An Ivory Tower Take on NFL Analytics
Hey folks! I'm starting to do these kinds of analyses again, but any future work will be published at my new blog, https://skeweddata.github.io/ . Why? Two main reasons: I find myself interested in writing about more than just football analytics, and this site was really designed just for that one purpose. I wanted to have more control over the site itself. Blogger is great for quickly generating…
Between the regular season and the playoffs, there are about 44 thousand plays run in the NFL each season. That's an enormous number, and with so much happening not only in the play itself but also in the broader game-state. There's lots of cool insights in this data, but you could spend your entire life slicing it in different ways looking for them - especially if you need to do separate analyses…
tl;dr: I made a Python package to compute NFL Win Probability - given a specific game state, what are the odds the offensive team will go on to win the game? Code on GitHub , documentation on Read the Docs , or just 'pip install nflwin'. One of the most common advanced statistics used by NFL analysts is Win Probability. Put simply, Win Probability (WP for short) is an estimate of the likelihood…
Note: This post departs from the general format used on this blog. That's because the post is not about a specific analysis I've done but rather a demonstration of a tool I've been developing to make more detailed studies possible. For those not counting at home, this is the 18th post on this blog. In the last 17 entries I've investigated a wide variety of topics, from whether or not it's a good…
Abstract Principal Component Analysis (PCA) is a useful tool to simplify complex datasets. The results of the PCA can be then used either to reconstruct the original data or to classify it into different groups. In this post I apply PCA to reception data for a sample of 150+ NFL receivers. I find that PCA generally does a good job of discriminating between wide receivers, tight ends, and running…
Hi everyone! As some of you may know, I'm on the hunt for a new job – outside of academia. Unfortunately, sending out applications takes a lot of time, and despite my best efforts I can't keep doing football analytics and give the job search the attention it needs. So I'm putting PhD Football on hiatus while I figure out what I'm doing next. Once I get my work situation in order I'll get back to…
Abstract In this post I compute the First Down Probability metric, which predicts how likely a drive will produce at least one more first down for a given down and distance. I find similar overall first down conversion rates to prior studies in the literature, including that third down rushing plays are significantly underutilized. Unlike previous studies, however, I break down these rushing plays…
Abstract Where players are taken in the NFL draft is based not only on their raw skill and potential, but is highly influenced by the perceived value of the position they play as well as the overall supply of players at that position. While quarterback is clearly the most important position on the team, investigating where players at other positions get drafted may provide insights into how NFL…
One of the hallmarks of good science is reproducibility – the ability for other researchers to repeat (and thus verify or disprove) your work. While I hope I have laid out enough details in each of my posts for anyone interested to check my analyses, I am happy to report that I will now be uploading my code for each post to GitHub . Check it out! Abstract One of NFL announcers' favorite statistics…
I want to thank Kenny Rudinger for helping me check and correct some of my numbers on this analysis. Kenny is a physics graduate student at UW-Madison, a great Ultimate Frisbee teammate, and a Bills fan. His website is here . Abstract A subtle result of the (relatively) short football season is that teams have a very small sample size of games from which to determine how good they are. The fact…
While I have generally been able to maintain a semi-weekly update schedule, the next few months are going to be quite busy (that thesis isn't going to write itself). I will try to keep updating regularly, but I'm not making any promises. Feel free to check the blog regularly to see if there are updates, but if you'd rather use a more efficient method to see when I update put your email address…
Abstract A fumble can be a key play in a football game, where just a single turnover can be the difference between a win and a loss. Recovering a fumble is therefore a hugely critical act. While the recovery itself is at least a mostly random event, the location of the fumble can significantly alter the odds that the defense will recover it. Fumbles behind the line of scrimmage are more likely to…
Abs tract Crowd noise is generally considered to be a contributing factor in causing false-start penalties on visiting teams. Some stadiums are well-known for focusing deafening amounts of noise on the field, usually near the endzones. To determine if crowd noise really does cause false-starts, I compared the discrepancy between false-starts called on the home and away team as a function of…
Abstract Many franchises use high draft picks on quarterbacks, rightly understanding their importance to a well functioning team. There is enormous pressure to start these players right away, but is that a good idea? Based on a player's peak quarterback rating, the answer appears to be no. Whether this is due to the pressure of the job breaking fragile young QBs or because the teams most likely to…
Abstract Using quarterback ratings I've charted out a QB's average improvement from his first season as the starter. On average a QB sees only a minor ~10-point rating boost in his second year, with his rating remaining flat (or lower) for the rest of his career. Additionally, very few (~20%) players will ever have a season with a QB rating more than 20 points higher than their first year. These…
Abstract In addition to making the occasional blown call, multiple sources have noted that referees appear to have a subtle, pervasive, likely subconscious, home-team bias. Here I attempt to quantify that bias, using different categories of penalties to highlight any discrepancy between penalties that require no interpretation (and should not be subject to this sort of bias) and penalties that…
Introduction In the 2004 Super Bowl the first-seeded New England Patriots beat the third-seeded Carolina Panthers by three points to win their second NFL championship. 2010 featured the top-ranked New Orleans Saints earning their franchise's first Super Bowl win . In the 10 seasons since the NFL's last re-alignment ( before the 2002 season ) these are the only two times a #1 seed has won the big…
Abstract To investigate the effect that weather has on home field advantage, I've compared the average temperature difference between home and visiting teams over more than a decade's worth of games. I find that when the temperature differential is larger than 20° F the team coming from the colder city always has an advantage against the warmer-weather franchise compared to the overall home team…
Abstract Any drive's scoring chances increase as the offense moves down the field, but exactly what impact an additional X yards gained provides is not generally known (or at least not commonly discussed). In this post I've charted out a team's scoring chances for a first-down situation at any point on the field. In addition to a dramatic increase in touchdown percentage for all drives that have a…
Abstract NFL teams live and die by the draft. A franchise which drafts well consistently can look forward to years of sustained success, but just a single year of bad evaluations can cripple a team for several seasons. Drafting will never be an exact science, and it's not obvious why some teams appear to be better at it. In this post I investigate what might give these teams their advantage, and…
Abstract The existence of home-field advantage is well-known and not in dispute, but the magnitude of the home team's advantage is not often discussed. Additionally, it's reasonable to assume that while some of this effect is due to crowd noise or unconscious referee bias there may also be a component that results from the distance the away team needs to travel. It turns out that while the…