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.
