I propose ROMERBALL.
I thought that myself when I read that article that talked about a Data Scientist(tm)
[Ed.: Bump. This makes sense to me: Michigan should mostly dump special teams once it gets across midfield.]
As Brian highlighted in the UMass round-up, maybe forgoing the punt altogether might not be such a bad decision. He noted my earlier look at the the topic and I wanted to pull it back and revisit and refine some of the work.
I looked at the years 2004-2009 and only looked at the top 20 rated offenses for each year. This study assumes that Michigan’s offense this year will be at a top 20 caliber and provides a broad enough definition of greatness that there is a good sample size. I did not distinguish what type of offense (Texas Tech Air Raid vs Georgia Tech triple option vs spread and shred) was used to get into the top 20. I will detail more assumptions as they are applicable along the way. In place of fourth down conversion percentages I used third down conversion percentage since the data pool is much larger and covers a wider variety of opponent levels. Since the thought process on a third down and fourth downs are roughly the same in most all (for now, anyway) situations, it seems reasonable to use the third down numbers.
Time for a you know what…
Assumptions: Top 20 offense, average defense, average punt game, average field goal kicker.
Based on these assumptions, except for long yardage, the punter should grab a seat once the offense crosses midfield. On your own side of the field the decision still makes sense starting around the 30 for shorter yardage situations and becomes more viable for longer yardage as you cross further down the field. Field goals become practical with 4+ yards to gain and only from about the 5-25 yard lines.
There are two big advantages a potent offense has that make 4th down tries more logical. The first is that they have more to gain by success. With a limited number of drives in a given game, why give them away for free? The second is that they are more likely to make them. Good offenses are more likely to be in better position on fourth down and more likely to make it. Here is a chart of great offenses fourth down conversions compared with all offenses. The right hand column was the one used for the above chart.
|To Go||All Teams||Great Off|
It’s not a huge advantage on any one given down, but Top 20 offenses convert the same opportunities about 2-3 percentage points more often than the average offense. Note: the rate of conversion for great offenses was much higher in the original analysis and is part of the reason the chart isn’t quite as go for it as the original.
But we don’t have an average <blank>
<blank> = Kicker
Let’s start with the kicking game, which is currently 5 points below average on the season and rated third worst in the country after the first three weeks.
Assumptions: Top 20 offense, average defense, average punt game, below average field goal kicker (FG make odds are reduced by 25% everywhere on the field).
The decisions near midfield obviously aren’t changed but now attempting a field goal on 4th and 5-9 from inside the 25 is no longer the most valuable option.
<blank> = Punter
I know it hasn’t been the most Zoltanic of starts for Will Hagerup, but at this point if he can hold onto the snap, there is no point in adjusting him to below average, even if he isn’t an advantage at this point.
<blank> = Defense
This is the one that seems a bit counterintuitive and Brian and I disagree on. I say that the strength or weakness of your defense is irrelevant to your offensive decision on whether or not try a fourth down conversion. My belief that it is irrelevant is based on this chart.
Great defense obviously give up fewer points than bad defenses but the key point is that the difference between a great defense and a bad defense is consistent up and down the field. Giving the opponent a first down at midfield isn’t a guarantee of a touchdown even with a bad defense and isn’t a guarantee that pinning an opponent deep against a great defense will keep the other team off the board. In fact, the gap between the two is about .25 points per first and 10 all the way from the 1 to the 90. If this is true, then the ability of the defense is irrelevant to the offense’s decision to go for it. For that to be the case, there would have to be evidence that the difference between a good defense and a bad defense changes at different points on the field.
So what does all this mean
If Michigan can maintain their feverish offensive pace this year and fail to find an adequate kicker, I think their decision set in all but late game score specific situations should look something like this:
As I noted previously, if you buy into this mentality, it opens up another opportunity, changing your early down play calling. If your four down strategy has changed, so should your down by down playcalling. It may become more viable to risk a wasted down with deep ball knowing that you have an extra, or it might just make sense to keep the ball short in the air and on the ground knowing that over four plays instead of three the likelihood of getting the yardages greatly increases so play to have the shortest possible fourth down attempt if you don’t convert before that.
I propose ROMERBALL.
But I would support a ban on the field goal kicking game.
What about extra points?
I think we have only missed one of those (against UConn). Could be wrong but we seem to be OK in that department. But the way we've been blowing chip shot field goals, I'd rather have Denard take his chances than simply turn the ball over.
if our exptected outcome of a 4th and goal from the 3 is >50% conversion, than we should. i cant say if this is true from the graph since the math is not totally the same, but i'm betting it is. a TD vs field goal is about the same point ratio as 2pt conversion vs PAT
2-pt conversions overall have a success rate of ~45%, so less than half that of XPs (at least 95%, I think). However, Lane Kiffin seems to believe otherwise.
