The five factors: College football's most important stats

Thomas Campbell-USA TODAY Sports

College football comes down to five basic things, four of which you can control. (UPDATED at the bottom.)

The most revolutionary ideas are sometimes the simplest. Almost 10 years ago, Dean Oliver introduced what he called "Roboscout" by discussing the four factors for winning basketball games. Oliver has come up with a lot of interesting measures through the years, both before and during his life as the head of ESPN's sports analytics team, but his most lasting idea wasn't really a measure at all.

It was the basketball version of the "You throw the ball, you hit the ball, you catch the ball" quote from Bull Durham: you hold onto the ball, you shoot the ball, you grab the misses, you draw contact. But Oliver's four factors concept has become commonplace. They are the basis for Ken Pomeroy's statistical profile pages, and Statsheet.com creates four factors graphs (among others) for every college basketball game.

So what's the football version of the four factors?

Due to sheer numbers, football is a pretty damn complicated sport. In basketball, you've got 10 guys on the court. In baseball, the most you'll ever have are 13. But like soccer, football's got 22. And unlike most of soccer, football's players all follow different sets of rules. These guys are allowed to touch the ball downfield. These guys aren't allowed to move beyond the line if the quarterback's still planning on throwing. The holder can have his knee on the ground, and it doesn't really count. These guys over here are 5'10, 180. Over here, 6'3, 215. And over there, 6'6, 315. In theory, you wouldn't expect a game so complex to get boiled down to its essence in a few short steps.

You'd be wrong, however. For years I've tossed around this "down to its essence" idea; in 2010, I wrote one of my favorite Varsity Numbers columns, "Four Truths," in which I discussed the importance of fast starts, big plays, passing downs, and field position. To be sure, those things are all quite important.

But over time, I've come to realize that the sport comes down to five basic things, four of which you can mostly control. You make more big plays than your opponent, you stay on schedule, you tilt the field, you finish drives, and you fall on the ball. Explosiveness, efficiency, field position, finishing drives, and turnovers are the five factors to winning football games.

  • If you win the explosiveness battle (using PPP), you win 86 percent of the time.
  • If you win the efficency battle (using Success Rate), you win 83 percent of the time.
  • If you win the drive-finishing battle (using points per trip inside the 40), you win 75 percent of the time.
  • If you win the field position battle (using average starting field position), you win 72 percent of the time.
  • If you win the turnover battle (using turnover margin), you win 73 percent of the time.

This is from 2013 college football game data. It's very, very similar from year to year.

These are good odds. And they speak to the fundamentals of football itself. You want to be efficient when you've got the ball, because if you fall behind schedule and into passing downs, you're far less likely to make a good play. You want to eat up chunks of yardage with big plays, because big plays mean both points and fewer opportunities to make mistakes. When you get the opportunity to score, you want to score. And when you give the ball back to your opponent, you want to give them to have to go as far as possible.

And you want that damned, pointy ball to bounce in a favorable way. Again, you control four of the five.

Jerome Miron -- USA TODAY Sports

Explosiveness

Slowly but surely, we're moving past total yardage as the end-all, be-all of football. It's an ongoing battle. We will still for years to come see "they're 104th in pass defense" (as in, 104th in passing yards allowed per game) as a terribly inaccurate way of saying a team's pass defense isn't very good (when it's really just saying the team sees a lot of pass attempts).

Regardless, per-play averages are catching on here and there. That's a good thing, because per-play metrics are more telling than any other basic box score stat. There's a lot you don't know when you see that Team A averaged 5.8 yards per play -- Is that a 99-yard gain and a ton of two-yarders? Is that a load of five- and seven-yard gains? -- but it is easily the best place to start in the box score.

(Note: any below data referring to 2013 college football games is actually referring to 2013 pre-bowl data. I began this project in December and didn't feel the need to update the data. Why? Because there's not much difference between 811 games and 846 -- we're dealing with more than 100,000 plays regardless. And because 2013 pre-bowl data correlated well with data from previous years when I was looking into all of this.)

