Sure it seems plausible that facing teams coming off a bye week is not the best of situations. Assuming your team is not coming off of a bye itself, the opposition has had both a greater chance to rest and heal, and to figure out strategy to deal with your team. But does this seeming advantage translate to extra wins? That's the main question this post tries to answer.

To answer this, and related questions I took a look at data representing the last 10 NFL seasons. The data was readily available at Pro-Football-Reference.com in CSV format, so a big shout out to this site for making this aspect of the job so convenient. Next, I pulled the data first into Microsoft Access for the initial transformations and cleanup, and then into Microsoft SQL Server where the heavy lifting, including calculations of the prep time for each team/game was done. In the IT world this type of activity is called an ETL (for extract, transform and load) routine, and the end result is a data warehouse or data mart.

There were 2 tie games in this 10 season time span. I eliminated these games from the data as they would have skewed the results.

In addition to the data mart I also built a front end page that will show detail on the actual games that the summary results for each section represent. You can click on the links to display the results.

Overall outcomes by prep time

I first looked at the set of all games where there was at least some disparity in prep time.

There didn't seem to be too much advantage to having extra prep time, so I decided to dig a little deeper.

Outcomes by discrepancy in prep time

Next, I broke down the outcomes by discrepancy in prep time. I thought that it might be the case that as the disparity between the winner and loser's prep time grew, so might the win percentage of the advantaged teams.

There are some seemingly counter-intuitive results here. For instance, where there is a one day disparity in prep time, the disadvantaged teams won almost 54% of the games. This result might be explained by better teams being featured on Monday night football. Another seeming anomaly is that only 40% of games were won by a team with an 8 day advantage in prep time, but perhaps this can be explained by the relatively small number of games played with this disparity.

The results for 6 and 7 day disparities fall in line with my initial expectations. These larger disparities yield outcomes that favor the advantaged teams by larger margins then the smaller disparity categories. I'm not going to say these results are "statistically significant", because frankly I couldn't find a coherent explanation on the web as to what this means. Maybe some of you out there with Stat backgrounds can weigh in on this. Instead of heading down the academic path, I thought it might be useful to compare the 57.090 win percentage of the advantaged teams in 7 day disparity games with the win percentage of the home team over the same time period. As we all know, Vegas puts the home field advantage at 3 points. It should be interesting to see which win percentage is larger.

Outcomes by location

This is just a simple Home/Away breakdown:

What the seven day advantage in prep time is worth in terms of points

As we all can see the win percentage of the those teams enjoying a 7 day advantage in prep time over their opponents (57.090) is virtually identical to the win percentage of home teams(57.374). If the home field advantage is 3 points, then the "bye prep" advantage is 2.985 points to be exact. But c'mon man - I say call it a field goal and leave it at that.

Bye games - which teams have benefited or been hosed by the schedule makers

Assuming that the "bye prep" advantage is worth 3 points, to which teams have the NFL schedule makers been giving those field goals to? The answer can be found in the following table. Sorry about the big blast of data, I would have put the table in a containing element with scrollbars but the BGN fanpost tool wouldn't let me. This is a breakdown by team and year of seven day discrepancy prep time games. The Count Of Adverse Games column is the number of games that the team has the disadvantage in prep time, Count Of Favorable games shows the opposite. The Hose Factor column is Adverse Games minus Favorable Games. The higher this number the worse the hosing! As you can see, the Falcons and Cowboys have the highest Hose factor in the last 10 years - The Falcons in 2009, and the Cowboys in 2003. But note that the Eagles schedule this year, as both JimmyK and GreenInBaltimore have pointed out is equally as bad. (Note: The following table is reporting results for 2012 but does not include games for the 2012/2013 season, only the results from week 17 of the 2011/2012 season. Thanks to Udalango for bringing this to my attention.)

Conclusion

The "bye prep" advantage, at least when looking at the last 10 seasons of data turned out to be bigger then I thought. An article linked to by JimmyK's second post on this topic states that "Since 1990, when the bye was first introduced, 52.6% of teams have followed up the bye with a victory." It is possible that outcomes of bye games in earlier years turned out a little differently. However it might also be true that the set of data that I chose to work this is a more accurate representation of the situation now, since it is more recent. Also the author of this article doesn't cite his source for where he got the data from. Let him show me his data warehouse :).

I guess that's it for now. I suppose I could go into further detail regarding the success of individual teams when they're in the bye situation, but maybe I'll save that for another post. Please let me know if you see any issues or problems with anything I've posted.