar 07 | Titans | 7.90 |
| 6 | Panthers vs. Bulldogs | Mar 08 | Panthers | 6.50 |
| 7 | Sharks vs. Raiders | Mar 08 | Raiders | -0.70 |
| 8 | Dragons vs. Storm | Mar 09 | Storm | -3.10 |
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, I don’t get Game 4: Knights – 0.28, Warriors 3.07 = Prediction Knights 0.70. Could you help me by spelling out the maths in English (rather than algebra)? Kind regards, Ken
10 years ago
The difference is due to the home ground advantage, which for this match was 4 points:
– 0.23 – 3.07 + 4 = 0.65. I actually keep more decimal places when I do this sum though so the value given in the post is slightly different, that is 0.70 rather than the value 0.65 calculated above.
10 years ago
The other games I assumed a Home Advantage (HA) of 3 points for. This worked for all but Knights-Warriors match. I was obviously wrong with assumption because the math wouldn’t work using HA 3. You say HA ‘for this match was 4 points’. Therefore, David, I ask why was HA for this match 4 points? Why did HA value vary for this match? Will HA value vary match to match (3,4 or 5 or so) depending on value you assign?
10 years ago
There are two different values, one for games involving two teams from the same country, another if the two teams are from different countries. For the NRL, that means games involving the Warriors have a different value to other games.
10 years ago
Thank you kindly.
10 years ago