# Archive for the 'Basketball-Reference.com' Category

## Introducing Box Plus/Minus (BPM)

29th October 2014

We're excited to introduce our newest statistical feature, Box Plus/Minus (BPM), developed and shared by Daniel Myers, well known as an administrator of the APBRmetrics forum and the developer of Advanced Statistical Plus/Minus (ASPM), which has performed very well empirically and to which BPM now serves as successor.

BPM is an advanced stat intended to measure a player's total contribution, calculated using box-score data that's available going back to the 1973-74 season. It follows on work done toward the Statistical Plus/Minus (SPM) concept, and ASPM, and uses long-term data sets developed by Jeremias Engelmann, the creator of ESPN's Real Plus/Minus statistic. Please visit Daniel's write-up to read more about the development of BPM, the background of the concept, and everyone that's contributed to the research.

BPM is presented intuitively, representing points per 100 possessions for which the player was on the court. For example, a player with a +4.3 BPM is said to have contributed 4.3 more points than an average player over 100 possessions, based on measurable statistical output from game box scores. The calculation makes heavy use of context dependent box score stats like USG%, TS%, STL% and others (as well as the statistical interactions between these components). We publish these as Advanced Box Score Stats and you can read about these component calculations in our glossary. Note that there is a separate calculation for the offensive component of a player's BPM, which yields both OBPM (Offensive Box Plus/Minus) and DBPM (Defensive Box Plus/Minus).

Further, BPM is scaled so that -2.0 represents a theoretical "replacement level" - thus, this concept is easily extended to permit calculations of one player's value over that theoretical threshold - that formula is [BPM - (-2.0)] * (% of minutes played), which is VORP, and interpreted as per 100 team possessions.

We'll be presenting BPM, it's offensive and defensive components, as well as VORP in the 'Advanced' table of our player pages, and likewise in our team pages:

For 2014, the leaderboards for BPM, OBPM, and DBPM, respectively, look like the following (> 1,000 MP):

And as the season gets underway, you'll be able to find BPM and its components, as well as VORP, on our actual leaderboard as well as other site features like the Play Index tools and season registers.

## New Hall of Fame Prediction Model

23rd October 2014

We maintained a Hall of Fame prediction model that, overall, works pretty well. This looks like a good list, yes?

However, keep scrolling and you'll see that a few players are slipping through the cracks. Miller is already in and good money is on both Mutombo's and Nash's eventual inductions.

So we've tweaked our model a little bit. It's no less simple than what we've been doing, but it casts a wider net around those factors that voters and the media prioritize for player inductions. Its criteria include All-Star games, leaderboard appearances, peak dominance, championships, and the player's height (yes, height!). Many of these variables are considered as well by our old model.

A necessary disclaimer is that Hall voters, to varying extents over the years, have used criteria that are difficult to account for in a simple predictive model such as college stardom, FIBA success, foreign careers, and so on. In a nutshell, we're considering plaudits earned while playing in the NBA so adjust as you wish those careers of players like Manu Ginobili and Pau Gasol who have racked up FIBA medals in addition to their pro career.

Anyway, here's the list of the top 25 retired and active players...

RETIRED:                                                             ACTIVE:

Except for Mutombo (6.4% to 86.8%) nothing changes too dramatically. Ben Wallace gets back in the race, and Nash becomes a virtual lock. Chauncey Billups and Shawn Marion move up significantly while Carmelo falls 10+ points.

To gauge your thinking about how many players "should" get in, here are the number of players in every NBA season between 1979-80 and 1999-00, inclusive, that were eventually enshrined:

We used the logistic regression method (same as before) and found that this works fairly well:

```my \$logit = -0.20303
+ -0.14203 * height_inches
+  0.80573  * championships
+  0.41568  * peak_ws
+  1.02443  * all_star_games
```

I'll get the documentation page up shortly which will explain a few of the nuances, for example how we determine "leaderboard points" and a few other particulars.

21st October 2014

Just  a note that we added per possession statistics to the player pages on our college site. In particular, we express these as per 100 team possessions, which we estimate using component stats* and which we can calculate for every D-I school beginning with the 2010-11 season.

