NFL: New overtime rules are a solution in search of a problem

In the 2009 NFC Championship game, the Vikings (for the most part) outplayed the Saints. But the Saints managed to force overtime, and on their opening drive, got into field goal range and kicked the winning field goal.

The problem, of course, was that the Vikings turned the ball over 5 times, and let the Saints stay in the game. The conclusion of much of the football media was different—that the Saints final score in overtime was too easy, and the Vikings should've had a chance to respond.

In response, starting with the 2010 season, the NFL implemented a new overtime rule for the playoffs. Instead of the usual sudden-death "first team to score wins" scheme, the rules were modified so that both teams would (usually) have a chance to possess the ball.

None of the 2010 playoff games went to overtime, and in 2011 season, only one playoff game that went to overtime, and that game happened to hit one of the exceptions to the "opportunity to possess" rule—if a team scores a touchdown on the opening drive, the game is over.

In 2012, the "opportunity to possess" rule was expanded to regular season games. 22 games went to overtime in the 2012 regular season. Here's how the results broke down:

Opening drive	# Games	Consequence
Touchdown	3	Game over
No score	15	Sudden death rules
Field goal	4	Other team gets "opportunity to possess"

In 3 of the 4 cases where a field goal was scored on the opening drive, the other team was unable to respond. That leaves exactly one case where the new "opportunity to possess" rules resulted in a second score (but the first team to score won anyway).

It's only been one season, and maybe things will change when players and coaches get used to the new rules, but for now there's really no evidence that the new overtime rules have solved a problem that actually exists in the field of play.

Bonus!

Here are all the playoff games where Brett Favre's final play from scrimmage was an intercepted pass in a tied game:

• 2003 Divisional Round: Packers @ Eagles
• 2007 Championship Game: Giants @ Packers
• 2009 Championship Game: Vikings @ Saints

This was also not the first time Favre had serious turnover trouble in a playoff game.

NFL: New OT rules adopted for playoffs

Like I said below, I'm not really opposed to a modification of the OT rules. But what was adopted this week... it's awful. Greg Bedard at JSOnline breaks down some cases.

The new rules are not simple. It's not "first to 6 wins". It's a hideous tangle of cases based on the new (to me, anyway) concept of "opportunity to possess". To get the full flavor of the complexity of the new rules, be sure to read down into the cases involving blocked punts, and which side of the line of scrimmage the ball is touched.

More complex rules means it will be harder for the officials to remember all the different cases. It seems inevitable that mistakes will be made—which means more controversy, and more complaining. I really wonder what it was that made the owners think this was a good idea.

Overtime Omnibus

Lately, every time PFT has a post complaining about OT rules, I think of something else to look at regarding OT games.

Here's some more OT-related stats.

Overtime margin of victory, regular season and playoffs

This is somewhat of an overlap on what I've previously posted, but I want to have the complete stats for regulation and playoffs in one place.

This is for all 445 regular-season overtime games (going back to the 1974 season), and all 27 playoff overtime games (going back to the first one, in 1958).

Margin	Reg. Season	%	Playoffs	%
0	17	3.8%	0	0.0%
2	2	0.4%	0	0.0%
3	312	70.1%	19	70.4%
6	114	25.6%	8	29.6%

The two overtime games won on a safety are here and here.

Last team to score in regulation

Back on my first post on OT rules, I suggested there is a correlation between OT winners and the last team to score in the regulation period. It turns out there is, though it's much stronger in playoff games than in the regular season.

Of the 27 playoff overtime games (the lst 24 listed here), 18 (66.7%) were won by the same team that scored last in regulation.

Of the 445 regular season overtime games, the last team to score in regulation was 224-204-17 (52.2%, counting ties as a half-win, which may or may not make any sense in this context). Not as marked as the playoffs, but still an advantage.

Home field advantage in overtime

In the playoffs, 15 of the 27 overtime games (55.6%) were won by the home teams, and 9 (44.4%) were won by the visiting teams.

In the regular seasons, 227 (51.0%) overtime games were won by the home team, 201 (45.2%) were won by the visiting team, and 17 (3.8%) ended as a tie. Counting ties as a half-win, that gives the home team a 52.7% win rate,

Note that since 1974, the home team has a 57.8% winning percentage in the regular season and a 66.0% winning percentage in the playoffs.

