29th April 2015
With the NFL Draft rapidly approaching (thus bringing an close to the endless months of draft prognostications), now might be a good time to point out all the draft resources we have available at Pro Football Reference. You can check out:
Hopefully these are of some assistance to you as you're tuned into the draft wondering if your team is going to pick the next Peyton Manning or.. not.
Posted in Announcement, Pro-Football-Reference.com | 1 Comment »
22nd April 2015
The 2015 NFL schedule is up on the site now, so a couple of quick notes:
Posted in Announcement, Pro-Football-Reference.com | Comments Off on 2015 NFL Schedule
21st April 2015
We're excited to announce that we have a released an NFL Draft app on the Google Play store and Apple's App Store: the PFR Draft Machine. For users familiar with our Play Index Draft Finder tool, this brand new app will bring those same unique functions (and more) to your mobile devices.
Download this app now to find out who's picking where in 2015, the best pick at that position in the history of the draft, and the average performance of picks at that position. This app also allows users to make customized queries across every NFL draft pick in history, with filters such as year, team, college, position, round, etc. The only limits to your queries are your own imagination. This is the only app to bring the power of the Pro Football Reference Play Index to your mobile device.
And best of all, we're offering this app for FREE. So please download it and let us know what you think. We're eager to hear your feedback and apply it to any future mobile apps.
Download this app from the Google Play Store
Download this app from Apple's App Store
We have attached some sample images below:
Posted in Announcement, Data, Draft, Features, History, Play Index, Pro-Football-Reference.com | Comments Off on Introducing the PFR Draft Machine App for Mobile Devices
17th March 2015
You may have noticed that we've added trades to the bottom of player pages (which also reflects if the player's draft pick was traded). Since we have now gotten that data populated to 1994, I figured I would commemorate 20 years worth of trade data by building a trade finder tool. You can use this to find:
As I said, this data is complete back to 1994 with more years to come as I feel like digging out the NFL Record and Fact Books and entering them. Let us know in the comments or via the feedback form if you have any other suggestions for this tool.
Posted in Announcement, Pro-Football-Reference.com | Comments Off on New Trade Finder Tool
5th March 2015
Today we're rolling out an often-requested feature here at Pro Football Reference: a player comparison tool. Simply select up to 6 offensive skill position (QB, RB, WR, TE, etc.) players and it will display their career and per-game regular season stats and career and per-game playoff stats in one table for easy sorting. Use it for:
In addition, you can use it to compare players through a particular year of their careers (for instance John Elway through 5 years vs. Joe Montana through 5 years) or compare a specific single year among players (for instance a bunch of 38-year-old quarterbacks). Hopefully this will hope settle (or provoke) some longstanding arguments, so have fun with it.
Posted in Announcement, Play Index, Pro-Football-Reference.com | Comments Off on Player Comparison Tool
3rd March 2015
One of the more common subjects for queries we receive at Sports-Reference is our SRS (Simple Rating System) figures. For some background, the first of our sites to add SRS was Pro-Football-Reference, when Doug Drinen added it to the site in 2006 and provided this excellent primer. The important thing to know is that SRS is a rating that takes into account average point differential and strength of schedule. For instance, the 2006-07 Spurs won games by an average of 8.43 points per game and played a schedule with opponents that were 0.08 points worse than average, giving them an SRS of 8.35. This means they were 8.35 points better than an average team. An average team would have an SRS of 0.0. The calculation can be complicated, but the premise is simple and it produces easily interpreted results.
However, there are some variations in the way we calculate SRS across our various sites. We'll break down these differences below.
Pro-Football-Reference.com SRS: PFR's SRS is unique in that a home-field advantage is included as a part of the calculation because of the short schedule compared to the other sports (we don't want a team to look relatively weak at the halfway point because they've only played 3 of their first 8 at home, for instance). This HFA fluctuates yearly based on game results, but it is generally somewhere between 2 and 3 points (2006 being an outlier, as you'll see). Below is a look at the HFA numbers we have used since 2001. If you'd like to calculate these HFAs yourself, just sum up every team's home point differential and then divide by the total number of games played across the league that season. This data can easily be found in the Play Index for each season:
- 2001: 2.0081
- 2002: 2.2461
- 2003: 3.5547
- 2004: 2.5078
- 2005: 3.6484
- 2006: 0.8477
- 2007: 2.8672
- 2008: 2.5586
- 2009: 2.2070
- 2010: 1.8945
- 2011: 3.2656
- 2012: 2.4336
- 2013: 3.1055
- 2014: 2.4883
College Football SRS: Our CFB SRS does not contain a home-field advantage element, but it does have some other quirks. Most importantly, we have capped the margin of victory considered for the formula. Due to the number of mismatches seen in college football, the maximum point differential a team can be credited with in a game is 24. We also credit all wins as a minimum of plus-7 margin of victory (so if you win by 1 point, it's treated the same as a 7-point win). The same logic is applied to losses, as well. One other wrinkle for CFB is that all non-major opponents are included as one team for the sake of the ratings.