We recently added these to Basketball Reference so that users could easily compare output from different teams or eras, however the disparities in pace of play are even greater in college. Miami (Fl.) had the slowest pace in 2013-14 at 59.1 team possessions per game. On the other hand, Northwestern State and Virginia Military Institute led the NCAA at 78.9 and 77.5, respectively.

For now you can find these tables on the player pages:

And we'll be adding per possession statistics to the school pages, season registers and play-index tools soon enough.

*team_poss = 0.5 x ((fga + 0.475 x fta - orb + tov) + (opp_fga + 0.475 x opp_fta - opp_orb + opp_tov))

## Play Index Tools Now with Short Surveys & no Ads

8th October 2014

Since we've launched the various Play Index tools on our sites, we've struggled with the best way to monetize what we feel is the deepest and most powerful set of sports data tools anywhere. We know they are useful, our users, the teams, broadcast networks, and newspaper reporters tell us so.

On baseball, we charge an annual fee of \$36, but our best guess is that the traffic and audience of the other sites would not be sufficient to make a subscription model worth our while. We have been running traditional banner ads on those pages, but they pay so little and the play index content is niche content (valuable, but niche content) so the traffic will never rise that high on the play index pages. So we have decided to remove all banner advertising and instead run Google consumer surveys on the non-baseball play index pages.

Here's how it works. The first time you run a report each day your results will be obscured and you will be asked to answer a 1-5 question survey. After you answer the survey, your requested report will be shown to you and you won't see another survey for that site on that browser for 24 hours (multi-question surveys are good for 48 hours). These surveys pay us around 5 cents per survey which, while it doesn't sound like much, is about 15 times what we would get from banner ads on those pages. Here is an FAQ if you are wondering how Google uses this information.

Also, if you find these gateway surveys a step too far, consider subscribing to our Ad-Free Access. Starting at \$20/year you can surf every Sports Reference page ad and survey free.

If you are wondering what our play index tools are, give them a try. We think you'll enjoy them.
Play Index at Pro-Football-Reference.com
Play Index at Hockey-Reference.com
Play Index at Sports-Reference.com/cbb
Play Index at Sports-Reference.com/cfb

Posted in Advanced Stats, Announcement, Basketball-Reference.com, CBB at Sports Reference, CFB at Sports Reference, Hockey-Reference.com, Pro-Football-Reference.com | Comments Off on Play Index Tools Now with Short Surveys & no Ads

## Introducing Shooting Splits With Particular Lineups

8th October 2014

Earlier this week we introduced new advanced search options into our shooting splits tool.

In case you didn't know before, we have detailed shooting data for every player since 2000-01, and detailed splits are available by going to a player's page and hovering your mouse cursor over 'Shooting':

Now, you can click on the [+] next to 'show advanced options' and you'll see two new advanced tools.

On the left, type in a player's name and click the search result to add it. In most cases, it will automatically populate as 'As teammate' or 'As opponent'. This will show shooting splits for whoever's page you are on, with the selected player both on and off the court.

In fact, you can even add several players and select custom combinations of 'On' and 'Off'.

Check out how LeBron fared versus Kawhi Leonard in 2013-14 by adding Leonard's name, then clicking on 'Go to Page'.

You can check out the numbers for just the Finals by clicking on the 'Playoffs' link in the results (likewise, you can add any split to your query the same way).

Why did Ruben Patterson call himself "Kobe Stopper". It might be these 2001-2002 numbers when Kobe went 18-63 with Patterson on the court, then 46-96 with him off:

ALSO! The tool on the right lets you compare the player whose page you are on versus any other player, or any other season. It works the same way, that is, begin typing the name in the form and then click a season from the select box that appears.

Then click 'Go to Page' and you'll get a side-by-side comparison of that player's shooting splits versus his own or another player's, in whichever season you selected:

## Introducing the College Basketball Team Game Finder

4th September 2014

I'm excited to announce the Team Game Finder as a long overdue addition to our college hoops site. This is a sibling of the very popular feature on our NBA site.

We have complete box scores going back to 2010-11 which power the game finder. You can select any criteria among a school's box score statistics, its opponent's, or the difference, as well as other important characteristics such as home/away, overtime games, regular season vs. the NCAA Tournament, and so on.

The search options allow you to span seasons, count matching instances and match against cumulative criteria, for one season or many.

We hope you find this useful and please let us know if you have any suggestions or find any bugs.

