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Heinie Zimmerman wins the retro-active 1912 NL Triple Crown

Posted by admin on March 5, 2015

One of the things I love about SABR is how dedicated (and borderline crazy) some of the researchers are and how their years and years of work can bear fruit in unexpected ways. (I'm sure I love it because I have more than a bit of that in me as well.) In next month's Baseball Research Journal, an article by Herm Krabbenhoft will show that Heinie Zimmerman had the highest RBI total in the 1912 NL, and when paired with his undisputed batting title and 14 home runs, he won the triple crown.

8 Comments | Posted in Advanced Stats, Announcement, Baseball-Reference.com, Statgeekery

Player Comparison Tool

Posted by Mike on March 5, 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.

Comments Off | Posted in Announcement, Play Index, Pro-Football-Reference.com

SRS Calculation Details

Posted by Mike Lynch on March 3, 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.

 

2 Comments | 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

Rookie Designation Added

Posted by Adam Wodon on March 3, 2015

We have added a process to our database that correctly determines NHL Rookie status, for the purposes of using the Player Finder tools in the Play Index. For example, see the Player Game Finder, and Player Season Finder.

Now you can use those tools to do a search for true rookies, in addition to the variety of other data points you can search on.

Hockey-Reference continues to make improvements to these tools. We welcome your feedback.

Comments Off | Posted in Announcement, Hockey-Reference.com, Play Index

Find Players Older Than You Are

Posted by Mike on February 17, 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.

2 Comments | Posted in Announcement, Pro-Football-Reference.com, Trivia

Get Free Play Index Subscription with $15 Deposit on DraftKings

Posted by Mike Lynch on February 16, 2015

We're happy to announce a new promotion that allows users to get a year-long Play Index subscription (or renewal) for only $15, which is less than half of the normal price ($36).

All you have to do is make a deposit of at least $15 at this DraftKings link. Please note that this promotion is only for first-time DraftKings users. If you're unfamiliar with DraftKings, it is a site which offers daily fantasy games for cash in all of the major North American sports leagues, plus some others. Once you make your deposit via that link, we will be notified and send you an email with a coupon code for the year-long Play Index subscription.

The Play Index is our baseball research tool, which allows subscribers to make custom searches through 100 years of box scores, splits, streaks and events. You can also make custom searches for any season stat line in MLB history. A full description of the Play Index and its tools can be found here. It is the most powerful baseball research tool available to the public.

If you're already a Play Index subscriber, you can still take advantage of this offer. Your Play Index subscription will simply be extended one full year from its current expiration date.

Comments Off | Posted in Announcement, Baseball-Reference.com, Play Index

Baseball-Reference.com Server Move, 9:30am ET Thursday

Posted by sean on February 11, 2015

On Thursday, February 12th around 9:30am we'll be switching servers for Baseball-Reference.com (moving from unitas to tris). Should be no downtime #dalemurphywilling.

Comments Off | Posted in Announcement, Baseball-Reference.com, expire2d

Adding Box Plus/Minus (BPM) to College Basketball

Posted by David Corby on February 11, 2015

Just a note that we have added Box Plus/Minus (BPM) to our College Basketball site this week.

As outlined in its introduction to Basketball Reference, BPM is an advanced stat intended to measure a player's total contribution as reflected by advanced, context-dependent box-score metrics like USG% and AST%. It was developed for the NBA using regression techniques against a 14-year-long sample of historical Regularized Adjusted Plus-Minus (RAPM) data. BPM estimates the number of points contributed by a player greater or less than an average player, per 100 team possessions.

We're able to calculate BPM for seasons dating back to 2010-11 and it can be found initially on player pages in the 'Advanced' table, on our school season pages, also in the 'Advanced' table, and we've also added several advanced stats - including PER, Win Shares, and BPM - to the conference registers, along the right side of that page. (see below image). However, the best way to view BPM, as a sorted leaderboard, or according to any other criteria - is to use our Play Index search tools.

 

bpm_cbb

 

Again, our thanks to the creator of BPM, Daniel Myers, and to those whose work serves as a component. The methodology and logic of Box Plus/Minus (BPM) is discussed in our About section, and please note the section specifically for the NCAA.

 

(Note that the 'Advanced' tables on the player and schools pages have changed just a little, to accommodate the new stats. Individual ORtg and DRtg have been moved to the 'Per 100 Possessions' tables and Points Produced - the main component of ORtg - has been moved further to the left on the 'Advanced' table.)

 

* We have published BPM but not VORP for college basketball, unlike the NBA.  Value over Replacement Player (VORP) owes its meaning and derivation to a market with salaried players and teams on an equal footing, and thus an easy-to-establish theoretical "replacement level", which doesn't exist or make sense for the NCAA.

 

Comments Off | Posted in Advanced Stats, Announcement, Basketball-Reference.com, CBB at Sports Reference

Sports Reference Welcomes Adam Wodon to Our Staff

Posted by sean on February 9, 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.

2 Comments | 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

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