Wednesday, December 20, 2017

AFL roster analysis



[Originally published in The Roar]

      Now that the trading period and draft is over, we can start to get a feel for what the 2018 rosters will look like for each of the 18 AFL teams looking to play through to the end of September this coming year. 

     If you've read my work here before, you'll remember that I'm a maths geek and like to spend my free time crunching numbers looking for trends and predicting future performance. My track record, using my "ELO-Following Football" rating system for teams and players (and now for male and female!) has proven to be more accurate than the odds-makers and the vast majority of pundits out there. (Not by much, mind you! But more than a trivial amount!) I'm not comfortable saying "use these forecasts for gambling purposes", but you do you, y'know?

     So, trying to project what each club will have to work with next year will give us a head start on projecting what they'll accomplish in league in the fall and winter. There are two numbers to share with you in pursuit of this goal.

     One is the "Following Football" rating from last September, the year-end resultant of the on-field production using the ELO method (a zero-sum calculation where you compare expectation to result and add to the rating of the team which outperformed expectation the same amount you subtract from the rating of their opponent). As we do every season, we normalized those numbers towards the mean to address the normal tendencies during the season to spread apart; in the AFL, we find that a 20% reduction figure is about right.

     The other is new to readers of The Roar: we've taken the top 29 players on each team's projected roster (nine forwards, nine midfielders, nine backs, and two ruckman) and assigned them a point value based on their projected points for the coming season, using the previous three seasons where applicable. We've been very conservative with changes - if they were, say, the one-hundredth rated player overall last season, then (barring injury, trade, moving positions or other mitigating factors) they're probably valued as about that right now. Young players will probably improve a bit; old players will probably fade a bit. You get the idea. (Incidentally, this would be easy for you to do with fantasy values - although those values aren't quite as functional for this purpose as the ELO numbers are, because they're designed for a slightly different purpose. But I won't swear they're not as good; I've just found that this seems to work better.)

     Why 29 players, when they only field 22? By the time they reach the bye, most teams have used about that many bodies on the field. If they're fortunate, they won't have to dig any deeper - if they're GWS last year, they'll be hip deep in unused guernseys. Besides that, beyond those top 29 it becomes tougher to forecast who will come out of the feeder league bushes and show improvement enough to be given a shot. 

     So, without ado, here are those numbers (written as [total roster projected points, current team rating]):

Adelaide (3409, 74.0)
Geelong (3250, 63.3)
GWS (3143, 60.3)
Melbourne (3126, 50.1)
Port Adelaide (3124, 62.2)
Sydney (3046, 75.0)
Richmond (2959, 77.6)
Essendon (2885, 46.8)
Hawthorn (2680, 50.5)
Fremantle (2621, 24.5)
West Coast (2615, 50.3)
Collingwood (2598, 51.4)
Brisbane (2546, 27.4)
St. Kilda (2408, 50.1)
Western BD (2108, 45.7)
No. Melbourne (2062, 38.9)
Carlton (2002, 35.2)
Gold Coast (2002, 16.2)

     Some things stand out, and while it may belabor the obvious in some cases, we'll point them out anyway.

     Teams that seem to have stronger rosters than their record or rating would tell us from last year? The most prominent teams are Melbourne, up in fourth on the roster point list when they didn't make finals last year, and Fremantle, which was free-falling to the bottom at the end of the year. Their roster number indicates a .500 season or so, resting 11th overall and just ahead of the co-tenants, West Coast. Brisbane's off the bottom of the table as well, but that shouldn't be a surprise to anyone watching this young team last season!

     Which teams are surprisingly thin on talent? The names in 15th and 16th are notable: St. Kilda is at the bottom end of the middle pack, at 2408 (the average here turns out to be right around 2700, for comparison). But the Doggies look to be in trouble this year, having only the same amount of talent as the three teams deemed to have the "least talented roster" by these numbers. the Roos and the Blues, with Dew's Crews right there too. (Too's.)

     Is Western really that strapped for meritorious players? Well, with the Bont not having pulled into that highest echelon (yet) as many expected, the culling of a few veteran players, and some weaknesses disguised by a joy-filled run to the flag in 2016 that the 2017 exposed, the answer is yes. Here's the list of the five highest valued players on their list (according to our numbers) in alphabetical order: Bontempelli, Dalhaus, Hunter, Johannisen, and Macrae. All good players - but how does that stack up against almost any random AFL team? You do the comparison.  

     To fill to the 29th player, we have to include back-and-forth players like Josh Dunkley, Josh Schache, Lukas Webb, and rookie draft pick Aaron Naughton, who may be wonderful but isn't likely to be their number one option this early. While most teams have this kind of issue at the bottom (else why are those players not starting?), it speaks to the fact that the Bulldogs' roster doesn't have the kind of strength at either end that strikes fear in the hearts of other teams. 

     It was also surprising to see our two highest rated teams, Sydney and Richmond, in sixth and seventh in terms of overall roster strength. Neither team should be overly concerned about that unless there's a tidal wave of injuries that overwhelms either of them this season: doing a quick simulation that combines the current team ratings (for round one) and the roster projected team point numbers (affecting each team's rating gradually up to the bye), Sydney is still one of three teams projected to reach round 15 at 12-1 (the others are Adelaide and Geelong), and Richmond should be somewhere near 10-3 at that point as well. (Those projections assume form holds in every game, which 1/3 of the time it doesn't in the AFL! We used to include that in our forecasts, but discovered it's fruitless to be guessing when fate will blow on the dice!)

     Those projections, by the way, don't reveal anything interesting that the two numbers above don't already show. Adelaide has a great roster number and a great rating, so guess what? They're likely to win most of their games! Gold Coast has just the opposite? Guess what? It's hard to find wins for them on this schedule - although I have faith that Stewart Dew can pull them up at least a little bit.

     Which brings us to our most important intangible: coaching. What effect will Dew have on the Suns? Will an invigorated Nathan Buckley show more flair with the Magpies? In general, what effect does a year make on anything related to a team? I'm convinced that the biggest difference with Richmond in 2017, especially late in the season, was not Prestia or any other new person involved, but rather just the year of growth and experience and "settling in together" of the major players for the Tigers - a year of maturation for Dustin Martin into the prohibitive favorite and winner of the Brownlow, the coordination of the front line and the back line both with time and experience together, and so forth. I'll lay odds they didn't realize what they had until they started to win some games they didn't expect to win!

      So all of this number crunching is much ado about nothing? 

      Not really. It gives us an idea what we're supposed to be looking for this season - who might have sudden surges from their farm system mid-season. It might tell us who's working with duct tape and bailing wire to hold the team together until they can bring some youth into the fight down the road. In Brisbane's case, and perhaps Adelaide's as well, it confirms what we've been thinking about their growth as up-and-coming teams. And, frankly, it's just fun to play with. Why else would we invest so much time in "fantasy football" and tipping contests when there's no serious merit to either? Because we like it! It gives us some tangible way to "be involved" in footy, even when it's a full level removed from the "real thing".

      In a sense, this is our "cos-play". If we have Paddy Dangerfield on our fantasy team, we can watch the game from his perspective, living and figuratively dying with his every possession. If we've clicked the box next to Collingwood's name, we become invested in their performance that week in a way that we wouldn't have been before - even without money riding on the outcome, our pride alone will keep us attached. 

     So take it seriously, but no more seriously than you take the game itself. And in the end, footy IS just a game.

     [NOTE: the author was later taken out, placed in a potato sack and beaten with cricket bats for his blasphemy.]

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