Analysis Team ratings

[grumbleguts]

In the headf**ked thread, I mentioned I had a system based on the mathematics dominance matrices to rate teams for tipping.

In calibrating the system it almost correctly (one error in the overall ladder) determined the final ladder after 7 rounds for the 1978 season.

Here is a little video on how it works (although my matrix is a lot more complicated - it dooesn't simply use wins and losses it uses scores and it is an 18 team competition.


So I decided to rate teams after each round in the season and see how they panned out at the end of the season. (Now it is purely mathematical so it doesn't take into account injuries, home vs away {although this could be accounted for with sufficient back data} or anything.)

but thought I'd share.
By round 16 last season it correctly determined a Hawthorn West Coast GF with Hawthorn winning easily (despite 5 losses at that point) and despite Freo being two wins clear on top.

The system takes into account how many good teams (highly ranked teams) you play and rates the win accordingly. So for example in a three team comp with only two matches played Let's say A beats B and B beats C
The matrix would look like this:
...A B C
A 0 1 0
B 0 0 1
C 0 0 0

(A has one win against B and B has one win against C ie the rows are results the columns are the reverse (losses) ) Applying dominance matrix maths to this you get


...A B C
A 0 0 1
B 0 0 0
C 0 0 0

Thus the maths predicts A will beat C without A ever playing C. It gets much more complicated very quickly, but that is the gist.

So at round four this season the ratings looked like this:
4 rounds
Sydney Swans 31.05735
Hawthorn 27.4198
GWS Giants 26.87024
Western Bulldogs 24.59706
Adelaide Crows 23.85835
Geelong Cats 21.92452
Brisbane Lions 18.48172
West Coast Eagles 18.42143
North Melbourne 17.56654
Gold Coast Suns 16.97817
Melbourne 16.59622
Port Adelaide 15.8158
Fremantle 15.59715
St Kilda 14.76927
Essendon 14.06255
Richmond 11.84983
Carlton 11.68361
Collingwood 11.40139

 

[grumbleguts]

After 5 round the rating looks like this:

Round 5
Sydney Swans 53.94376
Hawthorn 38.51343
Western Bulldogs 37.82005
Adelaide Crows 34.67217
GWS Giants 32.89826
North Melbourne 32.5651
West Coast Eagles 27.6786
Geelong Cats 26.80001
Gold Coast Suns 26.45537
Brisbane Lions 25.63915
Melbourne 23.03908
St Kilda 19.44125
Port Adelaide 19.04645
Fremantle 18.27934
Essendon 17.31355
Richmond 15.89972
Carlton 14.25511
Collingwood 14.22675

 

[grumbleguts]

The 6th round produced some big results: (we got thrashed by GWS, Geelong thrashed Gold Coast, and Swans just got by against brisbane - hence brisbane large growth)
Round 6
Sydney Swans 69.25843
Geelong Cats 58.6896
GWS Giants 54.00776
Western Bulldogs 53.3439
Hawthorn 53.18987
North Melbourne 51.89061
Adelaide Crows 47.41049
West Coast Eagles 43.0538
Brisbane Lions 39.30368
Gold Coast Suns 36.85917
Port Adelaide 31.7781
Melbourne 31.60407
St Kilda 31.09813
Fremantle 26.08493
Essendon 24.85103
Richmond 23.99977
Carlton 21.15056
Collingwood 21.03954

 

[grumbleguts]

Round 7 we beat richmond, GWS had a fright against Freo. Note that although North is undefeated at this stage they are still ranked only 7th, and freo despite being winless is rated 5th from the bottom:


Round 7
Sydney Swans 90.65542
Geelong Cats 79.16764
Western Bulldogs 72.60198
GWS Giants 71.72997
Adelaide Crows 68.8757
Hawthorn 67.01294
North Melbourne 65.75151
West Coast Eagles 58.74044
Melbourne 50.44589
Brisbane Lions 48.76403
Gold Coast Suns 47.47007
Port Adelaide 47.02958
St Kilda 42.99759
Fremantle 36.47205
Essendon 34.99585
Richmond 33.63923
Carlton 30.99212
Collingwood 29.98073

 

[OzJohnnie]

Thanks, gg.

 

[OzJohnnie]

Hmm... I guess I shouldn't complain about the bias of a proven formula... But this is crap!

Actually, I guess is says exactly what we already know (but wilfully deny and wistfully ignore). The Hawks have fallen back to the middle of the top pack. And the top pack was very tight after round 7, except for Sydney.

I'm very interested to see what it looks like after this round. Has GWS broken free and Sydney fallen back to the pack?

I'll also be watching it closely for what it says after rounds 15 and 16. If we account for Port and Sydney then I guess we'll be at the top and in a good spot to challenge again. If not we'll need a little magic to help out.