College Basketball SRS: SRS for college hoops is straight forward (no HFA & no adjusted MOV), but one item to note is that games against non-major opponents are not counted in our calculations.
MLB, NBA & NHL: All of these SRS calculations are straight forward with no adjustments for HFA and no capping of MOV. It should be noted, however, that no special consideration is given for extra-innings, overtimes or shootouts, either.
We'll close with a quick rundown of the various merits and weaknesses of SRS, from Drinen's original 2006 post. These bullet points were created to describe the system used for NFL SRS, but many of the strengths and weaknesses can applied to the other sports, as well:
- The numbers it spits out are easy to interpret - if Team A's rating is 3 bigger than Team B's, this means that the system thinks Team A is 3 points better than Team B. With most ranking algorithms, the numbers that come out have no real meaning that can be translated into an English sentence. With this system, the units are easy to understand.
- It is a predictive system rather than a retrodictive system - this is a very important distinction. You can use these ratings to answer the question: which team is stronger? I.e. which team is more likely to win a game tomorrow? Or you can use them to answer the question: which of these teams accomplished more in the past? Some systems answer the first questions more accurately; they are called predictive systems. Others answer the latter question more accurately; they are called retrodictive systems. As it turns out, this is a pretty good predictive system. For the reasons described below, it is not a good retrodictive system.
- It weights all games equally - every football fan knows that the Colts' week 17 game against Arizona was a meaningless exhibition, but the algorithm gives it the same weight as all the rest of the games.
- It weights all points equally, and therefore ignores wins and losses - take a look at the Colts season. If you take away 10 points in week 3 and give them back 10 points in week 4, you've just changed their record, but you haven't changed their rating at all. If you take away 10 points in week 3 and give back 20 points in week 4, you have made their record worse but their rating better. Most football fans put a high premium on the few points that move you from a 3-point loss to a 3-point win and almost no weight on the many points that move you from a 20-point win to a 50-point win.
- It is easily impressed by blowout victories - this system thinks a 50-point win and a 10-point loss is preferable to two 14-point wins. Most fans would disagree with that assessment.
- It is slightly biased toward offensive-minded teams - because it considers point margins instead of point ratios, it treats a 50-30 win as more impressive than a 17-0 win. Again, this is an assessment that most fans would disagree with.
- This should go without saying, but - I'll say it anyway. The system does not take into account injuries, weather conditions, yardage gained, the importance of the game, whether it was a Monday Night game or not, whether the quarterback's grandmother was sick, or anything else besides points scored and points allowed.
Posted in Announcement, Baseball-Reference.com, Basketball-Reference.com, CBB at Sports Reference, CFB at Sports Reference, Data, FAQ, Features, Hockey-Reference.com, Pro-Football-Reference.com, SRS, Stat Questions, Statgeekery, Uncategorized | 2 Comments »
27th February 2015
Posted in Announcement, Baseball-Reference.com, Basketball-Reference.com, CBB at Sports Reference, CFB at Sports Reference, expire21d, Hockey-Reference.com, Olympics at S-R, Pro-Football-Reference.com, Statgeekery | Comments Off on Hiring: Analytics Consultant, Posted Feb 27, 2015
17th February 2015
With the retirement of Jason Giambi I've seen some talk from people that there are now no longer any MLB players older than them. Since I'm never one to pass up on the opportunity to make a relatively useless tool, I've added a quick Pro Football Reference page to find active NFL players as old or older than you are. Basically, we just need to hope that Adam Vinatieri keeps kicking.
Posted in Announcement, Pro-Football-Reference.com, Trivia | 2 Comments »
9th February 2015
Adam Wodon has joined Sports Reference today as a Managing Director for Hockey Reference. Adam will be working out of our Philadelphia office as our staff size has now risen to six. Adam brings a great deal of development experience and hockey knowledge to Sports Reference. Adam is the founder and managing editor of College Hockey News. Adam is an Isles fan through and through and also supports the Mets, Jets, and Nets making him the first diehard National League fan on staff. Adam is also on twitter at (@chn_AdamWodon).
Hans VanSlooten (@CantPitch) who had been working on the hockey site for the last 14 months will be taking over primary day-to-day development of Baseball-Reference.com.
Posted in Announcement, Baseball-Reference.com, Basketball-Reference.com, CBB at Sports Reference, CFB at Sports Reference, Expire30d, Hockey-Reference.com, Olympics at S-R, Pro-Football-Reference.com | 2 Comments »