That 45% is the average offense, not top 20 offenses. If you put our offense on the 3 yard line 100 times, how many times would you expect them to get into the endzone? I say it is probably more than 45. Even if it is only 50, that puts you even with your 100 made XPs.
If we run the Jumbo I-formation like they did at ND, we'd get every 2-pt conversion.
And of course, XPs aren't 100%. M, having missed one, is running, lessee... 92.85% (13/14)
I would love to see the NCAA and or the NFL move the extra point to the 1 yard line. I think if the 2 PT conversion was solid option it would make the game much more interesting than kicking a bunch of relatively pointless PATs.
I think the problem with this is you can essentially fall forward every time for 2 points. I don't see how that is more exciting that kicking PATs.
From the 1 the success on third down and goal is about 63%, far from fall forward for two points. This seems like a pretty good ratio to make the risk, uncertainty worth it for coaches but still adding an element of drama. Plus you could still kick late in the game if the score was appropriate.
I figured it would be higher than that. I wonder if that number is affected by good offenses having 3rd and goal from the 1 very often.
is we brought the percentage down last year when we played Illinois
There is one very large counterexample in my mind to the point you're making. I'm not going to bring it up due to bad memories, but just implying.
Is that a pun or an oxymoron?
for all I-A kickers. That actually surprises me, I figured it would be a little lower.
So, the following are chip shots: 38, 39, 40, and 43 yards?
Absolutely, if you have two legs, yes, debatable.
The way it has gone so far, there is no difference between missing the FG and turning the ball over on downs.
Either way, I think it comes down to field position and down and distance. I have all of the confidence in the world for D-Rob, but also we need to keep attempting FG's because I have a feeling that we will need to rely on one of the kickers for a big FG later this season. I just hope he is up for the challenge and can make the kick.
It is for posts like these that I became an MGoBlog member. Outstanding information and analysis! Thanks for the post Mathlete, I really appreciate it.
Great analysis, as always. What if that field goal would give your team either the lead or a 9+ point lead in the fourth quarter? Seems like the risk/reward would come down to the probability of field goal success for that individual play. I wouldn't think that 4th and 8 from inside the 20 would be a 4-down scenario in that situation.
confidence of the kickers, and demoralize the D. I'd never put it in practice (I assume this is an actual proposal and not just a hypothetical). We need 25-34 yard FG's
That said, no doubt RR will go on many 4th-and-somethings inside the opponent's 40. I think he'd rather do that anyway, and now he's got an excuse. I'll roll with that
The assumption is obviously they will start making the easier ones. If they miss 100% of FG's from inside 30 yards, you don't need charts to make the decision.
RR indicated in his presser that he's thinking about this. We'll see him go 4th and 5 from the opponent's 37 yard line, for example. 4th and goal from the 9? He's kicking the FG
it would take the pressure off the already-struggling kickers (and give them more chances to hit XPs), and boost the confidence of the defense by showing that RR believes they can stop the other team anyway. (In fact, it'd be taking a little pressure off the defense; the average spot of the ball after a failed fourth-down conversion would be closer to the opponent's end zone than the spot after a missed FG. If it's punt vs. fourth-down attempt, of course the "advantage" goes to the punt in terms of where the ball is spotted after.) And obviously if the method results in more points overall, it takes pressure off both groups.
The analysis presented here says: Offense is good, Defense is bad, Kickers are bad. You're not going for it because you think the D can hold them if you miss. You're going for it because you think the D is so bad, you may as well let your good O take a shot. This is fine from the 25-40 or so opponent end
If you say we're going for it because you guys are so good you'll hold them even if we miss, that's a different rationale than what's presented here. And evidence to date wouldn't back such an assertion.
When I first read Romer's paper, my football-fan instincts made me cringe at the use of third-down results as a proxy for fourth-down results; I view the defense's response to a 4th down to be far different than for a 3rd down, creating (I thought/assumed) a sizeable difference in outcomes. However, for any fans similarly baffled for why this may be reasonable, I recommend reading his paper. He presents some data - this may be buried within a footnote, I don't recall offhand - which indicate that this assumption is actually quite reasonable, as much as it may intuitively seem to be a poor idea.
Or stated more completely, the "glass half empty" person assigns an expectation of failure to the offense (his team), and therefore emotionally applies more determination to the defense in an irrational justification of "they are trying harder because it's fourth down which is so much better than a stop on third down.
