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August 2021 Park Factor Update

31st August 2021

Today we released an update to how we calculate one-year park factors for 2020 and three-year park factors that include 2020. In short, we are giving the observed effects of ballparks in 2020 less weight, impacting context-adjusted stats like ERA+, OPS+, Rbat+, and WAR for 2019 through 2021.

There are two reasons for this change. First, the shortened 60-game season decreases the sample of games we have data from, which naturally reduces the significance of the data collected. Second, since teams only played within their own divisions in 2020, comparing scoring in home games vs. scoring in away games does not tell an accurate story of how a park impacted scoring relative to league average, since most of the parks in the league are not included in either set of games (e.g. when computing the park factor for Wrigley Field, games played at Coors Field or Citizens Bank Park are not included in the calculation anywhere, since the Cubs did not play away games at those parks in 2020).

The issue with the way we had been handling 2020 park factors became more apparent as the 2021 season went on, particularly because the Cincinnati Reds’ 2020 park factor of 119 was raising the 2021 three-year park factor, resulting in worse-than-expected adjusted stats for hitters like Joey Votto, and better-than-expected adjusted stats for pitchers like Wade Miley.

Now, when you look at a 2020 team page, the one-year park factors have been diluted so that they include an average of 60 games’ worth of 2020 data, and 51 games each of 2019 and 2021 data. If there is no corresponding 2019 or 2021 data (e.g. new ballpark in Texas, different mix of parks for Toronto), those parts are replaced with a league-average park factor of 100. These new one-year park factors are used in the three-year averages like usual, so the effect is reflected there as well.

With this change, here are some of the most notable movers in Wins Above Replacement:

Zack Wheeler (+0.5) and Aaron Nola (+0.3) each saw a bump up in their 2021 pitching WAR as the 3-year park factor for Philadelphia rose from 96 to 98 (frequent opponent Washington also had their 3-year park factor increase from 93 to 96). Wheeler’s 0.5 is the largest change resulting from this update.

Wade Miley, Tyler Mahle, and Luis Castillo (-0.4 each) saw their 2021 pitching WAR fall. As mentioned above, Cincinnati saw some of the most anomalous park factors in 2020, and mitigating their impact here lowers the expected run environment for these and other Reds pitchers.

On the hitting side, the changes are more modest. Justin Upton and Isiah Kiner-Falefa each saw their 2021 batting WAR rise by 0.3, while Maikel Franco and J.T. Realmuto lost -0.3 from their 2021 WAR.

In 2021, Shohei Ohtani is notably untouched by this update, with changes to his batting WAR and pitching WAR canceling each other out and his 7.9 total WAR remaining the same.

Here is a full list of changes to park factors, rate stats, and Wins Above Replacement from before and after this change.

Posted in Advanced Stats, Announcement, Baseball-Reference.com, Statgeekery, WAR | Comments Off on August 2021 Park Factor Update

2021 WAR Update

31st March 2021

As we approach the beginning of the 2021 season, we have made some updates to our Wins Above Replacement calculations. You may notice some small changes to figures as you browse the site. As always, you can find full details on how we calculate WAR here.

Defensive Runs Saved Changes

Last week, we updated Defensive Runs Saved (DRS) totals across the site with new figures from Sports Info Solutions that incorporate more accurate hit timing data. This impacts some fielders from 2017 to 2020. You can read more about the updates in the Sports Info Solutions blog, including which teams and fielders were most impacted.

2019 Park Factors

Park factors for 2019 have been re-computed to include the 2020 season, since WAR uses a three-year average for park factors when computing pitching WAR. The most significant change here is the Cincinnati Reds, whose pitching park factor rose from 103 to 108 (where <100 represents a pitcher’s park and >100 represents a hitter’s park). Luis Castillo sees the biggest benefit from this, with his 2019 WAR rising by 0.7 wins. All other changes to pitching WAR from updated park factors are smaller than Castillo’s 0.7 WAR gain in 2018.

