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Onside Kicks Updated in Play Finder

Posted by Mike on December 7, 2012

Since there's been talk lately of eliminating kickoffs altogether and moving to a "4th and 15"-style play I've updated the Play Finder tool to include onside kick success and percentage in the kicker table. For instance, from 2000-2012 we show 757 onside kicks, with 149 of those recovered by the kicking team for a 19.7% success rate. Contrast that to all 4th and 15 plays since 2000, where we show 21 out of 93 plays converted to either first downs or touchdowns at a 22.6% success rate. Since 4th and 15 attempts are generally a desperation situation against a team that may be playing in a prevent defense (and thus willing to give up the 15 yards in order to keep the offense out of the end zone at all costs), let's look at conversion rates on 3rd and 15: we show a 15.7% success rate in converting those.

Of course one of the primary benefits of the onside kick is the "surprise" onside kick. Broadly defining that as any onside kick NOT in the 4th quarter we see those recovered by the kicking team at a 47.5% rate (though only attempted 158 times in 3381 total games, roughly once every 21.4 games).

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

Add Your Blog Posts to PFR Player Pages

Posted by Neil on December 3, 2012

PFR Player Name Linker / Add your Site to our Player Newsfeeds

With the 2012 regular season drawing down to its final quarter, here's a reminder that we have newsfeeds on the PFR player pages, showing the latest player news from KFFL, injury reports and links to relevant PFR blog posts. If you have a blog or website with an RSS feed you can add your site to relevant player pages as well. Our Player Linker Tool will take your blog posts as you've written them and run them through a program and add links to PFR player pages where appropriate. So while you don't have the resource to create your own player pages for your site, you can treat us as your site's statistics partner, linking Eli Manning's name to our stats or any player all the way back to Y.A. Tittle and Otto Graham.

If the links then appear in your rss feed and you let us know to look for them, we'll pull them out of your feed and then link back to you from Eli's page, or Otto Graham's or whomever you link to.

If you help your users find our great content, we'll help our users find yours. And best of all it is all automated except for one click of an easy-to-install bookmarklet. Check the Player Newsfeeds page for details. This link share will also work for tables you share using the SHARE tooltip found above every stats table on the site.

1 Comment | Posted in Announcement, CFB at Sports Reference, Features, Linker, Pro-Football-Reference.com

2013 NFL Hall of Fame Semifinalists Announced

Posted by Mike on November 30, 2012

The 2013 NFL Hall of Fame ballot is now here, complete with career stats and AV.

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

Playoff Seedings Now Up!

Posted by Mike on November 18, 2012

We now have current NFL playoff seedings (after some extensive tinkering and constant referencing of the NFL's playoff tiebreaking procedures) which we will keep up-to-date from week to week, including the reason one team may be chosen above another with the same record. Look for it to be updated after each game day and keep an eye on your team's chances!

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

College Football Box Scores

Posted by Neil on November 13, 2012

Get the latest college football box scores by going to our Boxscore section of the site. The default view will be the most recent scores from the current season, but you can also find them for every year going back to the 2000 season.

Comments Off | Posted in Announcement, CFB at Sports Reference, Pro-Football-Reference.com

Automatic Player Linker Tutorial (Video)

Posted by Neil on November 9, 2012

Here's an updated video to describe the Sports-Reference Automatic Player Linker tools, which are now available for college football & basketball and hockey:

Also, here's the old tutorial video:

As always, if you want to be included in the program, just email me with the following information:

  • the name of your site to appear in the feed (at most 25 characters)
  • the url for your rss feed (must be a full feed)
  • a contact e-mail address
  • the url of an example page with our links in place

6 Comments | Posted in Announcement, Baseball-Reference.com, Basketball-Reference.com, CBB at Sports Reference, CFB at Sports Reference, Features, Hockey-Reference.com, Linker, Pro-Football-Reference.com

Field and Stadium Types Added to Team Game Finder

Posted by Mike on November 8, 2012

We've just added field type (grass or artificial) and stadium type (domed, open, or retractable roof) to the team game finder tool, which you can use to learn that Oakland is 1-7 in road games on turf in the past 5 years or the Packers are 18-12 in domes since 2002. In addition, we are trying to hunt down data indicating whether a retractable roof stadium was open or closed on gameday -- if you have any source of that data, let us know in the comments.

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

PFR Game Score Finder

Posted by Neil on November 5, 2012

We don't know what tonight's game will hold, but it just might end with an historically-unique final score. If so, as a Pro-Football-Reference user you'll know first because you can run a search on any combination of final scores to see how often they've occurred all-time.

