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New Team Roster Features

Posted by David Corby on May 7, 2015

 

Just wanted to show off a couple new features that we've recently introduced...

 

When you find yourself on our team season pages look for the "Game-by-game roster status" links:

 

roster_status_link

 

These will bring you to a Roster Status page with a color-coded visualization of each player's roster status for the 82 regular season games, and the playoffs. Designations include Starter, Reserve, DNP, Inactive, and Suspended. Note that a player's status is also noted on boxscores and our player gamelogs. Notable in 2014-15 are the Raptors, Bulls, and Magic, all of whom maintained a stable roster throughout the season. The Sixers page is a lot of fun to look at, too.

We've published these going back to 2013-14, and should hopefully extend that period at some point.

 

rockets_screenshot

 

 

The other new feature is a historical time series of roster continuity for each currently-active franchise. Our accounting begins with 1952-53 given that the season prior is the first for which we have Minutes Played data for every league player.

Several years ago former colleague Neil Paine published some musings on our blog about Team Continuity, and Dean Oliver devotes a couple pages in his Basketball on Paper book in the context of historically bad teams. The Spurs are well-noted stalwarts of year-to-year stability - on the other hand, the Cavaliers and Mavericks show that it's possible to turn over most of your minutes and not come apart at the seams, especially if one of your newcomers is LeBron James.

You can find a link to this page on our Frivolous Pages index, under Roster Continuity.

 

continuity

 

 

Comments Off on New Team Roster Features | Posted in Advanced Stats, Announcement, Basketball-Reference.com, CBB at Sports Reference, Data

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

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 on Adding Box Plus/Minus (BPM) to College Basketball | Posted in Advanced Stats, Announcement, Basketball-Reference.com, CBB at Sports Reference

Box Plus Minus/VORP for the Playoffs

Posted by David Corby on February 9, 2015

 

Playoff Box Plus/Minus (BPM)

We're now able to calculate Box Plus/Minus (BPM) and Value Over Replacement Player (VORP) for the playoffs, by extending the methodology used for the regular season, and calculating a team efficiency rating based on performance in the playoffs, adjusted for strength of playoff lineups (by using playoffs minute distributions and regular season BPM ratings). These ratings are interesting in themselves, and reflect some of the great playoffs runs - the 1996 Bulls' rating was +19.3, and the 2001 Lakers were +20.1.

The BPM figures themselves reflect the best individual playoff performances. LeBron's 2009 BPM of 18.2 is tops by a large margin, followed by Kareem's 1977 run and then the Jordan playoffs from 1989-1991.

(For a detailed explanation and further discussion see the "Playoff Box Plus/Minus and VORP" section of the write-up.)

 

Playoff VORP (and Pro-Rating the Regular Season)

As well as BPM, we can now calculate VORP for the playoff season. (If you need a refresher on VORP as a concept, please visit the original write-up when we introduced it to Basketball Reference). We calculate VORP for the playoffs similarly to the regular season - that is, [BPM - (-2.0)] * (% of minutes played) - and it should be interpreted identically. Again, that's as the number of points the player has produced over a replacement player, per 100 team possessions.  The significance of VORP compared to BPM is that it's accumulative, rather than a rate stat, and thus accounts more literally for value provided, weighted as it is by minutes played, and expressed on a per-82 game basis*.

(* - Yes, this is new. We are now pro-rating VORP based on the number of games that a team has played during the regular season, and doing the same for the playoffs. One point of VORP is one point of full season team efficiency differential. This affects partial seasons, strike-shortened seasons, and the playoffs.  This has significance for the playoffs, in particular - players on teams that go further or play in 7-game series will accumulate more because they have more opportunities.)

 

Some Minor Changes to the Equation

Please note that we've also updated the methodology, such that some players will have a slight variation in the BPM and associated stats. These were technical fixes to the regression methodology, which had the result of slightly changing the relative value of component stats. For example, blocks and shooting efficiency are two factors that are more highly favored by the revision and thus Anthony Davis saw the largest increase in BPM (+0.8), however most changes were of a much smaller magnitude. Please see the details of this revision in the write-up, under the "Updates" section.

