Showing posts with label analytics. Show all posts
Showing posts with label analytics. Show all posts

Friday, April 12, 2013

Which Teams Overachieved and Which Teams Underachieved in 2012?

Tonight, while working putting together the final validation of the 2013 FBS Prediction Model, my analysis of the results highlighted some very interesting, and kind of disconcerting, things about Nebraska's 2012 season.

The model simulates every FBS game for the entire season.  

As validation, I used the methodology to simulate the 2012 season and prepared a comparison between between the model results and the real game results.  

This first chart shows some of those results of the predicted versus actual wins. 

A positive number of the vertical axis means the model predicted more wins than a team achieved.  Likewise, the negative numbers mean the model predicted fewer wins than the team achieved.

The average delta between the predicted win total and the actual win total is 1.15 games per team. 

21% of teams were predicted correctly.  20% were under-predicted by one win, and 29% were over-predicted by one win.  The model predicted more than 70% of seasons accurately to within one win.

The model under-predicted 12% of season by two wins and 5% by three wins.  It over-predicted 7% over season by two wins and 6% of season by three wins.

Can you guess which team was the most over-achieving?  

You betcha. Dear Old NU.  

The model predicted 6.91 wins but the Huskers finished with 10 wins, for a delta of -3.09 wins.  

While some may be inclined to see this as a positive, and it's certainly better than winning three fewer games than the model anticipated, the fact remains that Nebraska's scoring offense and scoring defense (the basis of the model) should have resulted in a 7-win season...not a 10-win season.

Remember the amazing streak of 4th quarter heroics in the Wisconsin, Northwestern, and Michigan State, and Penn State games?  Remember how Denard Robinson left the game before halftime?   

Sometimes, it's better to be lucky than good.

Interestingly, Ohio State is the #2 most overachieving team, with a predicted win total of 9.12.  Had they played in the Big Ten Championship Game or a bowl game, they would almost certainly have been the most overachieving team by a large margin.

The Top-10 overachievers and Bottom-10 underachievers are:


I put a table with the full results of the model at the end of this post.

Finally, the model provides some insight into the consistency of a team's on-field performance.  The standard deviation of the predicted wins can be used as a proxy for a team's consistency.

So, can you guess which team had the largest standard deviation in the model results, and by proxy, was the least consistent and predictable?  

Yup, Dear Old NU.  Again.

Now, guess which team had the lowest standard deviation in model results.  

Hint:  they won the National Championship.

I'll let my readers draw their own conclusions about this one.

By the way, I'm now a writer over at Football Study Hall.  Stop by and check it out.  I'll be writing about more than just the Huskers over there.

