The Elo has landed

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Bundy Volume 1
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Re: The Elo has landed

Post by Bundy Volume 1 » Mon Oct 14, 2013 5:41 pm

Alex MM wrote: The main reason everyone uses sport seems to be its ok and people can "use" it.
Not many people at tournaments these days who can use it though. Been dwindling over the past couple of years. So perfect time for Bobby to be awesome and make something new for the (hopeful) next generation of TD's.

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Re: The Elo has landed

Post by robmoss2k » Tue Oct 15, 2013 9:44 am

Alex MM wrote:Any chance you could move the rank column in the events results pages to before the players names?
Done.
Alex MM wrote:Nice work Bobby. Probably worth checking for alternative tournament software before you start designing the whole thing. The main reason everyone uses sport seems to be its ok and people can "use" it.
I've had a check around at some length. Everything else is fairly rubbish to be honest. SPORT in particular - it might be easy to use, but that doesn't make it good.
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Re: The Elo has landed

Post by robmoss2k » Tue Oct 15, 2013 9:45 am

Bundy Volume 1 wrote:Not many people at tournaments these days who can use it though. Been dwindling over the past couple of years. So perfect time for Bobby to be awesome and make something new for the (hopeful) next generation of TD's.
If it works as well as it's supposed to, we shouldn't need a technically competent TD at all, they'll just need to turn up to make decisions...
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Re: The Elo has landed

Post by ybbun » Sat Oct 19, 2013 4:36 pm

How did you match up the players from SPORT files with their existing record in the database? Does it do some automatic name parsing, and are there any manual steps?

One feature that would be really interesting is a player match-up page, i.e. select any two players and see all their results against each other, with total wins and losses. We had this a few years ago on the Britfoos site and it was quite popular - see the comments at http://forum.britfoos.com/forum/viewtop ... 607#p98607

Awesome work by the way!

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Re: The Elo has landed

Post by robmoss2k » Sun Oct 20, 2013 3:18 pm

ybbun wrote:How did you match up the players from SPORT files with their existing record in the database? Does it do some automatic name parsing, and are there any manual steps?
At the moment, it looks for an exact match. If it doesn't find one, it calculates the minimal Levenshtein distance from all the other players in the ranking list and gives that as a hint to match it. There's a manual lookup table into which you can enter this as a shortcut for next time.
ybbun wrote:One feature that would be really interesting is a player match-up page, i.e. select any two players and see all their results against each other, with total wins and losses. We had this a few years ago on the Britfoos site and it was quite popular - see the comments at http://forum.britfoos.com/forum/viewtop ... 607#p98607
I'll have a go. Shouldn't be difficult.
ybbun wrote:Awesome work by the way!
Ta!
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Re: The Elo has landed

Post by Shovo » Mon Oct 21, 2013 10:55 am

This might be pushing it, but do you store enough information to regenerate the charts/group stage tables?

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Re: The Elo has landed

Post by robmoss2k » Mon Oct 21, 2013 12:07 pm

Shovo wrote:This might be pushing it, but do you store enough information to regenerate the charts/group stage tables?
I have thought about this. And the honest answer is, I'm not completely certain.

Group stage tables don't require any knowledge other than the actual results themselves, so these can be worked out on the fly.

In terms of charts... I've got who played who and in what round. Now, for SE, this is simple. A 32 chart will have five rounds, and you can work back from the winner all the way back to the first round without too much difficulty. For DE, things are much more complex and, unfortunately, this is what most events are. A 32 chart has rounds 1, 2, 5 and 8 in the winners' bracket, rounds 3, 4, 6, 7, 9 and 10 in the losers' bracket and round 11 as the final. It isn't difficult to work out algorithmically which round belongs to which half of the draw (first, last, and all rounds where n mod 3 is 2) and as a result I guess it should be perfectly possible to work back from the losers' final in order to determine what the left side of the draw looked like, then fill in round 1, then fill in the winners' side, then drop the final on at the end. I'll look at this at some point, but not before the other stuff. Swiss, however, is just as easy as the groups, but more difficult to write out the results round-by-round, unless we just have a big list - any suggestions? Super Melée I'm not even going to contemplate right now...
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Re: The Elo has landed

Post by The Duke » Wed Oct 23, 2013 11:01 am

i'm still a semi pro right?!!

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Re: The Elo has landed

Post by robmoss2k » Wed Oct 23, 2013 11:58 am

The Duke wrote:i'm still a semi pro right?!!
Not as far as Elo's concerned - too many top 5 finishes!
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Re: The Elo has landed

Post by robmoss2k » Fri Nov 22, 2013 3:41 pm

Elo ratings and results updated post Leonhart Winter Open 2013.
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Re: The Elo has landed

Post by Boris » Fri Nov 22, 2013 5:23 pm

This really is bollux isn't it?