Yards Per Play Margin % of 2013 games Win% Avg. scoring margin
5+ yards 4.3% 100.0% +51.0
4 to 5 yards 4.2% 100.0% +41.9
3 to 4 yards 11.2% 98.9% +32.2
2 to 3 yards 14.8% 95.0% +23.9
1.5 to 2 yards 13.8% 89.2% +17.5
1 to 1.5 yards 17.1% 86.2% +13.2
0.5 to 1 yard 20.0% 72.0% +7.7
0 to 0.5 yards 14.6% 55.1% +2.2

If you won the per-play yardage battle by even 0.1 yards per play, your odds of winning a game rose from 50% to 55%. If you averaged 0.75 yards per play more than your opponent, you won three-quarters of the time. (How much is 0.75 yards per play? At the national average of 73.9 plays per game, that's basically 55 yards.)

Predictably, it's the same story with my PPP (Equivalent Points Per Play) measure. PPP is basically a combination of yards per play and the acknowledgement that not every yard line is created equally. I assign an equivalent point value to every yard line, then assign a point value to every play. (You can see PPP in use in Football Study Hall's weekly advanced box scores.)

PPP Margin (non-garbage time) % of 2013 games Win% Avg. scoring Margin
0.7+ 4.4% 100.0% +49.0
0.6 to 0.7 2.7% 100.0% +44.4
0.5 to 0.6 5.0% 100.0% +37.4
0.4 to 0.5 7.3% 100.0% +32.7
0.3 to 0.4 11.5% 98.9% +26.8
0.2 to 0.3 15.0% 96.7% +22.1
0.1 to 0.2 25.4% 84.0% +11.7
0.05 to 0.1 14.9% 80.2% +8.5
0.0 to 0.05 13.8% 56.3% +0.1

Big plays are probably the single most important factor to winning football games. The team more adept at creating numbers advantages and getting a guy into the open field, or the team that can simply outman its opponent and win one-on-one battles will almost certainly generate more big plays and win more games. And as pointed out in my Four Truths column, big plays also allow you to avoid killing yourself.

Nothing is more demoralizing than giving up a 20-play, 80-yard, nine-minute drive. But unless your team is Navy, that doesn't happen too often. Defensive coaches often teach their squads the concept of leverage -- prevent the ball-carrier from getting the outside lane, steer him to the middle, make the tackle, and live to play another down. It is the bend-don't-break style of defense, and it often works because if you give the offense enough opportunities, they might eventually make a drive-killing mistake, especially at the collegiate level. If you allow them 40 yards in one play, their likelihood of making a drive-killing mistake plummets.

Trevor Ruszkowksi -- USA TODAY Sports

Efficiency

Of course, explosiveness isn't it. Just like OPS (on-base percentage plus slugging percentage) is better and more descriptive than pure slugging percentage, an efficiency component adds accuracy and effectiveness to an explosiveness measure.

As you probably know by now, the go-to efficiency measure for football is Success Rate, as culled from the pro side of Football Outsiders.

Our Varsity Numbers column calculates Success Rate for teams, not just running backs, using a set of baselines that differ slightly from our NFL Success Rates: 50% of needed yards on first down, 70% of needed yards on second down, or 100% of needed yards on third or fourth down.

With this, every play is deemed either successful or not, and over the course of a game or season, you can use this as an efficiency measure, as you would on-base percentage in baseball. It helps to describe a team's ability to stay on schedule and avoid drive-crippling passing downs. (How crippling are passing downs? The national success rate on standard downs was 48 percent. On passing downs: 32 percent.) Efficiency might matter more to teams without a ton of explosiveness, but on some level it matters to everybody.

Success Rate Margin (non-garbage time) % of 2013 games Win% Avg. scoring margin
50%+ 2.2% 100.0% +51.1
40-50% 2.3% 100.0% +45.5
30-40% 5.2% 100.0% +40.4
20-30% 15.7% 99.2% +31.6
10-20% 29.1% 91.5% +17.3
5-10% 22.8% 76.2% +10.6
0-5% 22.7% 59.2% +3.6

A five percent difference in success rate raises your chances of winning a game to about 75 percent, which is crazy if you think about it. That's one of 20 plays. If you are successful in nine of every 20 plays, and your opponent is successful in eight, you are going to win at least two-thirds to three-quarters of the time. Every efficient play is a big deal, even when you've got big-play ability to bail you out.