Using the main table on this page, and clicking the "count" column header to sort by he number of instances in the database, you can find the rarest and most common scores in pro football history. You might be surprised to see the number of combinations that have taken place just once, running the gamut from 66-0 blowouts to brutal 5-3 affairs. And at the other end of the spectrum, 20-17 is by far the most common all-time final score.

Play around with the tool for a while, and you'll always know where to find an answer when somebody asks, "how often does this score happen?"

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

New Vegas & game time features on Team Game Finder

Posted by Mike on November 2, 2012

Spending a lazy Friday morning at work? No fear, we've put a couple of new features up on the Team Game Finder tool.

First off is the addition of Vegas betting lines (from 1978 to now) to the additional search criteria selector, with which you can find games in the past 5 years in which a team was favored by more than 10 points or 17+ point underdogs in the last 30 years. We also have Over/Under lines, with which you can find all Patriots games since 2002 with an O/U greater than 50.

Next, we've added game time and time zone selectors to the filter criteria, with which you can find that the Bengals have a .700 record since 2002 in games played at 4pm in the Eastern time zone or that the Green Bay Packers have the best record in the last 15 years in road games on the West Coast.

1 Comment | Posted in Features, Pro-Football-Reference.com

Estimating NFL Win Probabilities for Matchups Between Teams of Various Records

Posted by Neil on October 30, 2012

WARNING: Math post.

PFR user Brad emailed over the weekend with an interesting question:

"Wondering if you've ever tracked or how it would be possible to find records vs. records statistics....for instance a 3-4 team vs. a 5-2 team...which record wins how often? but for every record matchup in every week."

That's a cool concept, and one that I could answer historically with a query when I get the time. But in the meantime, here's what I believe is a valid way to estimate that probability...

  1. Add eleven games of .500 ball to the team's current record (at any point in the season). So if a team is 3-4, their "true" wpct talent is (3 + 5.5) / (7 + 11) = .472. If their opponent is 5-2, it would be (5 + 5.5) / (7 + 11) = .583.
  2. Use the following equation to estimate the probability of Team A beating Team B at a neutral site:

    p(Team A Win) = Team A true_win% *(1 - Team B true_win%)/(Team A true_win% * (1 - Team B true_win%) + (1 - Team A true_win%) * Team B true_win%)

  3. You can even factor in home-field advantage like so:

    p(Team A Win) = ((Team A true_win%) * (1 - Team B true_win%) * HFA)/((Team A true_win%) * (1 - Team B true_win%) * HFA +(1 - Team A true_win%) * (Team B true_win%) * (1 - HFA))

    In the NFL, home teams win roughly 57% of the time, so HFA = 0.57.

This means in Brad's hypothetical matchup of a 5-2 team vs. a 3-4 team, we would expect the 5-2 team to win .583 *(1 - .472)/(.583 * (1 - .472) + (1 - .583) * .472) = 61% of the time at a neutral site.

Really Technical Stuff:

Now, you may be wondering where I came up with the "add 11 games of .500 ball" part. That comes from this Tangotiger post about true talent levels for sports leagues.

Since the NFL expanded to 32 teams in 2002, the yearly standard deviation of team winning percentage is, on average, 0.195. This means var(observed) = 0.195^2 = 0.038. The random standard deviation of NFL records in a 16-game season would be sqrt(0.5*0.5/16) = 0.125, meaning var(random) = 0.125^2 = 0.016.

var(true) = var(observed) - var(random), so in this case var(true) = 0.038 - 0.016 = 0.022. The square root of 0.022 is 0.15, so 0.15 is stdev(true), the standard deviation of true winning percentage talent in the current NFL.

Armed with that number, we can calculate the number of games a season would need to contain in order for var(true) to equal var(random) using:

0.25/stdev(true)^2

In the NFL, that number is 11 (more accurately, it's 11.1583, but it's easier to just use 11). So when you want to regress an NFL team's W-L record to the mean, at any point during the season, take eleven games of .500 ball (5.5-5.5), and add them to the actual record. This will give you the best estimate of the team's "true" winning percentage talent going forward.

That's why you use the "true" wpct number to plug into Bill James' log5 formula (see step 2 above), instead of the teams' actual winning percentages. Even a 16-0 team doesn't have a 100% probability of winning going forward -- instead, their expected true wpct talent is something like (16 + 5.5) / (16 + 11) = .796.

(For more info, see this post, and for a proof of this method, read what Phil Birnbaum wrote in 2011.)

3 Comments | Posted in Announcement, Pro-Football-Reference.com, Stat Questions

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