Independence on the 4th (Down)

Two years ago I piled onto the idea that coaches don’t maximize on fourth down. Or at least they don’t maximize to scoring the most points. More likely, they minimize the chance of getting fired for making a risky decision.

Within the post I noted that coaches are too conservative and presented an initial treatment to what the decision matrix should look like. I also identified several of the key objections to the “Stop Punting” movement. Over the last two years I have accumulated more data, thought about the topic further and think there is more to add to the conversation. The general conclusion is the same but I have added some new tools that should shed some new light on the subject and bring some power to the people.

A quick review of the main objections:

4th Down stops don’t account for momentum change
I still haven’t found that this has a quantitative impact to anything. Last month I found that teams go for big passing plays more often but that they don’t actually score any more points.

Assumes all offenses and defenses are average
This is a big one. Two years ago I gave this a surface review but will go into more detail below.

Doesn’t account for in-game situations
It’s a valid critique but one that is rarely applicable and easily approximated. With more than 2 possessions left and a competitive game means expected points are directly correlated with win likelihood. A close game late or a blowout will usually point you where you need to go with common sense. In game situations matter, just less than you think they do.

All Men Offenses, Defenses and Kickers are Not Created Equal

This is the big adjustment. Rather than looking at the very best and how their expected value differ from average as I did last time, I made the tool dynamic. I can now look at how each situation changes when you have a dominant offense, or if your defense is a sieve. It can also account for kicker quality. A really good or really bad kicker definitely changes the mindset. Announcers generally frame the decision as “you have to take the three points” even though the odds of success are significantly less than 100%. A great kicker will push the decision closer to that thinking for a quarter of the field. Likewise a terrible kicker takes the field goal out of play for a large portion of the situations.

So to see how different strengths and weaknesses affect the outcomes lets start with the updated baseline chart:

Maximum “go” territory is around the Opponent’s 32 yard line where even on 4th and 10 going for it might be the best play. Once you hit the 20 yard line the field goal is the best option unless you only have one yard to go. This stays true until you get inside the 10, then the opportunity for 3 yards or less becomes more optimal.

So what happens when you get a large variance in teams’ offense and defense. A great example would be the infamous Michigan 2010 team. The offense was as great as the defense and kicking game were terrible. Plugging in extreme values for all three dramatically changes the decision matrix.

Michigan 2010 should have gone for it early and often. Field goals should not have been attempted of 40 yards or more and if the yards to go were 6 or less the offense should have always stayed on the field.

Michigan 2011 was a dramatically different team from 2010. The offense was still good, but not as great as 2010. The defense stopped being a tire fire and the kicking game was much more reliable. I adjusted the offense down a bit and the defense up considerably and moving kicking to average.

The end result is a chart that is somewhere between the baseline and the Michigan 2010. Field goals become the best option when the distance to go is greater but aggressiveness when crossing the 40 is still warranted.

Life, Liberty and the Pursuit of Proper 4th Down Strategy

As part of this work, I have built a public Google Spreadsheet that you at home can use to overanalyze your favorite 4th down situation, complete with dynamic skill ranges.

4th Down Calculator

Each situation adjusts the 4th down conversion chances and upside and downside of any decision. It outputs what the best decision would be and how many expected points you would be leaving on the table with the “wrong” choice.

The offensive and defensive ratings go from +5 to -5 with 0 being average. They are a measure of the difference between the offense and the defense. Michigan’s offense should be a +5 against Minnesota but probably a -2 against Alabama. The rating affects both the odds of conversion and the value of the resulting 1st down if successful. Defense is the same in that it is a measure of the difference between your defense and the opponent offense. Adjusting the defensive metric affects the value of a resulting possession change whether by missed FG, punt or missed fourth down conversion.

I hope you enjoy looking at this and I included some special Easter Eggs for the curious.