Bill Carter -- Rock M Nation

Field position

Our relationship with field position is a strange one. We know it matters, but we don't necessarily pay attention to it. We know starting a possession at your opponent's 30 or something is big, but we don't really think about the difference between starting at, say, our own 25 and our own 32.

But if explosiveness and efficiency matter so much, and if a single big or successful play can make such a difference, then it would stand to reason that the length of the field in front of us matters a lot, too. If, on average, you are starting 65 yards from the end zone, and if your opponent is starting 75 yards away, that's an enormous difference.

I talked about this at length in Chapter 11 of my book, Study Hall. Here's a clip:

A team’s average starting field position was worse than 24.0 (i.e. the team’s 24-yard line) in just 14.1 percent of the 2012 FBS vs. FBS games. It was better than 36.0 just 15.7 percent of the time. In most games, teams were trying to average in the 32-36 range (win percentage in this range: 66 percent) instead of the 24-28 range (win percentage: 32 percent).

These aren’t huge numbers. On average, a team got 13 possessions in a given game; the total difference between an average start of 26.0 and an average start of 34.0 is just 104 yards (13 possessions times 8.0 yards). One turnover could mean a difference of about 40 yards. One field-flipping punt that bounces past the punt returner and rolls a while could mean 25 yards. One huge stop on a kick return could mean 15 yards. A sack on third-and-long, instead of a short completion, could mean 15 yards. A third-down conversion that simply extends a drive from three-and-out to six-and-out could mean 10 yards. And just like that, you’re at 105 yards, and you’ve gone from likely loss to likely win.

That is a bit of an extreme example with a significant special teams impact, but one can see how smaller plays, particularly third downs, can add up quickly. And almost nothing is more devastating to your field position cause than a three-and-out, especially if a drive involves a sack or negative play on third down. Never mind the impact such a series might have on momentum; that’s significant enough. It can have an even larger impact in the field position battle.

All else being equal, the simple act of starting drives further up the field than your opponent can pay off significantly. (Of course, since field position is determined not only by special teams but also an offense's ability to get at least a first down or two before punting, "all else being equal" isn't the best way to put it. But you get the drift.)

FP Margin Range % of 2013 games Win% Avg. scoring margin
20+ yards 4.0% 96.9% +32.4
15-20 yards 8.6% 92.8% +28.6
10-15 yards 17.8% 86.7% +19.9
6-10 yards 23.5% 78.3% +15.7
3-6 yards 23.5% 59.8% +6.3
0-3 yards 22.7% 54.1% +2.6

We saw the effect of field position rather starkly in the first three quarters of the BCS Championship. Auburn kept FSU playing on 90-yard fields for most of the game, and even as the FSU offense began to click a bit, it took a while for that clicking to result in points.

Kirk Irwin -- Getty Images

Finishing Drives

If you're a Numerical reader, you know that I enjoy a rather little-used (as in, I'm pretty sure I'm the only one who uses it) stat: points per trip inside the 40. I'm not a big fan of defining only the last 20 yards as the red zone and comparing teams based on their ability to score inside the 20. There's a reason for this: there really isn't a huge range between really good and really bad red zone teams.

Or at least, there's a larger range if you look at the last 40 yards. It better incorporates place-kicking (almost every team should be expected to make a vast majority of its kicks when inside the red zone, even taking into account the general sketchiness of college kickers) and gives us a good read for which teams take advantage of even decent scoring opportunities.

Again from Study Hall:

On 104 different occasions in 2012, a team created more scoring opportunities than its opponent but lost, in part, because the opponent averaged more points in its own scoring opportunities. Washington State lost four such games, while Air Force, Florida International, Hawaii, New Mexico, TCU, Troy, and Western Michigan each lost three.

In a demoralizing loss in the Hyundai Sun Bowl, USC made six trips inside Georgia Tech’s 40 and scored just seven points. [...]

