Skip to main content

Are You Getting Excited/Scared Because of NFL Preseason Performance? Don’t.

This weekend, the NFL preseason kicks off in Canton with the Colts and Packers. Also, the Olympics, International Champions Cup, and the Indiana State Fair are happening. So, it’s a busy time in sports and artery destruction. So definitely it’s going to be entertaining, and maybe it will impact your health in 20 years (I can dig some football, futbol, sports only on TV every four years, and random fried things). But, as you see your favorite NFL team founder, excel, or be somewhere in the middle over the next month, how much should you draw from that in terms of the next few months of your life?

Some may say very little because it’s 4 (or 5, for the Hall of Fame Game teams) games, mostly featuring back ups. And of course, the 2008 Detroit Lions managed to win every preseason game and lose every regular season game. But that is hardly a deep empirical analysis. Of course, with the limited sample size, a strict, actual winning percentage is a bad measure of team performance. Winning half your preseason games and winning 3 out of 4 is a rather similar performance, much more similar than regular season records with the same winning percentages, 8-8 and 12-4.

So, how can the performances of a team in the preseason and regular season? One tool, originating in baseball and adapted to football by Football Outsiders, is the Pythagorean expectation, which uses the points scored by and against a team to predict the record (in this case, I’m using winning percentage because they can be comparable independent of number of games played) of a team. Since there is a greater variation in those values between teams in preseason, it should allow a more realistic range of potential results. And, because the values are also very easily able to be calculated for both the preseason and regular season, it should allow a large number of data points to be compared. For football, the equation is as follows:
Pythagorean Expectation=((Points for)^2.37)/((Points for)^2.37+(Points against)^2.37)  
So, how does the preseason stack up as a predictor? Using the NFL’s data from the 2006-2015 seasons, this comparison can be easily performed (well, aside from a lot of copying and pasting from NFL.com). Not particularly well, actually. Well there is a slight correlation (a Pearson coefficient of .261), but as can be seen below, it is much more of noise than a pattern.

There are a mix of teams that excelled in the preseason and tanked in the regular season (2008 Lions), did poorly in the preseason and well in the regular season (2011 San Francisco 49er’s), and did roughly the same in both (2013 Seattle Seahawks).

So if your favorite team is doing very poorly or very well, it means nothing, right? Not exactly. There is a significant (Pearson of -.684) between a team’s preseason Pythagorean expectation and the difference between the preseason and regular season record. As shown in the graph below, this effectively means that teams that do either very well or very poorly in the preseason are likely to not be as big of a success or failure in the regular season.


Teams, on average, trend to being pretty average. So if your favorite team absolutely faceplants during the preseason, don’t be alarmed. They will probably not be terrible, just most likely mediocre. And potentially a playoff team. Which is better than the alternative. Sorry Lions’ fans.

Comments

Post a Comment

Popular posts from this blog

Brohm and Calhoun: Purdue's New Top Two Choices Analyzed

Earlier in the silly season  coaching search, the top two coaching candidates floated by Purdue's fan base were Western Michigan's P.J. Fleck and former LSU head coach Les Miles. In recent days, it has appeared neither may end up in West Lafayette. Yesterday, news-ish broke-ish that a deal was done-ish with Purdue and current Western Kentucky head coach Jeff Brohm.  Western Kentucky was revealed to be beginning its own coach search, while coach without an agent Jeff Brohm stated no deal existed and he would not think about future plans until after the C-USA championship game today. Another name floated was current Air Force Academy head coach Troy Calhoun. Which are two odd choices when considered together; at Air Force Calhoun ran a run-heavy option offense (although he has experience coaching quarterbacks in the NFL under Gary Kubiak) and Brohm's offense at WKU was a pass-oriented spread offense. Using the same methods I used to look at Purdue's last few coaches , I...
2 comments
Read more

2018 Weekly Boiler Stat Summaries: Week 8, v. an Ohio State University

I could say something emotional about the win, OR I could hope we all have our own memories that may or may not include a realization of how low our TV room ceilings are. a Bad Defense and The Great Offense Going into Saturday's game , I was pretty confident the Boilers - a pretty darn solid offense - would have success scoring against a struggling Buckeye defense. That is exactly what happened. These are numbers that should be left to stand on their own because HOLY MACKEREL PURDUE DID THAT TO OHIO STATE. Figure 1: Purdue Individual Rushing Statistics [1,2] Figure 2: Purdue Individual Passing Statistics [1,2] Only thing to note is that Purdue's rushing came mainly from some explosive runs from Knox rather than a consistent set of runs from all the backs. This isn't exactly what you want to see for success through a season (and a sign run blocking may need a bit of work), but you have to give D.J. some credit here. an Inability to Score The Buckeyes, at le...
Post a Comment
Read more

2017 Weekly Boiler Stat Summaries: Week 3, v. Missouri

Since my brother-and-law is currently a student at Mizzou, last weekend my wife, some of my wife's family, and I (later joined by some of our friends from band and ΚΚΨ) headed down to Columbia for a football game. We expected Purdue to be tested by a team that has dominated the SEC East in recent history, but struggled last season. Then something else happened. Figure 1: A Different Kind of Purdue Game My Purdue fandom has been dominated by falling short in big moments under Hope, then falling short on any moment under Hazell. (I'm in the Mechanical Engineering Class of 2015 - that should give a reference of what how little I know of successful Purdue teams.) I'm not sure how to react to something like this. Other than by being in awe of some of the numbers. Declawing the Tigers Purdue's defense was fantastic in Columbia on Saturday. The Tigers' offense, coming into the game , was not a bad group, and expectations were for a shootout. Instead, Mizzou mana...
1 comment
Read more