Sports Reference Blog

SV%+ Calculation Poll

Posted by Neil on October 10, 2013

In case you missed it yesterday, we rolled out a couple of new goaltending stats for the 2014 season -- Save Percentage+ and Goals Saved Above Average. Overnight we got some feedback about SV%+ in particular, and the structure of having 1 minus the goalie's own SV% in the denominator of the formula. Right now, we are measuring the rate at which the league allowed more goals than the player, where 100 = average. So in the case of a 133 SV%+, the league's rate of goals allowed per shot would be 33% higher than the player's rate.

There are other alternatives. If we re-arrange the formula so that 1 minus the league SV% is in the denominator, we would be measuring the rate at which the player allowed fewer goals than the league. (Because of the nature of division, this is an important distinction from the definition in the previous paragraph.) If we tweak the formula in this direction, there are 2 options: we can compute a "minus" type of stat in which lower numbers are better, or we can stick with the "plus" style familiar to all from baseball's OPS+ and ERA+. The former would represent a goalie who allows 33% fewer goals than the league as a 67 (remember, lower is better); the latter would represent that as a 133.

(If any of this sounds familiar, it's because this battle was fought at Baseball-Reference 3 years ago and continues to rage in some corners of the internet to this day.)

As is the case sometimes in this business, there is no "right answer" here, but rather a matter of preference. For instance, we've long assumed users would find it counterintuitive to have a rate stat where lower numbers = better performance, but maybe that's not true. I'm interested in opinions on this, so let your voice be heard in the following poll -- which format do you prefer? Or do you care at all? I can't promise the poll-winning format will be what we eventually stick with, but I'd like to know what people think.

Posted in Announcement,, Polls, Stat Questions | 7 Comments »

Save Percentage+ and Goals Saved Above Average

Posted by Mike on October 9, 2013

Today on Hockey Reference we're rolling out two new stats for goalie pages: Adjusted Save Percentage (SV%+) and Goals Saved Above Average (GSAA). First, you can check Broad Street Hockey for a great explanation of adjusted save percentage and goals saved, but for a simple look, consider the 2012-13 NHL season. League-wide, there were 41,827 shots overall and 3,684 goals scored, for a goals against average of 8.81%. Vezina Trophy winner Sergei Bobrovsky had a goals against average of 6.87% -- 29% better than league average, giving him a SV%+ of 129. Taking that 29% better performance into account combined with the number of shots he faced, we say he saved 21.48 goals more than an average goalie would have, given equal playing time.

These stats are especially helpful for comparing goalies across eras: Patrick Roy led the league in save percentage in the 1991-92 season with a .914 SV%; in the 2012-2013 season that would have placed him as the 26th best goalie between Ben Scrivens and Jonas Hiller. However, we can look at his SV%+ of 130 for that year and see that he was actually 30% better than the league average at stopping goals -- better than Bobrovsky, even.

Note that SV%+ has a minimum requirement of 4 shots faced per team game, so that we don't have goalies who stopped 7 of 7 shots faced in their single period played skewing the results. These stats are now up for goalies as far back as the 1983-84 season (the first year we have shots against data for the NHL), and for the entirety of the WHA (1972-1979), and will be updated throughout the year.

Posted in Announcement, | 5 Comments »

Win Probability Explained

Posted by Mike on October 7, 2013

You may have seen our in-game Tweets and the win probability graphs on our box score pages -- we now have a detailed explanation of the win probability methodology from Neil Paine if you're curious how it works.

Posted in Advanced Stats, Announcement, | 1 Comment »

Team and Yearly Splits

Posted by Mike on October 3, 2013

Using the play-by-play data that powers our play finder, I've built detailed season split pages for each team on offense and defense, as well as league total splits and league average splits for the year. Now you can compare your team's performance by field position to the league's, or see which team is best in the fourth quarter. If you can think of a situation you want to see that's not covered here, leave a comment & we'll see what we can do.

Posted in Announcement, | 2 Comments »

P-F-R Position Abbreviation Glossary

Posted by Neil on October 1, 2013

We often get emails about some of the more... let's say "esoteric" positional abbreviations in the P-F-R database (the most confusing of which date back to the earliest days of professional football). Here's a handy guide in case you ever get stuck wondering what in the world some of these positions are:

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Posted in Announcement, FAQ,, Stat Questions, Trivia | Comments Off on P-F-R Position Abbreviation Glossary

2013 Sim Scores Updated –

Posted by admin on September 30, 2013

Mike Trout Statistics and History -

Ignoring for the moment there is another game to play tonight, I ran the sim scores this afternoon and uploaded the pages. I'll get around to rerunning them tomorrow, probably for the Rays and Rangers. Here is our explanation of sim scores.

Posted in Advanced Stats, Announcement, | 1 Comment »

Pro Links on College Players

Posted by Mike on September 25, 2013

In the interest of unifying our college football and pro football sites a bit better, we've added draft information and links to pro stats for college players from Karim Abdul-Jabbar to Eric Zeier.

Posted in Announcement, CFB at Sports Reference, | Comments Off on Pro Links on College Players

Trivialities – BA, OBP, SLG on PI Game Finder & New Split

Posted by admin on September 20, 2013

Batting Game Finder -- -

The batting game finder now has criteria and sort options for BA, SLG and OBP, so you can do things like find out easily how often Ted Williams when 3 for 3 or better (37 times) or how many times Barry Bonds reached base in every PA of a game (no min.) 153 times.

The other things is we will be adding this weekend (should show up Sat. and just for 2013) a split for the player results in PA's where they swung at the first pitch and PA's where they took the first pitch. We'll do it for our historical data when we run the whole shebang at the end of the season.

Posted in Announcement, | 1 Comment »

Team Owners & Executives

Posted by Mike on September 20, 2013

Thanks to the research of Neil Paine, we now have lists of team executives and owners dating back to 1936, a page for each executive, and owner/executive lists for each team. These lists are complete for active franchises, though we have partial data for defunct franchises as well.

Posted in Announcement, | Comments Off on Team Owners & Executives

Gain Superpowers! Watch our Player Page How-to Video.

Posted by admin on September 20, 2013

Sports Reference Videos - YouTube.

One of the challenges of a site this big and dense is making users aware of what they can do. To accomplish this we are working on a series of how-to videos for various site features. Our first video is an overview of everything you can do from our player pages.
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Posted in Announcement, | Comments Off on Gain Superpowers! Watch our Player Page How-to Video.