Turnovers

The Opposite Trends of Field Goals and Turnovers

by Chase Stuart on September 7, 2018

There are only a few statistics that have clear long-term trends. And two of them happen to intersect in a notable way.

The NFL used to have significantly more turnovers. Both fumbles lost and interceptions thrown have been declining since the merger, and for the decades before then, too.

Another trend: field goal accuracy has gone up, consistently, for generations. Field goal attempts rose for much of history until 1974 — when the goal posts were moved 10 yards from the front of the end zone to the back — and then began rising again. As a result, made field goals have increased significantly.

There have been varying numbers of teams and games on team’s schedules throughout history, so the best way to think of some statistics is on a per team basis. To avoid too many decimals, let’s look at things on a per-100 team game basis for the remainder of this post.

In 1950, teams made 51 field goals per 100 team games, or just over half a field goal per game (they attempted about 1.2). Also in 1950: teams averaged 373 turnovers per 100 team games! In other words, in a given game, if you picked a random play, it was over 7 times as likely to be a turnover than a successful field goal.

In 1960 (NFL data only), teams made 104 field goals per 100 team games, and committed 286 turnovers. So now a turnover was 2.74 times as likely as a field goal.

In 1970, teams made 131 field goals and committed 243 turnovers per team game, making turnovers 1.85 times as likely as successful field goal tries.

By 1980, we were back down to 107 field goals (remember, the goal posts were now 10 yards back) and 232 turnovers per 100 team games, for a ratio of 2.17 turnovers to every field goal.

In 1990, teams made 132 field goals per team game and had 199 turnovers, the first season where teams averaged fewer than two turnovers per game. This was a ratio of 1.51 to 1.

In 2000, teams kicked 147 field goals per team and and had 188 turnovers, meaning there was only 1.28 turnovers for every successful field goal.

In 2008, teams made 165 field goals per team game and committed just 155 turnovers, the first season where there were more field goals made than turnovers forced.

And last year, in 2017, teams averaged 169 field goals per team game and only 138 turnovers, for a rate of 0.82 turnovers per field goal, the single lowest rate in NFL history.

But despite all the words I just wrote, one picture is worth more than all of them. The graph below shows the turnovers committed and field goals made per 100 team games.

Pretty crazy, eh? Entertainment is subjective, of course, but declining turnover rates and increasing field goal rates do not seem like steps in the direction of a more entertaining game.

Tagged as: Field Goals, Turnovers

{ 1 comment }

Winning The Turnover Battle

by Chase Stuart on April 24, 2017

in History

It’s one of football’s oldest maxims: the key to winning the game is to win the turnover battle. This works better as an explanation for why a team won rather than as a cause of success — correlation doesn’t equal causation, of course — but that doesn’t mean the stat is useless.

We know that turnover rates have declined significantly over the last several decades. So here’s the question of the day: does winning the turnover battle matter more or less now than it used to?

As it turns out, the importance of winning the turnover battle has been remarkably static throughout NFL history. Last year, teams that won the turnover battle won 78% of their games. And from 2007 to 2016, teams that won the turnover battle won 78% of their games. In the decade of the ’70s, when turnover rates were much higher, teams that won the turnover battle won 78% of their games. From 1950 to 2016, the average winning percentage of teams that won the turnover battle was 78%, too. Take a look: [continue reading…]

Tagged as: Turnovers

{ 10 comments }

Additional Thoughts on Turnover Rates

by Chase Stuart on February 11, 2015

in Statgeekery, Statistics

On Sunday, I looked at turnover rates for every year in the NFL since the merger. Today, I want to re-examine turnover data but in a different light. In 2014, the average team committed 23.7 turnovers. As you might suspect, there’s a strong relationship between turnovers and winning percentage, with a correlation coefficient of -0.56. This says nothing about causation, of course, and the causal arrow does in fact run in both directions (committed fewer turnovers leads to more wins, and winning in games leads to fewer turnovers).

Here’s another way to think about the relationship between winning percentage and turnovers. The Patriots were responsible for 4.7% of all wins this year and committed 13 turnovers; as a result, when calculating a weighted league average turnover total, I made New England’s 13 turnovers worth 4.7% of that total. Meanwhile, the Buccaneers and their 33 turnovers were only worth 0.8% of the weighted league average turnover total, since Tampa Bay was responsible for just 0.8% of all wins.

Using this methodology, the weighted league average turnover total in the NFL was 22.5 per team, or 95% of the unweighted league average. I used that same methodology to calculate the percentage of “weighted league average turnover total” to “unweighted league average turnover total” for each year since 1960. In the graph below, the blue line represents the NFL ratio, while the red line represents the AFL ratio. [continue reading…]

Tagged as: Turnovers

{ 6 comments }