Statistical Aggregation of WFTDA Sanctioned Roller Derby

FTS Top Rankings





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Recent Bouts

Quick Stats

Total Leagues 98
Total Bouts 1073
Official Bouts 940 from 07/23/05 to 08/28/10
Unofficial Bouts 85
Upcoming Bouts 48
Avg Score/Bout 106
Highest Scoring Bouts
(combined scores)
446
04/10/10 (PPDD)420 vs (SHDG)26
431
03/14/10 (CCRG)409 vs (RCR)22
410
11/18/05 (MNRG)237 vs (CRG)173
409
02/28/10 (JCRG)329 vs (HPRD)80
Lowest Scoring Bouts
(combined scores)
112
04/19/08 (NRG)63 vs (BCB)49
118
05/03/08 (FWDG)55 vs (BCB)63
118
11/18/07 (PRG)62 vs (BADG)56
Largest Blowouts
(difference of scores)
394
04/10/10 (PPDD)420 vs (SHDG)26
387
03/14/10 (CCRG)409 vs (RCR)22
377
04/17/10 (DRD)391 vs (FCGGD)14
328
06/12/10 (KCRW)353 vs (NWA)25
Closest Bouts
(difference of scores)
1
03/21/10 (PRD)110 vs (CRG)111
Avg Penalties/Team/Bout 72
Highest Combined
Penalties/Bout*
301
02/16/07 (TXRG)93 vs (RCRG)105
234
07/21/07 (Rose)111 vs (RMRG)74
231
09/29/07 (WCR)56 vs (TXRG)108
Lowest Combined
Penalties/Bout*
47
06/17/07 (HRD)197 vs (ACRG)79
48
01/20/07 (DDD)117 vs (PPDD)53
56
01/07/06 (SCRG)108 vs (DCD)51
* Penalty metrics are incomplete. There are a fair amount of bouts that are missing penalty information. Let us know if you can help fill them in.

Site News

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Export Our Database

Put up a new section that allows anyone to download a snapshot of our database.  There’s two sections: Bout Data, and Team Data, both of which can be downloaded in .CSV format.

Just wanted to make it easy for anyone to play with the numbers - have at it!

It’s in the Tools section under Export Data.

posted by Aaron on February 5th, 2009

Tournament Rankings & Custom Compare

Last week we made updates to the rankings that include the results of the 2008 tournament season.  For each tournament (2 regionals, and 1 championship), 1st - 4th place are determined naturally but the remaining places are up for debate.  We used the same technique that we used last year for the 2007 tournament season: combining elements of the FTS ranking system, and the logic that teams should be ranked relative to their opponent’s placement in the tournament.  Scintillating I know; you can read about how we came to that using last year’s tournament season.

Since we’re rather late on the tournament update (sorry!), I put together a consolation tool: Custom Ranking Comparisons.  It basically lets you compare any two rankings on this site (FTS, WFTDA, or FTS Variation) from any day in history.

  • You could use it as a time machine and have it look up the FTS rankings on any day.  You could use the second column to compare that history with today or any other day.
  • You could use it to put the ranking variations in perspective by comparing them to the standard FTS algorithm.
  • You could use it to see where the WFTDA ranks correlate with the FTS ranks.
posted by Aaron on January 28th, 2009

Ranking Variations

I never thought it would take us this long to release these (it’s been six months of FTS now!).  It was something we intended on rolling out immediately because I think it demonstrates nicely what’s subjective about computerized ranking.  It also offers some different perspectives on rankings, and maybe there’s something here that is closer to how you think teams should be ranked.  Such things like full blowouts, just wins/losses, no tournaments, and the daily sampled bout decay are all being experimented with over there.  See the new Ranking Variations page.

It should be noted that these variations are isolated changes to the standard FTS ranks.  I believe that if you wanted to pursue the philosophy of one of these variants as a ranking system, there’s potentially more to be done to make the system more robust (or starting from scratch on a system that foregrounds that concept).  For instance, it’s interesting to see what the FTS system looks like if you take out extra tournament bonuses.  But if we wanted to seriously pursue a system that ignored tournament results, we would probably tweak the way other parts of the system work.  Since the FTS system relies on tournament reputation for some amount of it’s weighting, simply removing it in this variation produces some illogical results because a significant balancing element is missing.

But knowing that, I think the variations are helpful.  For now they may just serve a perspective relative to the standard FTS ranks, but maybe in the future, rebuilding some of these philosophies from the ground up could be a way to go.

posted by Aaron on August 2nd, 2008

Tucson Bout

Just wanted to give a heads up that Tucson’s drop 27 points in Today’s Ranks is a combination of two things that happened this weekend - their loss to Windy City, and the disappearance of a win to Madison from one year ago.  If you’ve been following along since we released the new ranking system, you’ve noticed teams moving despite having not played in the last week.  This is a bout from exactly a year ago that just popped outside of our view (full explanation here).  Today (Monday), it actually looks pretty clean.  Only Tucson and Madison move in this way, and everyone else had a bout this weekend.