2020 Park Factors

When a season is in progress, our three-year average park factors are computed using a prorated combination of the current season and two years prior. Due to the shortened 2020 schedule, the park factors for 2020 were still using some data from 2018, because the 60-game schedule was being treated as a partial in-progress season. We’ve addressed this in our park factor calculations so that the 2020 park factors only include 2019 and 2020. This change was reflected in OPS+, ERA+, Rbat+, and rOBA in the past week, but it is now also incorporated in WAR, leading to small changes for a handful of players.

Lance Lynn gains the most from this, adding 0.3 wins with Globe Life Field moving from a slight hitters park (102) to a more extreme hitters park (107). Trea Turner has the largest change on offense, also gaining 0.3 wins with Nationals Park moving from being a slight hitters park (102) to being a slight pitchers park (98).

New Game Logs from Retrosheet (1901-1903)

Last summer, we updated the site with new data from Retrosheet, including new game logs for players from 1901 to 1903. Having game-level data allows us to be more precise in our WAR calculations, since we can consider the specific ballparks a pitcher played in and the opponents he faced.

We presented a more in-depth example of this in our last WAR update, when Hall-of-Famer Christy Mathewson’s WAR rose after we added new game logs. This time around, pitcher Doc White saw the biggest change, gaining 1.5 WAR over the course of his career.

Biggest Career Movers

The top mover for position players in career WAR is Trea Turner, gaining 1.8 wins through a combination of additional runs saved and beneficial park factor changes. Trevor Story is close behind at 1.7 wins, primarily through additional runs saved.

On the pitching side, we see Doc White with 1.5 wins gained as described above. Among modern players, Patrick Corbin saw his career total drop by 0.8 wins. This is the flipside to how Turner gained credit. Corbin is debited for playing in a more pitcher-friendly park than previously thought, and for playing in front of defenders like Turner who are getting additional credit for their defense. Both of these changes decrease the number of runs we’d expect Corbin to have allowed, and as a result his performance is not as valuable as previously calculated.

We’ve highlighted some of the more extreme changes here, but to see full lists of the largest changes to season and career WAR totals, please see the spreadsheet here.

Thanks to Baseball Info Solutions and Retrosheet for their contributions. Please let us know if you have any comments, questions or concerns.

Posted in Advanced Stats, Announcement, Baseball-Reference.com, Data, Features, History, Statgeekery, Stathead, WAR | Comments Off on 2021 WAR Update

Sports Reference Purchases the Databases of Pete Palmer, Ken Pullis, and Gary Gillette

24th February 2021

February 25, 2021

Sports Reference LLC is pleased to announce that they have purchased the historical, statistical databases of Pete Palmer, Ken Pullis and Gary Gillette. This includes full historical databases for

Major League Baseball,
the National Basketball Association,
the National Hockey League, and
the National Football League.

Since their launch in 2000, the Sports Reference sites have presented and relied upon the groundbreaking and painstaking work of Palmer, Pullis and Gillette. Palmer’s pioneering work in baseball statistics has made his database the gold standard in the field, and his work with John Thorn on the Hidden Game of Baseball and Total Baseball is legendary. Pullis’s award-winning work in the field of pro football statistics formed the basis for the ESPN Pro Football Encyclopedia--the last pro football encyclopedia ever printed. Gillette created and edited the ESPN Baseball and Pro Football Encyclopedias and compiled a set of unique MLB databases for subjects like the Disabled/Injured List that previously had never been covered.

We are excited that we will now be the stewards of these databases. We intend to build upon Ken, Pete and Gary's extraordinary work. At Sports Reference, our purpose is to answer questions, so our users can grow their appreciation, understanding, and love of the game. Owning these databases will allow us to continue doing that, but also open up potential new opportunities such as making free databases available for researchers and publishing new products incorporating these datasets.

