One common thread of
insight in NFL analysis is that teams coming off a bye week have an advantage
against their opponent. The reasoning behind this theory is the extra week of
rest allows the team to recover from injuries and scheme for the upcoming opponent.
When given two weeks to watch film and prepare of an opponent's defense an NFL
coaching staff should be able to develop the strategies needed to between them.
However, I was never convinced that the bye week actually gave teams an
advantage. So, I decided to look into the data from all 32 NFL teams over the
five season between 2010-2014 (2015 was excluded because when I created the
data set there were still teams that hadn't had a bye). I wanted to know if the
conventional wisdom was right.
On any given week
50% of NFL teams that play will win and 50% will lose. I had to use the entire
32 NFL team field for the data because considering only one conference, say the
16 NFC teams, could skew the data. If NFC teams are superior to AFC teams their
average weekly win percentage could be higher than 50%. This means a win percentage over 50% for NFC teams in
their games after a bye week might not actually show an advantage of having a
by because NFC teams always have a win percentage over 50%!
The overall win
percentage for the league coming off a bye was 51.3%. Teams won 82 games out of
the 160 they played. On a whole the Bye Week gave teams essentially no better
chance at winning than just a normal week. The extra week of rest to lick their
wounds and prepare of the next game did not help.
However, I did see
some interesting trends. Bye weeks that take place in the middle of the season
saw teams win a significantly higher percentage of games. See Table 1 for a
list of win percentage following a bye week. Teams with a Week 7 bye won at a
60% clip and teams with a Week 8 bye won 62.5% of the time. These don’t appear
to be just small sample size outliners either. Both weeks had over twenty games
of data to look at. Clearly, when the schedule is made, fans should be hoping
for their teams to draw a mid-season bye.
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| Table 1: Winning Percentage in the Game Following a Bye Week |
Teams with earlier
season bye week, in Week 4, 5, or 6, lost at an above average rate. Teams
coming off a Week 6 bye have only won 38.9% of their games. That is really bad.
It seems like something is cursing those rested teams in their week 7 games.
Continuing to look
at trends, I decided to find the correlation between the teams overall winning
percentage between 2010-2014 and their winning percentage coming off of the bye
week. According to my Excel based calculations there is a correlation between
the two of .636, which is strong. That is an expected result, nothing ground
breaking. Basically this tells us that good teams tend to win after their bye
week and bad teams tend to lose.
My best guess about why teams are failing to
take advantage of the perceived benefits of a bye week is they get out of their
rhythm. I don’t have any data or proof to back this up, but I do know from
watching and playing sports that they are all about momentum. Good plays feed
good plays by building confidence. Teams get on rolls. However, taking two
weeks off from playing a game could saps that confidence and momentum. The
benefits of healing up and getting back to full strength can be negated by the
negatives of losing that rhythm and cohesion that had been built up.
Whatever the reason
for it the data over the last five seasons of bye weeks clearly shows that
teams don’t gain an edge in their games coming off a bye. The conventional
wisdom about resting players and extra preparation makes for a nice talking
point on TV, but it doesn't hold up with the data. An extra week off isn't so
sort of magic pill to cure your teams ailments. Good teams will keep winning
and bad ones will keep losing.
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