Saturday 4:35pm (Etihad Stadium) After demolishing North Melbourne in emphatic fashion in Round 1, Adelaide head to Etihad Stadium on Saturday to take on Collingwood. We were as surprised as anyone with Collingwood’s strong performance in Round 1, where they smashed Brisbane for three quarters before allowing the Lions to make the score line look respectable late. We were, like many, on Brisbane to cover the start. The line movement was strong, moving from -9.5 (that we tipped) to -15.5. While we did not get the result, we picked up where we left off last season, comfortably beating the closing line on our bet selection. Following on from the theme of our podcast, we will provide some colour on how we have come up with our line projection for Collingwood v Adelaide, focusing on the two components of our pricing methodology:
- Initially, we run our statistical team based model, which crunches team based data from a selection of past matches (mainly from 2014) to come up with a team based line projection. We run this model multiple times, tweaking how much weighting each historic game gets. We focus on weighting previous matches between the two teams, and games where teams have a similar player rating to their named line-up for the weekend (if possible). Our team based model’s projection for this game, factoring in home ground advantage was Adelaide by 10 points.
- Next, we run the player based component of the model. We take the weighted average player rating of each team, based on the weightings we gave to each of their historic games that were inputs into the model. We then look at the relative strength of each team for the coming weekend compared to their weighted average strength input into the model, and make a mathematical line adjustment based on any differences.
Player adjustments: Refer to the graph below for point of reference Collingwood adjustment: Collingwood lost one of the best midfielders in the competition in the offseason (Dayne Beams). Furthermore, new recruit Levi Greenwood, star midfielder Steele Sidebottom, and tough nut tagger Brent Macaffer are all out through injury. This leaves some serious holes in their line-up, which is well below the strength it played at in all bar one game in 2014 (where they were flogged by Hawthorn). Therefore, the weighted average of Collingwood’s player ratings input into the model is higher than their squad strength for the coming weekend. This leads to us making an adjustment to our line calculated using our team based statistics model. Adelaide adjustment: Adelaide are playing at a similar strength to what they played at for the back half of the 2014 season (illustrated in the graph below), where their performance notably spiked as they made a run for the top 8. The team based model had greater weighting to these games, and limited weighting to their games in Round 6 and 7 where they were well below full strength. Overall, our weighted average of Adelaide’s player ratings input into the model was about on par with their team this weekend, therefore not requiring an adjustment. Final Line = (Team based model projection) + (Home team adjustment) – (Away team adjustment) = Collingwood +24 Based on our projection, we rate the fair value of Adelaide -13.5 as $1.62. The $1.86 available at Pinnacle for subscribers therefore had an expected ROI of 15.4%, making them a solid value investment. The line has now moved out to Adelaide -16.5 at Pinnacle, however at the improved odds of $1.93 there is still value there, with this bet having an expected ROI of 12.9%. Prediction: Adelaide by 4 goals Bet: Adelaide -16.5 @ $1.934 (Pinnacle) Bonus content: 2014 match-up analysis Round 9, Adelaide Oval. Line: Adelaide +14.5 As you can see in the graph above, Adelaide’s line-up was bolstered before their Thursday night showdown with Collingwood at Adelaide Oval last year. Our model identified this, and while almost being a bet without any player adjustments (given the strong home ground advantage to the Crows), we were a clear bet after adjusting for the Crows increase in player rating. The mug punters were all over Collingwood on game-day, obviously only remembering that Adelaide had lost to Melbourne on the same ground. This game was perfect example of how the public opinion can actually help in creating value in the market, and the importance of not having a one week memory. Round 18, MCG. Line: Collingwood -2.5 Later in the year you can see the two teams met again, this time at the MCG. Adelaide were in good form, and the Pies were playing OK but not to the level of the first half of their season. Our team based model had Adelaide as the better side statistically, however with home ground advantage being with the Pies, we priced this as a 50/50 game. With player rating adjustments however, Adelaide experienced a slight increase, whereas Collingwood experienced a slight reduction, and this was enough to move our price to Adelaide being favourite making them a bet. Get more information on our AFL betting tips.