But logically, wouldn't both teams no the fourth down consequences, and thus shouldn't you irrationally place the same "emotion boost" factor to the offense and the defense, i.e. the Offense is trying harder because they know it's fourth down?
so basically, there is no difference between 3rd down and 4th down as long as the yardage to attain 1st down is the same.
Of course the assumption on the playcalling is where things can get haywire. As Mathlete states, if someone adopts going on 4th down as a standard tactic, then the type of play called on 3rd and 1 will start to become different, i.e. riskier, and thus start having a higher failure rate over the entire database.
But conisdering that very few teams have adopted this game time play calling tactic as a standard practice, I think it's very reasonable and logical to assume that the coach is selecting a play that has the greatest chance of achieving a first down, on 3rd down, making it "the final down attempt" sample.
I think the reason you can eliminate the defense from the decision is mostly because you can't change your defense and the failure result, no matter what the decision is, forces the defense onto the field.
Another way to state that is, no matter how the series ends, if it ends with NO POINTS, it is a TURNOVER equal to a fumble or interception that does not result in a score. Consider punting, and the punt return. When you punt, you are turning the ball over, much like a long pass intercepted. The person catching the ball can advance it or can down it where they catch it. The result is the same whether it started as a punt or a pass.
So to me, a punt is just an acceptance of failure, not a positive action to stop failure. You failed to score in that series. Field position is a factor, as the curve shows, and an average punter can give you an advantage for altering field position, but at some point, the amount of field position adjustment is worth less potential advantage than attempting another down.
This is being extremely picky, but it's bothering me, so I'll put it out there. Possibilities from your own 1-10 should go all the way up to the 10 yard level. While you can never have more than 4th and 1 from your opponents 1, you have to have at the very least, 4th and 10 from your own 1.
On a more serious note, what numbers are you using for conversion rates near the goal line? Just general numbers with no relation to the spot on the field or are you using 3rd down conversion rates specific to the yard marker for the spot on the field you are analyzing?
Great work, once again!
On the graph, it bothers me too. Just been too lazy to figure out how to make it look right in Excel. The calculations match the correct yardline/distance combinations, just not the graph.
On the goalline. Good catch, I did not factor in diminished success around the goalline and a quick check shows that conversion rates are about 5-8% lower around the goalline for the same distance. Factoring this in does change things, kicking has a higher expected value with 7+ to go with a bad kicker and 4+ with an average one.
I understand laziness and excel charts.
One last question, how did you arrive at the 25% reduction in kicker effectiveness? I would think that the further out you get, the greater the margin between the average and bad kicker, but then again, maybe that is completely accounted for by the average kicker also missing significantly more as you move beyond chip shot range.
Does the defense chart account for the field position the defense gets for the offense?
Maybe my intuition fails because I expect that a really bad defense will be more field position invariant in its points yielded: if you're really bad you're going to give up a touchdown no matter where the offense starts. If that's not the case then I guess I'm wrong.
There is a slight effect on yards gained changing field position, independent of points allowed, for great vs bad defenses, but the effect is very small and does not change the overall dynamics. Ultimately, it is about the offense. The special teams matter more than the defense, because they have situational value. If a kicker is really consistent, an ability to guarantee 3 from longer range is very valuable, as is a repeated ability to pin an opponent deep without allowing touchbacks. Good defenses are good everywhere and bad defenses are bad everywhere, there is no increase or decrease of relative value (that I have found) depending on where the offense begins a drive.
The chart supports the proposition of field position over good/bad defense. It's about the offense, and if you give it to them inside your 25, they are on average going to get a field goal or TD (4 pts). If they start at the 20 and have 80 yds to go everytime, they only average 1.5 pts, regardless of the good/bad defense.
Thank you for placing numbers to what I've been saying. Your last paragraph is key. Entering a game with the mindset that we WILL go for it on 4th down will greatly change the way other plays are called. 3rd and 10 no longer has to be a passing down. We can run two 5 yard plays (which is about as easy as Shoelace simply breathing).
I support never attempting another FG this season. Seriously.
And, it shouldn't rattle the defense at all. It's not their fault we lack a kicker. The field position is the same whether we go on 4th or miss the FG. The only ones whose confidence may shatter are our kickers...and quite honestly (I'm sure they are great kids who work hard), their confidence is already lacking.
I don't think any games are going to come down to a FG. If they come down to a 3 point differential then we can probably point to other things (poor defense or inept 4th down conversions) as reasons why we would hypothetically lose. In any case, I think the chances with Denard on 4th are MUCH better than expecting one of our kickers to actually make something.