 

[grumbleguts]

Round 8
Round 8
Sydney Swans 119.6881
Geelong Cats 107.6367
GWS Giants 101.997
West Coast Eagles 99.37216
Adelaide Crows 97.40339
Western Bulldogs 93.92509
Hawthorn 91.17104
North Melbourne 78.65109
Melbourne 68.55898
Port Adelaide 60.50278
Brisbane Lions 59.42931
Gold Coast Suns 59.00832
Richmond 54.72895
St Kilda 53.27892
Fremantle 50.14269
Carlton 47.24503
Collingwood 46.8957
Essendon 46.60794

 

[grumbleguts]

Round 9
Sydney Swans 135.8761
GWS Giants 129.5763
Geelong Cats 127.5612
Adelaide Crows 126.2597
West Coast Eagles 123.8679
Western Bulldogs 116.0758
Hawthorn 112.8825
North Melbourne 106.9513
Melbourne 88.85062
Port Adelaide 84.88779
Gold Coast Suns 73.90761
Collingwood 72.69306
Richmond 72.16456
Brisbane Lions 71.02502
Essendon 65.24481
St Kilda 64.22038
Fremantle 60.74817
Carlton 59.50057

 

[grumbleguts]

Round 10
Sydney Swans 168.8895
West Coast Eagles 162.8067
Adelaide Crows 156.5695
GWS Giants 152.7987
Western Bulldogs 148.4605
Geelong Cats 147.37
Hawthorn 136.8356
North Melbourne 129.7837
Port Adelaide 115.1036
Melbourne 104.3041
Collingwood 92.39597
Richmond 91.61033
Gold Coast Suns 87.74461
St Kilda 86.11572
Carlton 85.99311
Brisbane Lions 85.14138
Essendon 78.32575
Fremantle 67.21816

 

[grumbleguts]

Round 11
Sydney Swans 203.5634
Adelaide Crows 198.9397
West Coast Eagles 192.1164
Western Bulldogs 188.6597
North Melbourne 169.9623
GWS Giants 167.4016
Hawthorn 166.9358
Geelong Cats 161.7269
Port Adelaide 147.1105
Melbourne 121.5282
Richmond 112.7875
Gold Coast Suns 109.0319
Collingwood 105.3127
Carlton 103.7676
St Kilda 103.0955
Brisbane Lions 99.23548
Fremantle 94.67513
Essendon 88.63176

And essendon in their rightful place.

 

[grumbleguts]

Round 12
Adelaide Crows 244.3795
West Coast Eagles 224.4786
Western Bulldogs 223.2861
Sydney Swans 213.2976
Hawthorn 207.5258
Geelong Cats 197.7811
North Melbourne 196.2249
GWS Giants 190.5325
Port Adelaide 172.2853
Richmond 134.821
Melbourne 132.0903
Gold Coast Suns 126.0191
St Kilda 123.2736
Carlton 120.9204
Fremantle 118.9697
Collingwood 111.7975
Brisbane Lions 109.9343
Essendon 100.1451

 

[grumbleguts]

For the bye rounds I made the bye teams play themselves and draw (if that makes sense) to quote ross lyon.
Round 13
Adelaide Crows 274.6095
Sydney Swans 259.1812
Geelong Cats 251.4471
Western Bulldogs 244.6817
West Coast Eagles 238.9019
Hawthorn 238.6403
North Melbourne 225.3501
GWS Giants 216.9916
Port Adelaide 188.3766
Carlton 147.2471
Gold Coast Suns 146.8028
Melbourne 146.3306
Richmond 145.7533
Fremantle 145.5688
St Kilda 140.7662
Essendon 120.0372
Collingwood 118.4346
Brisbane Lions 118.1894

 

[grumbleguts]

Round 14
Adelaide Crows 302.476
Sydney Swans 300.829
Western Bulldogs 281.285
Geelong Cats 279.011
West Coast Eagles 278.8876
Hawthorn 271.6646
GWS Giants 254.3431
North Melbourne 236.2842
Port Adelaide 223.5804
Melbourne 172.6088
St Kilda 172.166
Gold Coast Suns 169.1923
Richmond 167.6796
Fremantle 161.5473
Carlton 160.9646
Collingwood 156.061
Essendon 138.1212
Brisbane Lions 133.1073

 

[Dewnior]

Round 14
Adelaide Crows 302.476
Sydney Swans 300.829
Western Bulldogs 281.285
Geelong Cats 279.011
West Coast Eagles 278.8876
Hawthorn 271.6646
GWS Giants 254.3431
North Melbourne 236.2842
Port Adelaide 223.5804
Melbourne 172.6088
St Kilda 172.166
Gold Coast Suns 169.1923
Richmond 167.6796
Fremantle 161.5473
Carlton 160.9646
Collingwood 156.061
Essendon 138.1212
Brisbane Lions 133.1073

Interestingly, the model has West Coast above us yet with 3 less wins.

 

[grumbleguts]

Interestingly, the model has West Coast above us yet with 3 less wins.

