April 12, 2022

NRL Predictions for Round 6

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Team Ratings for Round 6

For a second week all the result predictions have been correct which seems to have generated a lot of interest and some comments.

Please be aware this is a rare event. I have been predicting Super Rugby and NRL for 10 years and getting all results correct is rare enough but never before have I had all results correct two weeks in a row. For me it is simply an example of a fact about rare events. Even if the probability of an outcome is low, if you repeat the action many times it is likely that the outcome will occur.

Regarding the correctness of my predictions, all I will say is that over the course of a season, it is likely that I will get a bit over 70% of correct results. That is what I have observed over a number of years for different competitions but that can vary a lot as well. For many years I was unable to get to 70% correct predictions for the NRL. Currently my predictions for the Rugby Premiership are only 54% correct.

My purpose in posting these predictions has been to illustrate the efficacy of a very simple statistical method of forecasting.  The predictions are also an illustration of what can happen with random events. It can appear that there is a consistent pattern which can be exploited even over what seems to be a considerable time. Never believe that you can beat randomness: it will come back to bite you.

Against my usual practice I won’t publish or comment on all submitted comments this week.

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
Storm 17.05 19.20 -2.20
Panthers 14.57 14.26 0.30
Rabbitohs 12.83 15.81 -3.00
Sea Eagles 8.94 10.99 -2.10
Eels 5.06 2.54 2.50
Roosters 2.77 2.23 0.50
Sharks 1.65 -1.10 2.80
Titans -1.00 1.05 -2.00
Raiders -2.65 -1.10 -1.50
Knights -5.47 -6.54 1.10
Dragons -7.73 -7.99 0.30
Warriors -8.45 -8.99 0.50
Broncos -8.74 -8.90 0.20
Cowboys -9.44 -12.27 2.80
Bulldogs -10.03 -10.25 0.20
Wests Tigers -11.34 -10.94 -0.40

 

Performance So Far

So far there have been 40 matches played, 29 of which were correctly predicted, a success rate of 72.5%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Knights vs. Sea Eagles Apr 07 6 – 30 -9.60 TRUE
2 Warriors vs. Cowboys Apr 08 25 – 24 7.50 TRUE
3 Broncos vs. Roosters Apr 08 20 – 24 -9.40 TRUE
4 Raiders vs. Storm Apr 09 16 – 30 -17.20 TRUE
5 Rabbitohs vs. Dragons Apr 09 24 – 12 25.20 TRUE
6 Titans vs. Eels Apr 09 20 – 26 -2.50 TRUE
7 Sharks vs. Wests Tigers Apr 10 30 – 4 14.60 TRUE
8 Bulldogs vs. Panthers Apr 10 12 – 32 -21.90 TRUE

 

Predictions for Round 6

Here are the predictions for Round 6. 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 Raiders vs. Cowboys Apr 14 Raiders 9.80
2 Rabbitohs vs. Bulldogs Apr 15 Rabbitohs 22.90
3 Panthers vs. Broncos Apr 15 Panthers 26.30
4 Sea Eagles vs. Titans Apr 16 Sea Eagles 12.90
5 Storm vs. Sharks Apr 16 Storm 18.40
6 Roosters vs. Warriors Apr 17 Roosters 16.70
7 Dragons vs. Knights Apr 17 Dragons 0.70
8 Eels vs. Wests Tigers Apr 18 Eels 19.40

 

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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 »

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