GBR!
@HuskerMath







RankTeamConfPred. WinsActual WinsDelta (rnd)Pred. DeltaAbs( Pred Delta)
1Northern IllinoisMAC13.11211.11.1
2AlabamaSEC12.7130-0.30.3
3Florida StateACC12.51210.50.5
4Utah StateWAC11.21100.20.2
5OregonPac-1211.012-1-1.01.0
6UCFC-USA11.01011.01.0
7GeorgiaSEC10.912-1-1.11.1
8Boise StateMWC10.8110-0.20.2
9Arizona StatePac-1210.7832.72.7
10CincinnatiBig East10.61010.60.6
11TulsaC-USA10.5110-0.50.5
12BYUInd10.5822.52.5
13Texas A&MSEC10.411-1-0.60.6
14Kansas StateBig 129.911-1-1.11.1
15North CarolinaACC9.8821.81.8
16RutgersBig East9.8910.80.8
17ClemsonACC9.811-1-1.21.2
18Oklahoma StateBig 129.8821.81.8
19Bowling GreenMAC9.7821.71.7
20OhioMAC9.7910.70.7
21VanderbiltSEC9.7910.70.7
22San Jose StateWAC9.611-1-1.41.4
23Fresno StateMWC9.6910.60.6
24StanfordPac-129.612-2-2.42.4
25Kent StateMAC9.511-1-1.51.5
26WisconsinBig Ten9.4811.41.4
27South CarolinaSEC9.211-2-1.81.8
28Notre DameInd9.212-3-2.82.8
29Arkansas StateSun Belt9.210-1-0.80.8
30Ohio StateBig Ten9.112-3-2.92.9
31San Diego StateMWC9.1900.10.1
32Penn StateBig Ten8.8810.80.8
33FloridaSEC8.711-2-2.32.3
34LSUSEC8.710-1-1.31.3
35Oregon StatePac-128.790-0.30.3
36Louisiana-LafayetteSun Belt8.690-0.40.4
37NorthwesternBig Ten8.610-1-1.41.4
38OklahomaBig 128.510-2-1.51.5
39MichiganBig Ten8.3800.30.3
40UCLAPac-128.29-1-0.80.8
41Louisiana-MonroeSun Belt8.2800.20.2
42PittsburghBig East8.1622.12.1
43Western KentuckySun Belt8.1711.11.1
44LouisvilleBig East8.111-3-2.92.9
45Mississippi StateSEC8.1800.10.1
46RiceC-USA7.9710.90.9
47TCUBig 127.8710.80.8
48SMUC-USA7.8710.80.8
49Louisiana TechWAC7.79-1-1.31.3
50USCPac-127.7710.70.7
51NevadaMWC7.6710.60.6
52Michigan StateBig Ten7.5710.50.5
53SyracuseBig East7.48-1-0.60.6
54North Carolina StateACC7.4700.40.4
55ToledoMAC7.29-2-1.81.8
56East CarolinaC-USA7.28-1-0.80.8
57NavyInd7.28-1-0.80.8
58Air ForceMWC7.2611.21.2
59Georgia TechACC7.1700.10.1
60TexasBig 127.19-2-1.91.9
61Texas TechBig 127.08-1-1.01.0
62NebraskaBig Ten6.910-3-3.13.1
63Western MichiganMAC6.8432.82.8
64UTSAWAC6.68-1-1.41.4
65Central MichiganMAC6.670-0.40.4
66New MexicoMWC6.5432.52.5
67Virginia TechACC6.47-1-0.60.6
68ConnecticutBig East6.4511.41.4
69Iowa StateBig 126.4600.40.4
70WashingtonPac-126.37-1-0.70.7
71Middle TennesseeSun Belt6.38-2-1.71.7
72Ball StateMAC6.39-3-2.72.7
73BaylorBig 126.28-2-1.81.8
74MississippiSEC6.27-1-0.80.8
75MinnesotaBig Ten6.2600.20.2
76TroySun Belt6.1511.11.1
77UtahPac-126.1511.11.1
78MemphisC-USA5.9421.91.9
79IowaBig Ten5.6421.61.6
80Miami (Florida)ACC5.47-2-1.61.6
81West VirginiaBig 125.37-2-1.71.7
82PurdueBig Ten5.26-1-0.80.8
83ArizonaPac-125.28-3-2.82.8
84Texas StateWAC5.1411.11.1
85HoustonC-USA5.1500.10.1
86WyomingMWC4.9410.90.9
87South AlabamaSun Belt4.8232.82.8
88MarshallC-USA4.850-0.20.2
89UNLVMWC4.8232.82.8
90VirginiaACC4.8410.80.8
91MarylandACC4.8410.80.8
92North TexasSun Belt4.7410.70.7
93Colorado StateMWC4.7410.70.7
94BuffaloMAC4.6410.60.6
95IndianaBig Ten4.5400.50.5
96TennesseeSEC4.45-1-0.60.6
97UTEPC-USA4.4311.41.4
98Florida InternationalSun Belt4.3311.31.3
99UABC-USA4.3311.31.3
100DukeACC4.26-2-1.81.8
101AkronMAC4.0133.03.0
102ArmyInd4.0222.02.0
103South FloridaBig East3.9310.90.9
104TempleBig East3.940-0.10.1
105Boston CollegeACC3.8221.81.8
106Florida AtlanticSun Belt3.8310.80.8
107MissouriSEC3.55-2-1.51.5
108ArkansasSEC3.54-1-0.50.5
109AuburnSEC3.4300.40.4
110Wake ForestACC3.35-2-1.71.7
111Miami (Ohio)MAC3.34-1-0.80.8
112Washington StatePac-123.1300.10.1
113CaliforniaPac-122.830-0.20.2
114HawaiiMWC2.730-0.30.3
115KentuckySEC2.5210.50.5
116New Mexico StateWAC2.4111.41.4
117IllinoisBig Ten2.4200.40.4
118Eastern MichiganMAC2.3200.30.3
119TulaneC-USA1.820-0.20.2
120KansasBig 121.8110.80.8
121Southern MississippiC-USA1.7021.71.7
122IdahoWAC1.3100.30.3
123ColoradoPac-120.910-0.10.1

Saturday, March 9, 2013

Placing Fumbles in Context (Part 2)

Continuing my breakdown of fumbles, Part 2 looks at fumbles by distance to go, player position, and quarter.