To be fair three of our wins were practically draws.

 

[S Lawrence]

Round 14
Adelaide Crows 302.476
Sydney Swans 300.829
Western Bulldogs 281.285
Geelong Cats 279.011
West Coast Eagles 278.8876
Hawthorn 271.6646
GWS Giants 254.3431
North Melbourne 236.2842
Port Adelaide 223.5804
Melbourne 172.6088
St Kilda 172.166
Gold Coast Suns 169.1923
Richmond 167.6796
Fremantle 161.5473
Carlton 160.9646
Collingwood 156.061
Essendon 138.1212
Brisbane Lions 133.1073

 

[Gralin]

To be fair three of our wins were practically draws.

The most important thing about those wins was they allow Clarko and co some breathing room.

They might not make us look good in a lot of ways, they may even prove at the end of the year to be exactly what a lot of people are hoping - proof we are not good enough.

What they have done is allow us to rest/manage players with niggles, take the long view with Hodge's knee in particular and keep getting games into the kids and use time in games to tinker.

I'm hopeful as the year progresses that we will make progress up in the ratings and stay in the top 4, hopefully top 2 and be primed with as fit a list as possible for finals

 

[grumbleguts]

It also hasn't taken into account the lack of Hodge or roughead for the bulk of the year. For the personnel on the field it's not a bad representation of where we've been.

 

[Argy]

That's pretty similar to the Squiggle, except your system has the doggies above us and the squiggle doesn't.

 

[Gralin]

That's pretty similar to the Squiggle, except your system has the doggies above us and the squiggle doesn't.

Squiggle does give some rating to homw ground though and I'd expect isn't the same algorithm
Also gives weight to last year

 

[grumbleguts]

That's pretty similar to the Squiggle, except your system has the doggies above us and the squiggle doesn't.

It may be back in sync after the bye.
My system unfairly weights teams that have played more games, as the points are cumulative. So until the byes are finished, teams that have had the bye and are a game behind have been allotted a draw (point ratio of 1) against themselves.

 

[Dewnior]

It may be back in sync after the bye.
My system unfairly weights teams that have played more games, as the points are cumulative. So until the byes are finished, teams that have had the bye and are a game behind have been allotted a draw (point ratio of 1) against themselves.

Aaaahhh, so after tomorrow night your model will have Weagles in the top 3 but they'll be at best 7th on the ladder.

 

[grumbleguts]

Squiggle does give some rating to homw ground though and I'd expect isn't the same algorithm
Also gives weight to last year

This is a good point. I did a quick check of average home vs away score to make the adjustment but haven't incorporated it yet. (quite a bit of work.) But the 1978 season, I assigned as a maths assignment giving the data up to round 7 and calling the teams the meerkats, the gorillas etc. (Hawthorn were meerkats because they are the coolest animal in the african system.) Then gave them the final ladder after 22 rounds after they had gotten some system. Then they had to refine their system and write a report. That way I had 27 really brilliant kids refining an algorithm I had already put together in crude form. (The numbers here are the crude algorithm I started with though - don't want to put anything out in the real world that doesn't acknowledge some of the other contributors.)

 

[grumbleguts]

Aaaahhh, so after tomorrow night your model will have Weagles in the top 3 but they'll be at best 7th on the ladder.

Not necessarily, if they beat essendon by a smaller ratio than others below them, they'll drop. For example in round 8 we dropped in rating after beating freo 116 75, because freo were winless and Stkilda got smashed by west coast, 132 29 (remember its ratio not margin to take weather out of the equation) That ratio (4.55) is the largest of the season. Now we beat st kilda by only 3 points, so although we won that round, the algorithm drops us in esteem because be failed to smash a team that just lost a whole lot of respect.

 

[grumbleguts]

Here's a more refined set of numbers giving less weight to calculations further out. eg when team A beats team B and team B beats team C If team C beats team G them team A rises slightly (because it is better than B C and G even though there are several layers between A and C (I made that rise weighted less - I also dampened the numbers a bit so they aren't so high.

This seems to show that it is VERY tight at the top. 6 teams all very similar.

(This will take a few seasons to perfect with an 18 team competition but little by little it will hopefully become a pretty decent predictor of final ladder positions early in the piece.

*It sh ould be noted that teams that are playing this week have a draw against their name against themselves. Expect essendon to drop after tonight.

Geelong Cats 81.8624
Sydney Swans 81.22379
Adelaide Crows 81.11381
Western Bulldogs 75.82205
West Coast Eagles 75.63839
Hawthorn 74.37114
GWS Giants 71.29577
North Melbourne 64.26797
Port Adelaide 59.90633
Melbourne 49.97803
St Kilda 48.15192
Richmond 47.3928
Fremantle 46.67537
Gold Coast Suns 46.00623
Collingwood 45.83444
Carlton 43.51785
Essendon 38.05466
Brisbane Lions 35.34902