NRL - The season so far
We are seven rounds into the new NRL season, and despite pledging not to spend any time writing articles this year (I had to try and placate the wife) I have decided it would be useful to see how we are tracking, and writing about it can help!
The start of the season has been a little indifferent, albeit still profitable, with the return after 7 rounds standing at +14% on bets made, and a profit of $455 if you bet $100 on each recommended bet.
TipBetPro Player Ratings
As discussed in previous articles the main determinant of our predictions is the TipBetPro player ratings, which are a unique score allocated to each player based on a number of player based statistics, including their experience.
The sum of each teams 17 players each week is subtracted from the opponents to obtain the predicted margin. This in turn is adjusted for factors such as form, home ground advantage and ladder position to obtain the final recommendation.
After 7 rounds we can look at the average TipBetPro Player Ratings awarded to each team and also compare this to the current ladder position:
As regular followers would know, the model loves the Cronulla Sharks, and has had them consistently ranked as our number one team both last year and this year. This is primarily a factor of their experience and the consistent squad selection (ie few injuries). On average, ignoring the other team based factors, the model has the Sharks beating the next best ranked team, the Sydney Roosters, by 4.4 points, and the lowest ranked team, the Knights by a whopping 31.2 points.
If we compare the TipBetPro Player Ratings to ladder position we can see that the Sharks are not top, albeit only just behind the Dragons and Storm, so our model could be argued to overly rate the Sharks (noting they have won us more money than any other team as the bookies tend to rate them lower – a fair bit lower).
Interestingly the model would appear to over rate the Roosters (2 place difference) Broncos (3 place difference) and Sea Eagles (4 place difference) too, whilst underrating the Storm by 4 places and the Dragons by 6 places.
For the Storm this is simply because their younger, less experienced players are guns, and the model tends to not reward this as there is little data to go on. For the Dragons, they have simply been this year’s bolter, performing better than I think most models/pundits would have thought.
Dynamic nature of the model
Clearly the analysis above is a bit crude, and the use of averages is always a bit misleading. The model is based on the teams named each week, so will flex as the teams change, as well as individual player stats change (note the actual player rankings involve some statistical differences between teams being capped so the totals below are illustrative in nature).
The Top 4 ranked teams on averages are the Sharks, Roosters, Broncos and Raiders, and their weekly TipBetPro player ratings are as follows:
As can be seen the Sharks (yellow line CS) actually started the year slightly behind the Roosters (grey line SR) and have just been pipped by the Raiders as the number one ranked team in round 8 (orange line CN). The Raiders have had a barnstorming couple of weeks led by the high scoring Jordan Rapana. The Raiders are certainly a team who have started to pick up and repay some of the preseason faith.
Top 5 - 8
The remaining teams in the top 8 are shown in the following chart.
The biggest fallers are the Cowboys (brown line NQ) who have fallen almost 15 points since round one, led by the out of JT. The Sea Eagles (green line MW) and Dragons (orange line SI) are the surprise packages thus far and both are seeing a climb in their ratings. As mentioned earlier the Storm (blue line MS) tend to be under rated but are slowly climbing (possibly too slowly!).
Outside the 8, 9 – 12
The teams outside the 8 are led by the Bulldogs, Eels, Warriors and Panthers.
The Warriors (brown line NZ) are definitely the movers in this group and buoyed by the presence of Foran in the past few weeks. Interestingly for the Panthers (green line PN) losing players such as Matt Moylan in round 6 had a big impact. The ins led by Klemmer have seen the Bulldogs (grey line CB) ratings jump in round 8, back to their round 1 levels.
The spoon contenders
Making up the numbers are the following four teams:
The Knights (black line NC) didn’t even make the 80 point cut off for the graph until round 3, but to be fair they have been improving week on week (the blip in round 8 should have been in round 7 when Buhrer was a late withdrawal (not updated!). The Titans (blue line TI) are struggling and were actually the lowest ranked team in rounds 6 and 7. Souths and Tigers have been pretty consistent….consistently poor.
We will continue to monitor the model and as always are open to constructive suggestions. We tend not to make changes on the fly as the algorithms are based on extensive statistical back testing and short term reactions have not been validated statistically. That said, the Storm stand out as a team we could back in more and maybe even our old favourites the Dragons!!
Best of luck for the rest of the season.