We are honored that Pete Palmer and Ken Pullis will continue the work on their databases as consultants to Sports Reference and look forward to expanding the scope of what is known about the history of North American sports. We will also be working with Gary Gillette on several special baseball projects in the future.

Sports Reference LLC is based in Philadelphia, PA and serves millions of users a month through its websites: Baseball-Reference.com, Basketball-Reference.com, Pro-Football-Reference.com, Hockey-Reference.com and others.

Pete Palmer is a titan in the field of baseball research and history and has been one of the foremost chroniclers of the National Pastime for the past five decades. He has edited or contributed to virtually every baseball encyclopedia that has been published in the last 50 years. Along with John Thorn, Palmer served as co-editor for seven editions of Total Baseball. Along with Gary Gillette, Palmer served as co-editor for five editions of the ESPN Baseball Encyclopedia. Palmer was also the co-author with Thorn of the seminal 1984 analytics book The Hidden Game of Baseball—a landmark work republished by the University of Chicago Press in 2015. Along with Gillette and Pullis, he served as co-editor of the ESPN Pro Football Encyclopedia. Palmer is also known as co-author of The Hidden Game of Pro Football and as a contributor to Total Football. He lives in Hollis, New Hampshire.

Gary Gillette is the founder and current chair of the Friends of Historic Hamtramck Stadium, a nonprofit that is working to restore the former Negro League ballpark near his home in Detroit. Gillette also served for a decade on the Tiger Stadium Conservancy’s board of directors. He has four decades of baseball research, writing, and editing experience, beginning with his work with Bill James and Project Scoresheet in the mid-1980s. A contributor to six editions of Total Baseball, Gillette later designed and co-edited with Pete Palmer the five editions of the ESPN Baseball Encyclopedia. Gillette also designed the ESPN Pro Football Encyclopedia and served as executive editor for both editions of that reference work. A former member of the Society for American Baseball Research’s (SABR) board of directors, Gillette is a past co-chair of two of SABR’s major research committees—the Business of Baseball Committee and the Ballparks Committee. He was the founder and president of SABR’s Detroit Chapter and is now the chair of SABR’s new Southern Michigan Chapter.

Ken Pullis is a retired air traffic controller and former US Air Force pilot. He has had a lifelong interest in pro football statistics and began doing original research in the late 1980s. Pullis is the 2002 PFRA Ralph Hay Award winner for Pro Football Research and Historiography and was co-editor with Gillette and Palmer of the ESPN Pro Football Encyclopedia, volumes 1 and 2. He currently resides in Vermilion, Ohio.

Posted in Announcement, Baseball-Reference.com, Basketball-Reference.com, Expire30d, Hockey-Reference.com, Pro-Football-Reference.com, Statgeekery, Stathead | 3 Comments »

FBref Scouting Reports and Similar Players Launched

10th February 2021

FBref is happy to announce the release of a feature we've been excited about for a while, player Scouting Reports that give you a quick look at how players compare in various statistics to other players at their position. This is currently available for players in the Big Five men's European leagues (example: Mohamed Salah), Major League Soccer (example: Diego Rossi) and the Women's Super League (example: Sam Kerr). We show 20 categories on the main Scouting Report at the top of a player's page, selected based on feedback from user research and industry experts, but you can also click through to a Complete Scouting Report which shows many more categories to compare the players by.

In addition, we have added a Similar Players table which locates the players that have the most similar percentiles in the stats used in the Scouting Reports. That table also offers Compare links which takes you to our Player Comparison tool so you can see the players' statistics side-by-side.

For more information on how the Scouting Report works, we have a longer explainer on FBref. This would not be possible without the wide array of advanced stats provided by Statsbomb, so thanks to them.

Depending on how people react, we could even adapt this feature for our other Sports-Reference sites in the future. Because of that, we are eager to hear people's thoughts on this new feature, so feel free to contact us via our feedback form.