Distance (to go)


Looking at the entire football field, the breakdown of fumbles by down and distance looks like this (fumbles on kickoffs and punts are excluded):

1st and 10 accounts for the overwhelming majority of fumbles, but it accounts for the lion's share of the down-distance pairings during a game, so there's nothing particularly surprising in that.  

For distances of 10 or greater, 12% of fumbles occur on 2nd down, 5% on 3rd down, and less than 1% on 4th down.  
For distances of fewer than 10 yards, 2nd down accounts for 21%, 3rd down accounts for 17%, and 4th down accounts for 3% of fumbles.

Because the fumble percentages correspond closely to the actual play distribution by distance to go in a football game I'm led to conclude that distance to go is not a significant contributing factor to the probability of a fumble occurring on a play.



Player Position





Across the FBS, QB's accounted for about 50% of fumbles in the opponent red zone. The percentage of QB fumbles decreased steadily as the team approached the end zone. Running backs' percentage of fumbles increased steadily as a team approached the end zone. WRs were most likely to fumble in the middle of the field. Interestingly, DBs accounted for a not-insignificant number of fumbles. I suppose this is following interceptions or fumble recoveries.




When I look at this chart, absolutely nothing important jumps out at me. While there is some variation in frequency of fumbles between quarters, there's no reason to think that it is due to any reason other than chance.  


Conclusion

And this concludes my breakdown of fumbles.  If there's a useful takeaway from Parts 1 and 2, I think it is the improbable frequency of fumbles on punt returns.  


Thursday, March 7, 2013

What can and can't sports analytics do?

Andrew Sharp at SBNation has a great article called Paralysis by Analysis in which he details his visit, as a confessed analytics skeptic, to the the MIT Sloan Sports Analytics Conference.  This conference, to guys like me, is like making the Hajj to Mecca for the world's muslims.  It has to be done, but everybody knows its damn expensive, so Allah (or in my case, Nate Silver) understands if it doesn't work out.

It got me thinking, along with a negative comment left by a reader this week, that some folks are misunderstanding what I'm trying to do, and what sports data and statistics analysis can do and can't do.

What can't sports analytics do?  It can't predict what's going to happen on the next play, series, inning, snap, or whatever.  It can't explain WHY something happened. And it can't take the place of a coach's experience.

What can sports analytics do?  It can provide insights into aspects of the game that are not readily apparent to someone watching, coaching, or browsing the box scores. It can serve as an early warning to coaches and managers about potential problem areas and trends before they manifest themselves in the box score (at which time it's probably too late).  And it can function as a way to evaluate players and coaches in a (mostly) objective manner.

The negative comment I mentioned above said this:  

After all of that it means really nothing...You still cannot prevent these kind of mistakes, and you surely will never be able to look at these graphs and charts, and decide before the next play "the fumbles a coming, better tell so and so to hang on to the ball".....Pretty much a big ole waste of time.....
The comment was directed at the first part of a two-part piece on fumbles that I wrote earlier this week.  I appreciate the commenter's feedback, but I think he's missing the point.  Or maybe I failed to help him understand the point.

That piece wasn't about saying "this play will result in a fumble".  It was about digging into the limited data available to identify relationships between separate events that might be exploitable.  What I found was that fumbles on punt returns occur far more often than they should if they happened at the same frequency as punts.  They don't, and that is an exploitable nugget of information.  A coach could take that to heart and realize that he needs to place more emphasis (read: time, practice, and coaching) into the act of catching and returning a punt.

Whether the analytics are the low budget work I'm doing or the amazing technology gathering and analysis that companies who went to the Sloan conference are engaging in; we are trying to do the same thing...uncover the hidden information in the game so coaches and players and make better informed decision.

GBR!

Paul