We didn’t know it at the time, but Texas A&M lost a potential national title chance on October 20 when the Aggies scored just 19 points on seven trips inside LSU’s 40 and lost, 24-19. And Florida State may have lost a similar opportunity on October 6 when the Seminoles turned six scoring opportunities against N.C. State into just 16 points, leaving themselves vulnerable to a late Wolfpack charge and a 17-16 defeat.

And in perhaps the most impressive (in a bad way) feat of the season, Hawaii created 12 scoring opportunities to Colorado State’s four on October 27 and outgained the Rams by 102 yards, but lost, 42-27. The Warriors lost three turnovers (at the CSU 30, 31, and 33), punted twice (at the CSU 39 and 40), attempted three field goals (missing one), and turned the ball over on downs at the 2. And one of the three turnovers, an interception, was returned for a touchdown.

One of the most interesting aspects of writing Study Hall was talking to coaches about this aspect of the game. Everybody agrees that it's important (obviously), and everybody had a different philosophy. When it comes to short-yardage situations, Bob Stitt of the wide-open Colorado School of Mines implements a jumbo package. Cal's air raid Sonny Dykes says, "There are a lot of creative ways to create misdirection, leverage defenders, and do the things a fullback would do."

No matter how you approach it, the game of football changes when the field shrinks. It's a good problem to have -- what are we going to do once we get close to the end zone? -- but it's a question that needs an answer. The teams that make the most trips (through efficiency and explosiveness) will win more often than not, but your ability to put points on the board once in position is its own skill.

Points Per Trip inside 40
("Scoring Opportunities")
% of 2013 games Win% Avg. Scoring margin
5.5 to 7 points 18.6% 72.8% 15.1
5 to 5.5 points 13.2% 68.4% 11.9
4.5 to 5 points 13.3% 62.6% 7.4
4 to 4.5 points 13.7% 51.8% 1.7
3.5 to 4 points 8.5% 50.4% -3.9
3 to 3.5 points 12.5% 38.5% -7.6
2 to 3 points 12.1% 23.1% -14.1
1 to 2 points 5.0% 4.9% -25.8
0 to 1 points 3.0% 0.0% -36.0

(The win percentage for the 5.5-to-7 range increases significantly when you remove teams that scored a single touchdown in a single trip.)

Not taking into account what your opponent is doing, if you are averaging at least 3.5 points per trip inside the 40 -- a pretty forgiving average if you think about the fact that means a scoreless trip for every touchdown -- you're probably going to win more than half the time. If you can get that average close to five points per trip, you're winning two-thirds of the time no matter the opponent or the quality of your defense.

Field goals are basically failures.

One other thing about this table: field goals are basically failures. They are obviously useful at times in close games, but settling for field goals is a losing strategy as a whole. Even with a good kicker, averaging three points per scoring opportunity will win you about one-third of your games. (Keep this in mind the next time your team kicks an 18-yard field goal.)

Pts Per Trip Margin Range % of 2013 games Win% Avg. scoring margin
5+ points 2.9% 100.0% 42.3
4 to 5 points 6.4% 96.0% 35.8
3 to 4 points 8.5% 94.0% 26.2
2 to 3 points 17.9% 82.3% 18.4
1 to 2 points 27.6% 74.7% 11.4
0.5 to 1 points 19.6% 65.6% 6.5
0 to 0.5 points 17.2% 57.8% 0.7

If you average more points per trip than your opponent, you win most of the time. Makes sense, right?

If you average more points per scoring opportunity, you can actually rather effectively make up for creating fewer opportunities.

Combinations % of 2013 games Win% Avg. scoring margin
More opportunities than opponent, better scoring average than opponent 26.9% 98.4% 26.8
More opportunities, same or worse scoring average 18.9% 64.8% 6.7
Same or fewer opportunities, better scoring average 21.9% 46.5% -2.6
Same or fewer opportunities, same or worse scoring average 32.3% 3.3% -24.4

(Note the specific wording. I used "same or fewer" and "same or worse" above because of ties. For instance, if you had more opportunities and the same scoring average, you ended up in the "More opportunities, same or worse scoring average" pile. That's why the first and last category and the two middle ones don't add up to 100 percent. Does that make sense?)