Posted in Advanced Stats, Announcement, FBref, Features, Statgeekery | Comments Off on FBref Scouting Reports and Similar Players Launched

December 2020 WAR Update

14th December 2020

We recently fixed an issue where, because of the abbreviated 2020 season, we were not allocating enough wins to position players when calculating Wins Above Replacement. We have fixed this issue across Baseball-Reference. With this change, no position player gained more than 0.3 WAR, and no position player lost WAR. All pitcher WAR remained the same.

You can review the changes for each player here: https://docs.google.com/spreadsheets/d/18WY53wSt0GrBMMijLiIFMhVtvbmjuhbYNOaTvHfs-gE/edit?usp=sharing

If you have any questions or concerns, feel free to contact us through our feedback form.

Posted in Advanced Stats, Announcement, Baseball-Reference.com, Data, Statgeekery, WAR | Comments Off on December 2020 WAR Update

ABA Game-Winning Buzzer-Beaters Added to Basketball Reference

29th August 2020

In February Basketball-Reference added a list of every Game-Winning Buzzer-Beater in NBA history. Today, we're happy to announce that we've also added a list of every Game-Winning Buzzer-Beater in ABA history.
Read the rest of this entry

Posted in Announcement, Basketball-Reference.com, Data, Statgeekery | 1 Comment »

Sports Reference LLC Acquires The Baseball Gauge

27th August 2020

Sports Reference LLC has acquired the Baseball Gauge from owner Dan Hirsch. Dan was hired as a developer by Sports Reference in 2018 and has spearheaded our work on fbref.com. This week, Dan migrated the MLB.TV dashboard from the Baseball Gauge to a new home on Baseball-Reference.com. Work is continuing on the migration of additional features like Championship Probability Added and Championship Leverage Index.

Following the re-launch of these features on Baseball-Reference.com, The Baseball Gauge will be shut down. You can follow Dan on Twitter.

Posted in Announcement, Baseball-Reference.com, General, Statgeekery | 2 Comments »

What’s a Home Game on Baseball-Reference.com? HTBF?

6th August 2020

With Major League Baseball making a mad dash to complete the 2020 season, a number of norms and standards have gone by the wayside this season. Due to postponements, cancellations, and Canada's need for a quarantine of those playing America's Pastime, MLB has been forced to schedule what they've considered home games to be played on the road. In these games, the host team bats first and they often go through the charade of wearing their road unis while the traveling team wears their home whites. We handle these games in a certain way and this has led to confusion as to what the home and road records and splits represent on Baseball-Reference.com.

Our policy has been and remains that a team playing in their home park is the home team regardless of whether they bat first or second (we call these Home Team Batted First or HTBF). We feel that home and visitor refers to location and not batting order. In a neutral site game (of which there have been very, very few), the home team would be the team to bat last. Since 2007, there have been 19 games where the home team batted first, those are listed below.

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Posted in Academics, Baseball-Reference.com, Ridiculousness, Stat Questions, Statgeekery, Uncategorized | 1 Comment »

Adjusted Shooting Stats Added to Basketball Reference

1st June 2020

There's been much debate about the greatest players in NBA history of late. One of the most difficult things about ranking players in a league with 70+ years of history is that the game has changed a lot over the years. Sure, some of it has to do with the skill and quality of the players. But some of it also has to do with the quality of the balls, the floors, the rims, the training, the travel, the accommodations, available nutrition and pretty much any other variable you can think of. For a better idea of how the league has changed over time, please see this table of league averages for each season in the history of the NBA. As you can see, 2019-20 is the fifth straight season in which a new league-wide eFG% record has been set. There are clearly things at play here beyond just player improvement. Though today's players are certainly more skilled than the ones that produced a league-wide 27.9 FG% in 1946-47 (the first year of the NBA's 'official' forerunner the, BAA, which was objectively worse than the league it eventually merged with, the NBL).