 

Again, Basketball Reference extends its thanks to Daniel Myers, whose research the above represents. Also, please see the revised 'About BPM' write-up that details the methodology and is generally extremely useful for understanding the context of BPM and VORP, and the best ways to think about and use these stats.

 

 

 

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

Small Additions to the Player Season Finder

Posted by David Corby on January 6, 2015

Just a note that we've added 3-Point Attempt Rate (3PAr) and Free Throw Attempt Rate (FTr) to our Player Season Finder.

In addition, we've expanded the group of shooting stats that we show by default, now including both eFG% and TS%.

This should help you keep tabs on Kyle Korver's historic sharpshooting...

 

psl_new_stats2

 

 

Comments Off on Small Additions to the Player Season Finder | Posted in Advanced Stats, Announcement, Basketball-Reference.com, CBB at Sports Reference

Games Started, Quality Starts on Hockey-Reference.com

Posted by Hans Van Slooten on December 9, 2014

We've added four new measures to goalies on Hockey-Reference.com, Games StartedQuality Starts, Quality Start Percentage, Really Bad Starts. These should be available anywhere you see goalie stats on the site currently, including the Play Indexes.

Games Started (GS) should be fairly obvious, this is the number of games that a goalie started (i.e. did not come in for another pulled goalie).

Quality Starts and Quality Start Percentage were developed by Rob Vollman, and are described in his Hockey Abstract. Here is a brief description, but we encourage you to pick up a copy of his book for additional discussion of this statistic (and many others):

Quality Start (QS) is when the goalie achieves at least the mean save percentage (for the season) in a game. For the 2013-2014 season that percentage is 91.5%. So, if Tuukka Rask allows only 2 goals on 28 shots (a 92.9% save percentage), that is considered a Quality Start. There is an additional criteria for low shooting games: if a goalie faces 20 or fewer shots, he only needs to get an 88.5% save percentage. The relationship between save percentage and winning percentage (and hence the definition of Quality Start) is shown here (prior to 2009-2010):

Save % Win %
0.913 or better 0.777
0.900 to 0.912 0.536
0.885 to 0.899 0.503
0.884 or worse 0.246

Quality Start Percentage (QS%) is simply the number of Quality Starts / Games Started. This gives you a sense of how often the goalie has a Quality Start. A good rule of thumb for this stat is that anything less than 50% is bad, anything over 60% is among the league leaders, and the league average for an NHL regular is about 53.4%. Also, according to Vollman: "Based on the average of every goalie with fewer than ten starts in a season, the average for replacement -level goalies is 42.8% but, in fairness, there is some selectino bias involved in this since playing that poorly will generally limit you to ten start in the first place."¹

Really Bad Starts (RBS) is another stat coined by Vollman that is "awarded" whenever a goalie has a save percentage in a game less than 85%. A team only has a 10% chance of winning when the goalie has save percentage that low.

Where to find these new stats

"So," you are asking, "where do I find these new stats?" They are available anywhere goalie stats have been listed on the site. Due to a limitation of our data source, they are only available going back to the 2007-08 season. So, if you go to a goalie page, you'll see the stats listed in the NHL Standard and NHL Playoffs sections.

Additionally, you can see the league-wide stats on the yearly page for a league. For instance, the 2015 stats are available here.

Finally, the stats are available on the Player Season Finder for goalies and the Player Playoff Finder for goalies.

As always, we welcome any feedback.

2 Comments | Posted in Advanced Stats, Announcement, Hockey-Reference.com

Advanced Stats Added to Team Game Finder

Posted by Mike Lynch on November 24, 2014

Users of our Play Index have likely grown accustomed to searching through the Team Game Finder to find things like highest-scoring games or best shooting performances. However, over the years basketball fans (and our users) have grown more statistically savvy and often crave a deeper perspective beyond the raw numbers. For that reason, we have included an advanced box score within our games boxes for some time. Now, we have taken the next step by allowing users to search through these advanced statistics via the Team Game Finder.