14th August 2014

Just a quick note that the NBA released 2014-15 schedules this week and we've added them to our team pages.

Some interesting games this year include the Christmas matchup of Cleveland and Miami, and also the December 23rd Cleveland at Minnesota meeting (that is, given trade speculation between those two teams).

Also, the Hornets play their first game since 2002 when they open October 29 vs. the Bucks.

The two international games this year are the Nov. 12th T'Wolves/Rockets game in Mexico City, and the Jan. 15th Knicks/Bucks meeting in London.

14th August 2014

We're excited to introduce our European Basketball site today. The new site features player and team statistics for four of Europe's most competitive leagues, Spain's Liga ACB, Italy's Lega Serie A, France's LNB Pro A, and the Greek Basket League. Europe hosts two annual transnational competitions each year, the Euroleague and the Eurocup, and we have stats for those as well.

Our database spans over 10 years for each of the featured leagues, with Euroleague and Eurocup stats spanning the life of those respective competitions (2000-01 and 2002-03, respectively).

First things first: The site is found at http://www.basketball-reference.com/euro. Otherwise, you can reach the site through the promotional blurb on our homepage, the quick links along the bottom left of the homepage, or by mousing over the links along the top of the site, e.g. 'Teams', and clicking on the Europe links...

We have player stats, team totals, standings and schedules, and we've marked some important things like playoff teams, league champions and relegated teams. The only awards that we have are MVPs, but we'll be sure to add more of those soon.

The team pages have views for each league or competition that a club played in during the season. If you want to see team and player stats across all leagues then click on 'All Leagues'. On the other hand, if you want to see statistics for club competition, or just transnational (Euroleague, e.g.) play, then click to view totals for just those seasons:

The player page shows all of the player's stats. For a 2013-14 Real Madrid player, for example, you'll see three stat tables, one for club competition, one for transnational, and one spanning both of those leagues. The former will show the teams that the player played for in those leagues, and the aggregated table will show the leagues that the player competed in:

Even tough we've just launched the site today, we're already thinking of improvements. Initially, we'd like to distinguish player stats between regular and postseason - once we've done that, we plan to add some more advanced stats. In the meantime, enjoy the 7,000 new player pages and over 1,500 new team season pages and be sure to point out any mistakes that you find.

Also! Thanks are due to Aaron Nielsen who was our source for these statistics. You can follow Aaron @ENBSports

## Corrections to 1994 Pacers Playoff Statistics

20th June 2014

It recently came to our attention that there are some conflicting scores listed by various sources for Game 6 of the 1994 Pacers/Hawks Eastern Conference Semifinals series. This prompted some digging here. As a result, we have changed our score, from 97-79, to a 98-79 final. The extra point has been awarded to Antonio Davis for making 1 of 2 FTA in the 4th quarter.

However, this also led to our discovery that some of the "official" playoff totals for the 1993-94 Pacers are not correct. They are "officially" credited with 1,444 points in the 1994 Playoffs, but if you add up all of their scores, you will get 1,445. Similarly, Antonio Davis is "officially" credited with 134 points in the 1994 Playoffs, but if you add up his game logs, you will get 135.

It is our belief that the 98th point we were missing from our Game 6 score has gone unaccounted for in NBA stat totals for the last 20 years. As such, we are adjusting the Playoff scoring totals for the 1994 Pacers. The team will now be credited with 1,445 Playoff points (rather than 1,444) and Antonio Davis with 135 Playoff points (rather than 134). Additionally, 1 FTM and 2 FTA have been added to the Pacers' total (all credited to Davis).

Thanks to this correction, Davis has moved past Larry Foust for sole possession of 219th place on our NBA all-time Playoff scoring list. Congratulations, Antonio!

## Surf Sports Reference Faster – Buy Ad-Free Access on all sites

17th June 2014

We like to keep our sites really, really fast and obsess over as many performance details as we can. Unfortunately one area where we have little control is in the performance of our advertisements as companies of our size typically outsource this task. We rely on ads for 85% of our revenue, but we are aware that some of these ads degrade our service.

We have decided to launch a new ad-free service. It's available on all of our sites and for \$20 you can surf all of our sites ad-free. To sign up see the "AD FREE" link that now appears at the top of every page.

Using this service will make your surfing experience much faster and will continue to support our site.