To help bring a bit of objectivity to cross-era comparisons, we have added an Adjusted Shooting table to all player, team and season pages. These tables will show a player's shooting percentages and tendencies, as well as league-wide percentages and tendencies and then scale them. Like OPS+ on our baseball site it will be scaled so that 100 represents a league-average shooter. 125 is 25% better than average and 75 is 25% worse than average. These figures are obtained by taking the player's shooting percentage, dividing it by the league-wide shooting percentages and then multiplying it by 100. So 125 doesn't mean a player was 25 percentage points above average, but 25 percent above average. We are also publishing adjusted versions of 3-point Attempt Rate and Free Throw Rate to give a better idea of how often the player shot 3s or got to the line relative to their era.

Additionally, we have calculated Field Goal Points Added and True Shooting Points Added to show how many points each player scored above or below what a league average player would have scored given an equal number of field goal attempts or true shot attempts, respectively. This is to show which players combined volume and efficiency (or those that combined volume with inefficiency, for that matter).

Read the rest of this entry

Posted in Advanced Stats, Announcement, Basketball-Reference.com, Data, Features, History, Statgeekery | 7 Comments »

Game-Level BPM In Play Index + Box Score Mouseovers

4th May 2020

In February, Basketball Reference made a major update in incorporating Daniel Myers' BPM 2.0, which aims to estimate a player's performance relative to league average by using a player's box score information and his team's overall performance. This statistic is also calculable at the game level, and we've made it easier to look through this by making BPM searchable in Basketball Reference's Game Finder, one of the many tools you can find in the site's Play Index.

BPM 2.0 is searchable back to the 1984-85 season, when we first have 100% coverage of all the statistical components needed to calculate this. It's important to note that BPM is a rate stat, so setting a minutes played threshold will be important. Here's a look at the top games in our system using a couple of different thresholds:

Minimum 10 MP

Query Results Table
Player Date Tm MP TRB AST PTS BPM
James Robinson 1996-12-30 * MIN 10 1 1 23 74.6
Henry James 1997-04-15 * ATL 10 2 1 24 63.9
Jrue Holiday 2009-11-24 * PHI 10 6 1 11 61.1
Provided by Basketball-Reference.com: View Original Table
Generated 5/5/2020.

Minimum 20 MP

Query Results Table
Player Date Tm MP TRB AST PTS BPM
Brent Barry 2006-03-24 * SAS 20 2 4 23 45.5
Manu Ginóbili 2009-01-20 * SAS 21 8 3 26 41.9
Victor Oladipo 2018-01-06 * IND 24 6 9 23 40.6
Provided by Basketball-Reference.com: View Original Table
Generated 5/5/2020.

Minimum 30 MP

Query Results Table
Player Date Tm MP TRB AST PTS BPM
Nikola Jokić 2018-10-20 * DEN 31 11 11 35 44.4
Gilbert Arenas 2006-02-25 * WAS 30 1 2 46 40.5
Damian Lillard 2016-02-19 * POR 31 0 7 51 38.1
Provided by Basketball-Reference.com: View Original Table
Generated 5/5/2020.

Minimum 40 MP

Query Results Table
Player Date Tm MP TRB AST PTS BPM
Damian Lillard 2017-04-08 * POR 42 6 5 59 35.7
Manu Ginóbili 2008-02-13 * SAS 41 5 8 46 34.2
Vince Carter 2001-05-11 * TOR 45 6 7 50 34.0
Provided by Basketball-Reference.com: View Original Table
Generated 5/5/2020.

In addition to the Game Finder addition, Basketball Reference now has mouseovers in the advanced section of box scores that display the offensive and defensive BPM breakdowns, as well as Value Over Replacement Player prorated to 82 games. For more information on how BPM 2.0 is calculated, please consult Daniel Myers' explainer. Stay tuned to the Sports Reference Blog for the latest additions to Basketball Reference!

Posted in Advanced Stats, Announcement, Basketball-Reference.com, Features, History, Play Index, Statgeekery | 1 Comment »