So basically, if you have a better scoring average but don't create more opportunities, you can still win a pretty healthy percent of the time. Punching the ball in is incredibly important.

Stephen Dunn -- Getty Images

Turnovers

And now the mushy one.

Turnover Margin % of 2013 games Win% Avg. scoring margin
+5 or more 1.6% 100.0% +30.0
+4 5.3% 93.0% +22.8
+3 11.8% 78.9% +18.2
+2 21.4% 78.6% +15.9
+1 38.0% 64.5% +8.1
+0 21.8% 50.0% +0.0

Football is about possession -- where you start it, how far you move with it, how many points you end up with from it. Turnovers take away possessions before their natural end (i.e. scoring or kicking). They also frequently create easy scoring opportunities.

On average, a turnover is worth about five points when it comes to the field position the offenses loses and the field position the defense gains for its own offense. Sometimes you get turnovers of the arm-punt variety (long bombs that are picked off, serve the same function as punts, and do little damage in the field position battle), and sometimes the defense recovers a fumble at its one-yard line and takes it 99 yards, in essence a 13-point turnover. But without even working turnover points into consideration, the impact of turnovers is obvious. A five-point swing in an otherwise easy game is going to raise (or lower) your win expectancy a decent amount.

Coaches know this, obviously, and there's almost nothing they can do about it.

A team really isn't in control of this aspect of the game. Sure, quality and style can impact the situation a bit. A better quarterback might be less likely to get his passes tipped. A better defense is slightly more likely to get its hands on opposing passes. An option offense tends to lay the ball on the ground a few more times over the course of a season. But this is only slightly in the control of the player or team.

For instance, take the ratio of a defense's passes defensed to the number of passes it faces. In theory, a good defense is going to get its hands on more of passes, yes -- sometimes that results in an interception, sometimes just a pass broken up (on average, it's about one of the former for every four of the latter) -- but the correlation isn't as strong as you would think. Whereas the correlation between the yards or points a team allowed in 2012 and 2013 was pretty strong, the correlation for this "PD-to-passes" ratio is only about 0.43. Good, not great.

Meanwhile, there is almost no correlation regarding the number of fumbles a team forces from one year to another. There is a slight correlation between sacks and fumbles forced, and good defenses tend to be a) good from year to year and b) better than bad defenses when it comes to sacking the quarterback, but that's about it.

A team has very little control over turnovers. Turnovers are a solid reason why luck determines more than one-third of an NFL game, as Michael J. Mauboussin in The Success Equation describes. And while there are plenty of differences between professional and college football, the pointiness of the ball is not one of them.

You can build a team and philosophy around the first four factors on this list. The fifth might get you fired, and there isn't much you can do about it.

*****

You can assign weight to these factors in different ways. Based on the win percentages above and on general correlations between relevant season stats and both win percentages and percentage of total points scored, I think of this as 35 percent explosiveness, 25 percent efficiency, 15 percent field position, 15 percent finishing drives, and 10 percent turnovers.

Perhaps my favorite part of the five factors idea is the way that it both clarifies a complicated game and muddies up our general perceptions of offense, defense, and special teams. Explosiveness and efficiency are pretty offense- and defense-specific, yes. But defense and special teams (kicking, punting) dictate your offense's starting field position more than your offense does, and special teams (place-kicking) plays a pretty significant role in your ability to finish drives with points.

When you go down the road of stat analysis, you realize you're going in two different directions. You're both using more complicated measures and attempting to describe your sport more simply. To build off of this, I'll be referring frequently to a lot of measures -- intuitive and less so, opponent-adjusted and raw -- but no matter the concept, the idea behind the five factors and the measures they entail is pretty simple.

You make more big plays than your opponent, you stay on schedule, you tilt the field, you finish drives, and you fall on the ball.

UPDATE: Per conversation in comments, it should be noted that if these factors are going to be used by a coach in his decision-making process -- who to recruit, who to play, how to play them, etc. -- then the factors need to be isolated more from each other: explosiveness from efficiency, field position from explosiveness/efficiency, etc. But I stand by the five factors themselves, and I look forward to a further conversation to come.

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