Not that I wouldn't mind being SP/116th, but if you are treating all the events with equal K-value it disadvantages higher-ranked players who compete more often against better-class opponents and less frequently against n00bs.

Obv it is good for the good players (like Les Jones) who hardly ever enter tournaments...

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Re: The Elo has landed

Post by robmoss2k » Fri Nov 22, 2013 6:36 pm

Boris wrote:This really is bollux isn't it?

Not that I wouldn't mind being SP/116th, but if you are treating all the events with equal K-value it disadvantages higher-ranked players who compete more often against better-class opponents and less frequently against n00bs.

Obv it is good for the good players (like Les Jones) who hardly ever enter tournaments...
At the moment the K-value is determined only from how many players compete in the Open events, because I don't have a full list of what category has been assigned to each tournament - if I could have such a list that would be great. The same weightings you apply to each event are applied to the K-value, however, so the impact of things like SS and SD is significantly reduced.

You're 116th because this year you've gone 3-and out in OS at the Leonhart Winter Open, the UKC, the Leonhart Summer Open, SE-2-and-out at the Bar Kick Open, 2-and-out in OD at the Leonhart Winter Open and the Capital Venue Open, 3-and-out at the Leonhart Summer Open, SE-1-and-out at the Bar Kick Open... you've done well in some of the ranked events but not so well in the ones worth the big points, and hence your ranking has dropped significantly. You had 1781 points at the end of 2009, 1719 points at the end of 2012 and currently have 1503 points. For the record, the full list of 49 defeats for you this year, every one of which costs points... some of these players are very good, but - no offence intended to the others - some of them are low-ranked.

Mateusz Mazur
Blagovesta Gerova
Gilles Bloch / Daniel Dubuisson
Jude Fitzgerald / Paul Martin
Gilles Bloch
David Ziemann
Christopher Lyall / Stephen Lyall
Robert Moss / Mike Amsden
Dave Ziemann
Bruce Jassal
Dave Bareham
Paul Martin
Sarah Brice / Alex Millington-Marston
Mariusz Suliga / Grzegorz Zakowski
Chris Bulley / Martyn Harris
Joe Bundy / Donna Walker
Alex Millington-Marston / Jose Oliveira
Vito Migliore / Emily Knox
Sarah Brice / Sam Dawkins
Joe Bundy
Olga Lasecka
Daniel Dubuisson
Tom Willetts
Micheal Ueberbach / Daniel Dubuisson
Maurice Boersma / Roger Klunder
Twan Hermans / Tim Nowottka
Dave Oates
David Ziemann
Tamas Torok / Jose Oliveira
Katarina Krammerova / Matus Holecko
David Ziemann
Vito Migliore
Andrei Russell-Gebbett
Jose Oliveira
Matthew Warr
Louis Tan
Andrew Nubbert / Tom Willetts
Vojtech Zizka / Antonin Kus
Eddie Edwards
Chris Haddon / David Ziemann
Eddie Edwards / Stuart Cree
Stuart Hattle
Jorg Harms
Charly Friessem / Patrick Glocker
Bentivoglio Giuliano / Jorg Harms
Robert Mauer
Robert Mauer
Dave Oates / Brian Harms
Stuart Cree / Stephen Edwards

Rob lost one game all weekend (as far as I can remember) at the LWO and, despite winning all the rest, he's dropped 15 points because of it. But frequently winning keeps him at number one. I've shipped a load of points from losing too many games this weekend just gone too, I'm down about 15 places.
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Re: The Elo has landed

Post by Boris » Fri Nov 22, 2013 7:43 pm

robmoss2k wrote: I've shipped a load of points from losing too many games this weekend just gone too, I'm down about 15 places.
You shipped 125 bonus points at the weekend in the 'official' rankings, for a net loss of 73.6. You could always get a few back at the Rainbow tonight…

The fundamental problem with Elo is that it disincentivises tournament attendance for over-ranked players who, if they simply don't enter, can maintain their high ranking, or players at the bottom who simply fall further and further behind (albeit more slowly with time).

The skills distribution in foosball is pyramidal, not a normal bell-curve so the maths simply doesn't add up.

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Re: The Elo has landed

Post by robmoss2k » Mon Nov 25, 2013 1:46 pm

Boris wrote:The fundamental problem with Elo is that it disincentivises tournament attendance for over-ranked players who, if they simply don't enter, can maintain their high ranking, or players at the bottom who simply fall further and further behind (albeit more slowly with time).
Agreed. These ratings are provided for interest purposes, not as an attempt to replace the official rankings. The intention is to better predict the result of a match for scheduling and simulation purposes, as the current rankings can't predict that.