We’re working on some ways to make this a lot clearer - to differentiate between movement from recent bouts, movement from disappearing bouts, and today’s extra confusing scenario where both things happened.  Until then, watch out for it!

posted by Aaron on July 14th, 2008

RankWrench: Custom Ranking Tool

Attention WFTDA voters!  Recent derby craziness making you fear your looming task?  Maybe we can help.  We’ve written a tool that lets you drag-and-drop your own custom ranks, quickly bring up recent bouts, and analyze your ranks for logical errors.  Choose last quarter’s WFTDA ranks (or any other preset) for a starting place if you like.  Then Export the plain text to your people and call it a day!  Of course, non-WFTDA voters are welcome to play with it too.

Let us know how it works for you, or if you have ideas for comparing teams, and coming up with awesomely accurate WFTDA ranks!

Note: Older browsers or computers may have some trouble with the drag/drop.  Firefox 3 should work without a hitch though.

posted by Aaron on June 30th, 2008

New Ranking System

The updated ranking system is finally done and online today.
These are the major changes, which I’ll document more fully in the coming days:

  • One Year Bout Decay:  Bouts played longer than 365 days from today’s date are ignored.
  • Re-seeding with all bout data:  All bouts are re-run starting from 2005.  Even though these are outside of the bout decay, they can effect later games by propagating down and informing what an opponent’s skill may be.  This doubles the dataset with an extra year and a half of data, as previously we were only looking at 2007 to now.
  • New Tournament Results:  We calculated all tournament placements equally and by our own method Seeding By Outgoing Ranks (fully documented over here)
  • Tournament Decay and Weighting:  This had never been an issue before, but is necessary when reseeding from 2005: Reputation from a tournament season lasts until the next tournament replaces it.  Another way of saying this is the national champions remain the national champions until they are dethroned.  This effect already existed, but the system now knows what to do with historical tournaments, and the upcoming tournament season.  Also the tournament bonus is weighted less overall, which is one factor that makes the rankings more mobile in the upper ranks.
  • Tightened Blowout Adjustment:  Tightened up this curve a bit so the largest blowouts are even more equivalent to normal size blowouts.  Or to put it another way, bigger blowouts mean less.
  • Low Participators as Opponents:  When we introduced what we affectionately refer to as the Kiddie Pool, we didn’t have a sound method of addressing what happens when a team plays a low participator.  The new rule is that if you are in the Kiddie Pool as a newbie (2 or less bouts), your calculated skill to an opponent is the worst rating in that quarter’s ranks.  If you are in the Kiddie Pool as a veteran (more than 2 bouts ever, but bout decay gives you only 1-2 in the last year), your calculated opponent skill is not penalized.

If you’ve been following along things will look a lot different.   Teams are in general a little more mobile (this was one of our goals), so if you’re used to a certain outcome generally giving +5, you’ll probably find a new set of norms.

There is one major caveat that I’d like to point out in using a bout decay.  Since last year’s regionals happened 6 months apart (!), Eastern division teams get their tournament bouts counted, while Western division teams do not (because the 2007 Dust Devil is more than one year ago).  The affect is Eastern teams get pushed up a lot more than Western teams (at least those that had nice outcomes at Regionals).  Rat City probably feels that effect the most and drops a few places for it.  We debated whether we should artificially include Dust Devil games to even up the top ranks, but this just feels like ignoring the reality of the situation, and the fact that this upcoming season fixes the issue.  At the very least, you can use the filters to see Western and Eastern compared amongst themselves.

If you’d like to know about the gritty details of these decisions, keep your eye on the Development Blog (and subscribe if you like).  I’ll be unloading the hows and whys of each of these things over the next several days, plus a bunch of observations we’ve come to on how these can be be better, and where to go from here.

Edit: More posts from the Dev Blog

posted by Aaron on June 26th, 2008

Add Bouts

New feature in FTS land: Add/Edit Bouts*. It’s now super easy to keep us updated with bout information, whether it be a bout that ended 20 minutes ago, or loading us up with bouts from two years ago. We’ve gotten a lot of info from folks over the months via the feedback form, but we wanted to make it even easier for you (and us). Please verify your team’s history if you haven’t already done so, otherwise keep doing what you’re doing, and this form should make the process much more streamlined. Also feel free to ask us if you’re not sure if a bout belongs on here or not. You can see the basic outline of the matter here.

*[Actually the Edit Bouts part is just a tease - that will be for another day. Send existing errors the old fashioned way.]

posted by Aaron on June 11th, 2008