SITE NEWS: We are moving all of our site and company news into a single blog for Sports-Reference.com. We'll tag all PFR content, so you can quickly and easily find the content you want.

Also, our existing PFR blog rss feed will be redirected to the new site's feed.

Pro-Football-Reference.com ยป Sports Reference

For more from Chase and Jason, check out their work at Football Perspective and The Big Lead.

Site additions

Posted by Doug on July 13, 2009

Four new additions. These might be considered beta for now, as I'm sure there will be some cosmetic tweaks based on your feedback.

1. Approximate Value (AV) is now a column in each player's first stat stable.

2. For quarterbacks, we've added a table called Advanced Passing. In each of nine different passing rate stats, we have computed each player's standard deviations above (or below) league average for that season and converted it to an "IQ score" (average = 100, standard deviation = 15). From the glossary:

  • On all stats, 100 is league average.
  • On all stats (including sack percentage and interception percentage), a higher number means better than average
  • The greatest passing seasons of all time are in the 140s. A typical league-leading season in most categories will be in the high 120s or the low-to-mid 130s.

3. For players who were starters for at least five seasons, we've added a table of similar players. The method is nearly identical to the one outlined in this blog post, where I tried to answer the question "how would you explain Dave Duerson to some punk kid who had never heard of Dave Duerson?" (Of course, it's all relative, and I myself am often playing the role of the punk kid when players from the early 70s and before are involved.)

From the glossary:

At baseball-reference.com you'll find, for each player in baseball history, a list of players similar to that player. These lists are generated by a method introduced by Bill James in the 1980s, and his aim was to find players who were similar in quality, but also similar in style of play.

The similar players lists here at pro-football-reference are NOT the same thing.

Unfortunately, football stats just aren't descriptive enough to capture players' styles. So we have settled for a method that attempts to find players whose careers were similar in terms of quality and shape. By shape, we mean things like: how many years did he play? how good were his best years, compared to his worst years? did he have a few great years and then several mediocre years, or did he have many good-but-not-great years?

Essentially, if you run across a player you've never heard of before, and if the list of similar players has some names you recognize, this gives you a quick way to (very roughly) figure out where the guy fits in history.

Also note that each player has a list of similar players for each year of his career after the third, so you can sort of get an idea of how his career progressed. At George Webster's page, for example, you can see that the first three years of his career looked like the first three years of the careers of Dick Butkus, Lawrence Taylor, Derrick Thomas, et al. By the end of his career, he looked more like Dan Currie, Keith Bulluck, and Tim Harris.

For active players, a bit of interpretation is required. Kevin Williams has been in the league for six years. On the "6" line of his similar players table, you'll find Bob Lilly, Jason Taylor, Warren Sapp. This means that Williams' first six years look similar to Lilly's, Taylor's, and Sapp's first six years. Then Williams has a career line that includes the likes of Jerome Brown, Keith Millard, Mike Reid. This means that, if he retired today, Williams' career would look similar to the complete careers of Brown, Millard, and Reid.

4. For about 60+ coaches, like Al Groh, we now have their complete coaching resumes. We will be adding more coaching detail soon.

This entry was posted on Monday, July 13th, 2009 at 6:48 am and is filed under P-F-R News. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.