Maybe if you just look at a single example, the defense shouldn't play a big part in the decision but I if you're looking at this being a philosophy for an entire season I would think the quality of your defense would be factored in.
If you punt and pin the opponent deep in their territory, then over the course of a season one would assume that a great defense would be successful more often than not, if not a high percentage of the time, at keeping the opponent pinned and giving your offense really good field position after the ensuing punt. There might not be that large of a difference between a great, good and bad defense keeping the opponent pinned deep in their own territory on one single series, but I think that would guess if one looked at it from the perspective of an entire season.
For example, yes, a great defense would prevent a score on a drive starting deep in the opponent's territory more often than other defenses, but it would also (in general) be better at preventing scores no matter where the drives start. (In other words, it's not like they dampen the curve only between opponents' 20 and goal line; they also dampen it between their own goal line and the 20, etc.) The opponent's expected points would be lower no matter where the starting position was, so turning the ball over on downs would be less costly than it would with a worse defense.
Of course the converse would apply. Given another, um, completely and totally hypothetical example ... a weak defense is more likely to give up points than an average defense. Turning the ball over on downs would be more costly.
But what I think balances that out is the value of possession for those teams. Possession would be, I think, less important for a team with a great defense, because the opponent's average possession would yield fewer points; taking chances doesn't hurt them as much if they fail on fourth down. For a team with a bad defense, possession is more important because the opponents will score more points, so they should feel compelled to go for it more often simply out of need.
The catch is that for this to work, it needs to be your overall philosophy ... which means you would be going for it in situations that might otherwise dictate a punt or a FG. If you don't go for it often enough, then you run the risk of "guessing" wrong (like using a system with 65% accuracy to pick two NFL games per week instead of all 16) and reducing your overall returns.
Going for it also offers the chance to keep their defense on the field longer and rest yours. With a FG attempt or a punt, their defense is getting off the field, barring yackety sax. It's hard to quantify, but definitely a plus.
I did some of my own calculations:
Denard > (Defense + Special Teams + Kickers) * 2
That chart should be all yellow.
that good/bad defense should not affect the 4th down strategy; however, we also have to take into account our defensive play-calling strategy.
With our "bend-don't-break" defense, we are expecting opposing offenses to move up and down the field and on with the caveat that we can hold them to field goals once they get in the red-zone. This being the case, it makes it irrelevant where offenses start on the field against us, they will always be expected to move up and down the field.
With all factors considered; i believe this further promotes the theory that we should be in four down territory starting from just outside of the opposing team's field goal range (~own 30 yard line) to our guaranteed field goal range (~opp 15 yard line)
and last year the Tate punt have been used from around midfield. This keeps the defense guessing, resulting in either an empty backfield or a better chance of converting. I realize there is minimal data, but at what yard line would you call for a QB punt? And do we have a QB punt zone read option? Also, can Denard kick field goals?
I think no FG with denard is actually a viable strategy. It would probably be quite effective.
I think no FG with denard is actually a viable strategy. It would probably be quite effective.
mathlete, can you describe the structure and contents of your database, and how you went about compiling the data? Thanks.
I am far from a database expert but what I have works for what I need it to. My data source is the NCAA official play by plays from their website. The text is copied over from the net into an Excel file that "translates" the text into preset fields. Those fields are then uploaded into Access and I have a host of queries to manipulate the data from there. Each play has about 45 fields and a typical game has 180 or so plays. I have over 880,000 plays right now and will be close to one million by the end of this season.
I think the chart is a great way to consult what your gut is telling you and also based on scenario. Some key factors:
1. Are you at home or on the road? I suspect FG kicking, while highly dicey, would become much dicier on the road. Denard on the other hand seemed just fine in SB.
2. Do you have a solid lead or are you trailing by more than 6? The trailing part is obvious but if you have a solid lead late there's something to be gained by putting your FG kicker out there in a situation with much less pressure to try and build his confidence.
3. Has your defense been good or have the struggled up to this point? I can see looking at this in an abstract sense but if you know your defense has been solid and you have a nice lead there's clear evidence that Lloyd-ing it or playing Tressell-ball seems to be effective.
4. Pace. Michigan obviously likes to push pace but there were times during the UConn game when they would milk the play clock. Doing this over four downs rather than three could be a very effective strategy.
I love the theory and I'd like to see it consulted for times like when Michigan trotted out the FG kicker this past Saturday or on the 2nd FG attempt against Notre Dame. I think everyone pretty much knew neither kick would be successful so having stats that back up your feeling that you should go for it would be epic.
What explains the little blips? Like, why is it optimal to go for it on 4th and 10 from the opposing 15 (I think) but then not a yard closer?