To use these tools, you can simply go to the link above and set the parameters you would like for your search. Please note that these advanced stat searches are limited to the era for which we have complete box scores (since 1985-86). Here are some examples:

Please note that cumulative searches utilizing possession-based metrics will differ slightly from some season totals found on team pages and in the team season finder because our box scores have player turnovers, but not team turnovers, which causes slight variations.

Comments Off on Advanced Stats Added to Team Game Finder | Posted in Advanced Stats, Announcement, Basketball-Reference.com, Data, Play Index

Player Season Finder Improvements, Including BPM & VORP

Posted by David Corby on November 13, 2014

Just a note that we've expanded the searchable options in our Player Season Finder this week.

In particular, we've added BPM and VORP to the list of searchable stats, both of which are available going back to the 1973-74 season.  If you don't know what those stats are, you may have missed this recent announcement. Also feel free to weigh in at the discussion on the APBRmetrics forum.

Also, we've added search options by a player's birth state, college, and debut seasons, either in the NBA or ABA. There's also a new option to search by award winners so you can see all seasons by MVP winners, All-NBA selections, Defensive Players of the Year, etc.

If you're new to the site, the Player Season Finder is our most popular database search tool. You can get to it by clicking on 'play-index' in the top navigation menu, then the large 'Player Season Finder' link. It allows you to search for and compare player stats for a season or a player's career (or a span of years). You can also find the number of seasons that match your criteria. As an example, you can find the highest USG% seasons of all timemost career VORP for a player from Duke, or the most points scored in a single postseason.

The new fields are highlighted in red below:

 

psl_new

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

The Relationship Between SRS and NFL Ticket Prices

Posted by TiqIQ Staff on October 20, 2014

The home viewing experience for NFL games is the best it’s ever been. With that, the process of going to a game on Sunday can be a bigger hassle when factoring in all parts of the Fan Cost Index. Some struggles to bring fans to the games lead to things like a fantasy football section in the stadium or poolside cabanas in Jacksonville. On the secondary ticket market, there’s a few different factors that set the level of demand for NFL tickets. Market size will always be one of the biggest factors, as is quality of competition on a game by game basis. One thing the team itself can control to typically keep demand high is presenting a good on field product.

Using the past five seasons of TiqIQ secondary market data and the past five years of team SRS, we can see which teams have the strongest correlation of ticket prices to team success. After running the numbers, 12 teams came out with a correlation of .4 or higher. Another seven teams had a negative correlation of -.4 or below.

The strongest positive correlation came from the Denver Broncos at .99. The average price for Broncos tickets has risen every season since 2010, as has their SRS. In 2010 the Broncos had an SRS of -8.9, an average home price of $120.66 and Kyle Orton at quarterback. This season, the Broncos have an average home price of $339.71 as they are again one of the top teams in the NFL with Peyton Manning. The $339.71 average price is the fifth highest in the league this season.

New Orleans, Washington and Seattle were the only three other teams to have a correlation above .7. Seahawks tickets follow a similar trend to the Broncos. In 2010 the Seahawks had an SRS of -9.4 and a season average on the secondary market below $100. This season, the average price for a home game in Seattle is $398.51, the most expensive price in the league.

Cowboys tickets had the fifth strongest correlation at .69. While the average price for a home game at AT&T Stadium is usually among the top half of the league, the actual average has risen and dipped with the team’s performance. Unsurprisingly, the $260.23 average price at AT&T Stadium is the most expensive over the past five years.

The strongest negative correlation came from teams that have not been particularly good over the past five seasons — the Tennessee Titans, Oakland Raiders, Tampa Bay Buccaneers and Jacksonville Jaguars. The most interesting team in the bottom five is the Atlanta Falcons. The price of Falcons tickets on the secondary market have remained consistent — around a $130 to $150 average price through the years atop the NFC South and the struggles over the past two seasons.

Comments Off on The Relationship Between SRS and NFL Ticket Prices | Posted in Advanced Stats, Announcement, Pro-Football-Reference.com

Play Index Tools Now with Short Surveys & no Ads

Posted by sean on October 8, 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 Basketball-Reference.com
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

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

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