That 12-4 run for home teams in the playoffs

As noted at the above link, the last 16 playoff overtime games have gone 3-1 for the home team. I'd like to be able to say something about statistical significance here, but my one statistics class was a long time ago (and poorly understood even when it was more recent).

What I can do is run some empirical expermiments, under the following conditions:

• Assign a home win a probability of 55.6%.

• Simulate 27 games by generating a random number, and choosing a winner (Home or Visitor) based on that probability.

• Run this simulation repeatedly, and count how many times the 27 games end with 12 (or more) wins for the home team.

Based on the above simulation (and assumption of probabilty for a home win), it lookes like the probability of a 12-4 run is about 9.2%. Which means it's unusual, but not ridiculously unlikely.

Certainly, this agrees with my intuiton, that 27 games (particularly over the course of 52 years) is pretty thin data to draw any strong conclusions from.

Future analysis

I've actually been avoiding the main complaint against the current overtime system—that the team that wins the toss often scores on their first drive.

I have (mostly complete) play-by-play listings for all regular season (and playoff) games going back to the 2001 season, so at some point I will take a look at the 145 regular season overtime games in this period and see how often the "win the toss and immediately score" scenario happens. (Analysis for the playoff games during this period is here.)

Conclusions

It's clear that (even without the numbers on "win the toss and score immediately") losing the coin toss doesn't automatically mean lose the game.

I'm not particularly sympathetic to arguments that the Vikings were somehow cheated in the NFC Championship Game because they never got the ball on offense in overtime. The fact is, if they had managed to hold on to the ball in regulation, they likely would've won easily. And starting on defense in overtime is a disadvantage? Tell that to the Cardinals.

Still, I'm not totally adverse to some kind of "first to score six" modification of the overtime rules. I just think the "unfairness" of the current system has been overstated.

NFL: Rate of tie and overtime games

Just about two weeks ago, I posted some data analyizing the rate of playoff games that went to overtime from 1970 to 2009. That data shows a marked increase in overtime playoff games since 1999. This post takes a look at the rate of tie and overtime games for the history of the league.

How the data was gathered

• I used the data as given on pro-football-reference.com.

• Only NFL games were considered. This means the first two APFA seasons, the AAFC and AFL games are not included in this data.

• The number of teams in the league and number of games played each season has, of course, fluctuated. Therefore, the numbers for each season are presented as a percentage of games played, in order to make them as comparable as possible season-to-season.

The Data

Here is a graph of the result. The red line represents tie games, the blue line represents overtime games.

Click picture to open full size image

Comments:

• There's a surprising amount of season-to-season variation, even in the modern era, of games that are tied after four quarters.

• The rate of overtime playoff games from 1970 to 1998 (3.7%) is at the lower range of regular season overtime games during that era; the rate of overtime playoff games 1998 to 2009 (14.3%) is well over the rate of regular season overtime games.

• There doesn't seem to be an increase in the number of overtime games in the regular season since 1999. Certainly nothing as dramatic as what has happened in the playoffs.

Interesting stuff I found while looking at the data:

• The two highest-scoring tie games were both in the AFL: Raiders 43, Patriots 43 (1964), and Bills 38, Broncos 38 (1960). The highest-scoring tie games in the NFL is 35-35, which happened five times (so far), including once in the AFL.

• The team with the most ties in a single season is the NFL Champion 1932 Chicago Bears, who posted a record of 7-1-6. No other team has more than 4 ties in a season, and no team has had more than 3 in a season since 1932.

NFL Overtime Playoff Games since 1970

The overtime result of the NFC Championship Game has stirred up the usual complaints about the 'unfairness' of the overtime rules.

