A Different Look At Turnovers: 2011 To Now

Submitted by LSAClassOf2000 on

Turnover analysis is always popular during the football season, but I don’t know that you often see a description of the historic luck that a team has had in turning over the ball under a particular regime, so I thought this might be an interesting route to take.

What I’ve done here is take the range of in-game turnover margins in the entirety of Hoke’s time here to date and compiled some performance and other items as it relates to each of the individual totals rather than the games. In other words, when we have had an in-game turnover margin of “+3”, for example, how did we do? How many times did we actually do that? Those are the sorts of questions we’re going to examine here.

One minor note – I did this for the regular season games only, so if you count only 46 games in these totals and wonder if stuff is missing, that would be the reason. I wanted to concentrate on our past performance against more typical OOC and conference opponents.

I took a couple approaches with the data, but first let me talk about the data.

 In these 46 regular season games to date, we’ve had eight unique outcomes when it comes to turnover margin, ranging from +3 to -4. Both of those extreme performances are rare, the latter being fortunately rare – only twice in each case though. There are a few instance in here where there is an average of a small pool of numbers (I know, grumble grumble), but it is quirk of the size and the things I am attempting to demonstrate, but I say it so you can adjust your conclusions accordingly as we have an instance or two of “n” equals “not enough” perhaps.  It is what it is – technical jargon there.

The first pass at this is a two-in-one sort of deal.  The table below shows each achieved outcome, the win-loss record associated with it, the average scoring margin in those games, and the overall win percentage for each outcome.

 photo TurnoverDiary4_zpscca229b1.png

As you will note, there is some relation to turnover margin and how you perform:

 photo TurnoverDiary1_zps6feed6de.png

What you might be able to see here is that the relationship between turnover margin and the average margin of victory / defeat is pretty clear – the R-squared value is 0.89, in fact. The quirky nature of football (such as winning a game where you are -3 on turnovers – see above) makes the relationship to win percentage, at least in the case of Michigan, present but comparatively mild.

Here’s the distribution of the number of games at each outcome in a convenient histogram:

 photo TurnoverDiary2_zps433eb8e9.png

I have a feeling that a lot of teams would have a fairly similar curve, so while it the case that the most common outcome for Michigan is indeed “-1”, I would think having a majority of your games in the “1” to “-1” range isn’t uncommon at all. That being said, the overall distribution does skew ever so slightly towards the negative for Michigan – of the 46 regular season games since the start of 2011, 21 of them have had use on the short end of turnovers and 10 games were a draw on this metric.

Another look at this involved all the unique outcomes in these games when it came to the physical count of turnovers. Obviously, the best you can do is none – we’ve done that five times. The worst we’ve done, and this game is probably still a good reason to drink, is six turnovers.  The table is below:

TURNOVERS

COUNT (MICH)

COUNT (OPP)

0

5

8

1

20

14

2

4

16

3

10

4

4

6

3

5

0

1

6

1

0

Here’s what that looks like graphically:

 photo TurnoverDiary3_zps6ba48232.png

Curiously bimodal, in our case.  A nice spike at “1” and another, albeit smaller one at “3”. Our opponents have generally stayed in the 1-2 per game range, which is probably something that you can say about many teams, so it likely isn’t a unique result across FBS. The interesting thing is that bimodal distribution in our numbers, as well as this:

TURNOVERS

MICH. AVG. POINTS

OPP. AVG. POINTS

0

34.80

22.13

1

35.10

22.93

2

26.00

18.56

3

28.50

11.75

4

18.50

26.67

5

NO DATA

31.00

6

6.00

NO DATA

Our performance here is interesting too. Very stable between 0 and 1, as you might expect, then it drops by about nine points at 2, increases a little at 3 (because B1G mainly), then behaves more normally.

So, there’s that.

 

Comments

Blue_Blooded92

November 18th, 2014 at 6:00 PM ^

The defensive turnover numbers are pretty impressive, IMO. The past two years have felt as though the defense really isn't always making the biggest plays, or just getting turnovers, and of course they aren't averaging 3 a game. But I was surprised to find that maybe the defense's big play ability was just overshadowed by the offense's propensity to give the ball away.

michelin

November 19th, 2014 at 12:20 PM ^

but games with the same net turnover margin are not all the same.  For example, a factor that could alter the relation between the win pct and the net turnover margin in each game (*) would be the number of turnovers for each individual team (*, *).  You did start to look at that but could go a step further.

To illustrate, two games could have the same net turnover margin (e.g.,  (0) ).  But if both teams turned the ball over zero times (0,0) in one game, the win pct would not be the same as in another game, in which both teams turned the ball over five times (5,5).  In the former case, the win pct should be close to what was predicted by the point spread and prior odds of winning.  A strong team playing against a weak one would have a high likelihood of winning.  But when there are five tunovers for each team, the chances of winning would be more uncertain,  In such cames, the win pct should regress toward 0.50.  

To take an extreme case, suppose both teams turned the ball over on every offensive possession.  Then, the advantage of a strong offense or defense would be largely negated.  The outcome then would be determined largely by the capacity of the defense to play offense and the offense to play defense—e.g., to avoid pick-6s or having fumbles returned for touchdowns.   You would have a lot of 0-0 ties, since nobody could even kick a field goal in multiple overtimes.  My guess is that any chances of actually winning then (by a pick-6 or fumble TD return) would be much closer to a 50-50 coin flip.  They would be less closely related to what was predicted by the point spread and prior odds of winning. 

In more realistic but less extreme cases (e.g., (5,5)), a similar effect should be present, though to a much lesser extent.  That should affect the win pct you report for each net turnover margin (*).  A similar effect should occur if two games have a different margin (e.g., +2 in both games but one is (2,0), the other (6,4)).  So, for games with a high number of total turnovers for both teams, you should have a flatter slope relating win pct to net turnover margin.

To see the effects of total (sum) vs. net (difference) turnovers on win pct, you could plot the  sum vs the difference.  Then, you could denote the win pct on a third dimension (e.g, by the size of each data point).  But to see any meaningful pattern, you would probably need much more data.