With that in mind, I decided to look through pro-football-reference.com's database to see how many playoff games went to overtime since 1970 (the year the NFL and AFL merged). Here's what I found (winning teams are listed in bold):

Date		Visitor		Home		Note
25	Dec 1971	Dolphins	27,	Chiefs	24	Longest NFL game played to date
24	Dec 1977	Raiders	37,	Colts	31	Ghost to the Post
9	Jan 1982	Chargers	41,	Dolphins	38	The Epic in Miami
3	Jan 1987	Jets	20,	Browns	23
11	Jan 1987	Broncos	23,	Browns	20	The Drive
3	Jan 1988	Seahawks	20,	Oilers	23
31	Dec 1989	Steelers	26,	Oilers	23
7	Jan 1990	Rams	19,	Giants	13
3	Jan 1993	Oilers	38,	Bills	41	The Comeback
8	Jan 1994	Steelers	24,	Chiefs	27
17	Jan 1999	Falcons	30,	Vikings	27	Gary Anderson's first miss of the season
30	Dec 2000	Colts	17,	Dolphins	23
19	Jan 2002	Raiders	13,	Patriots	16	The 'tuck rule' game
11	Jan 2003	Steelers	31,	Titans	34
4	Jan 2004	Seahawks	27,	Packers	33
10	Jan 2004	Panthers	29,	Rams	23
11	Jan 2004	Packers	17,	Eagles	20	4th and 26
8	Jan 2005	Jets	20,	Chargers	17
15	Jan 2005	Jets	17,	Steelers	20
14	Jan 2007	Seahawks	24,	Bears	27
20	Jan 2008	Giants	23,	Packers	20
3	Jan 2009	Colts	17,	Chargers	23
10	Jan 2010	Packers	45,	Cardinals	51
24	Jan 2010	Vikings	28,	Saints	31

Comments:

• Of the 24 games listed, 17 (70.8%) were won on a field goal.

• Notice that from 1993-2010, 12 of 16 games (75%) were won by the home team. Which suggests that playing at home is a much more important advantage than winning the coin toss.

• From 1970 to 1998, 10 of the 269 playoff games (3.7%) went to overtime. From 1999-2009, 14 of the 98 playoff games (14.3%) went to overtime. Clearly, overtime games have become much more common; this issue isn't likely to go away.

• This suggests it would be interesting to look at the rate of overtime games in the regular season during this era. However, I gathered part of this data "by hand"; there are way too many regular season games to look at unless the process is fully automated. I will eventually get to it, but not before the off season.

• The result of the first overtime drive for games from the 2001 season to present are detailed here.

NFL Playoffs, Overtime, and Winning the Coin Toss

Update 31 Jan 2010: added overtime results for 2010 playoffs.

Since 2001, there have been (at this writing) 98 playoff games played. Of these, 12 (12.2%) have gone to over time. Here is a brief summary, for each game, of the team that won the toss, and the result of their first drive:

Season	Round	Game	Won toss	Result
2001	Div	Raiders @ Patriots	Patriots	scored
2002	Div	Steelers @ Titans	Titans	scored
2003	WC	Seahawks @ Packers	Seahawks	punt
2003	Div	Packers @ Eagles	Eagles	punt
2003	Div	Panthers @ Rams	Panthers	missed FG
2004	WC	Jets @ Chargers	Jets	punt
2004	Div	Jets @ Steelers	Jets	punt
2006	Div	Seahawks @ Bears	Seahawks	punt
2007	CCG	Giants @ Packers	Packers	interception
2008	WC	Colts @ Chargers	Chargers	scored
2009	WC	Packers @ Cardinals	Packers	fumbled
2009	CCG	Vikings @ Saints	Saints	scored

It should also be observed that of the 4 games listed above that were won on the opening overtime drive, the 2009 Saints were the only team that didn't score last in the regulation period. Which suggests to me that the problem is in the losing teams' defenses, at least as much as which way the coin-toss went the sample space is too small to draw any useful conclusions.

Comments:

• 2001 Raiders @ Patriots was the "tuck rule" game. The Raiders offense never crossed mid-field after the end of the third quarter. The Patriots scored the final 10 points in regulation, and drove 61 yards in 15 plays for the game-winning field goal.

• (Since 2001) Most playoff games do not go to overtime.

• (Since 2001) Most playoff games that do go to overtime are not won on the opening drive.

• (Since 2001) In the remaining 3 games, there is at least some evidence that poor defense was as much at fault as the mis-called toss for losing the game.