If these were to become in any way official, and were to be published anywhere, I imagine anyone who had failed to attend a tournament for 12 months (or whatever) would be marked as inactive and would not appear in the list, and anyone who had played fewer than 30 matches would be marked as provisionally ranked.
Boris wrote:The skills distribution in foosball is pyramidal, not a normal bell-curve so the maths simply doesn't add up.
Really? Do you have any evidence for this? Why does the central limit theorem not apply in this case?

I notice that, in the official BFA rankings, Fred has 4085 points and Rob has 8110. And Billy has 3541. And Tony has 3977. Is Rob really nearly an entire Fred better than Fred? Better than Tony and Billy combined? And is Sam Price really the worst foosball player in the country?
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Re: The Elo has landed

Post by Boris » Mon Nov 25, 2013 2:46 pm

I reckon 3 years would be a better 'inactivity' cut off than 12 months.

Of course Rob isn't a whole 'Fred' better than Fred, but he's at least half a 'fred' better than the next best UK player as things currently stand. If we could import all the ITSF results (placings, podiums and bonus points) into the BFA system the overseas players would be more accurately ranked, but it would be a full time admin job to enter these results and keep them updated manually. This is why we use a combination of overseas rankings and WCS history to generate a manageable (2-3 days work per year) starting point for overseas players in our system, and only the overseas results of UK-based players count towards their total. Fred is where he is because our old Tornado rankings which were amalgamated into the current system included all European Tornado tournaments between around 2001 and 2007 so Fred has a strong EuroTornado legacy, to add to his few victories in the UK. On the other hand whenever Rob is beaten he loses shedloads of bonus points (-60 to Mark Balic, -65 to Matty & Callum)

Samantha is also not the worst player in the system, but lost bonus points playing with a semi-pro in an event and hasn't competed since. James Oates was similarly below 900 for a while, for the same reason, but has since worked his way up to Semi-Pro.

I've never said the BFA Rankings are perfect, but they are better than either a simple points-race or a standalone Elo system, taking the best from both systems and mitigating the worst effects of either.

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Re: The Elo has landed

Post by robmoss2k » Mon Nov 25, 2013 4:06 pm

Boris wrote:I reckon 3 years would be a better 'inactivity' cut off than 12 months.
Hence why I said "or whatever" :)
Boris wrote:Samantha is also not the worst player in the system, but lost bonus points playing with a semi-pro in an event and hasn't competed since. James Oates was similarly below 900 for a while, for the same reason, but has since worked his way up to Semi-Pro.
In that case, wouldn't a 900-point floor make sense, considering what the goals of the official ranking system are?
Boris wrote:I've never said the BFA Rankings are perfect, but they are better than either a simple points-race or a standalone Elo system, taking the best from both systems and mitigating the worst effects of either.
And I've never said that Elo ratings should replace the official rankings. I would maintain that they provide a much better method of successfully predicting the outcome of a match, and they exist for two purposes - one, because other people were interested, and two, because I needed a method of successfully predicting the outcome of a match.

Perhaps the ideal way to achieve this combination of "Elo + race" would be to floor the Elo ratings at the start point and add annually-weighted race points onto that rating? Just an idea...

As it happens they'll be down for a bit now because I need to make some fairly serious changes to how things are working. Quite possibly a total rewrite focussed on the tournament management software and I'll re-engineer the SPORT import function and no-match-data-tournament-results import later on. I need to take better care of multi-table events, event weightings, Unicode support for foreign player names and name pronunciation, as well as SMS and e-mail support for match notifications to players and referees.
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Re: The Elo has landed

Post by willhawkes » Mon Nov 25, 2013 4:48 pm

Bobby, I imagine Elo can be used to predict the percentage likelihood of A beating B - would be fun if your software showed that. Not sure how hard it would be to do though.

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Re: The Elo has landed

Post by robmoss2k » Mon Nov 25, 2013 5:37 pm

willhawkes wrote:Bobby, I imagine Elo can be used to predict the percentage likelihood of A beating B - would be fun if your software showed that. Not sure how hard it would be to do though.
Awesome idea...
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Re: The Elo has landed

Post by Boris » Mon Nov 25, 2013 6:07 pm

robmoss2k wrote: Perhaps the ideal way to achieve this combination of "Elo + race" would be to floor the Elo ratings at the start point and add annually-weighted race points onto that rating? Just an idea...
I can see that this could work - if Elo were to replace existing bonus points, i.e. to be positive or negative with a zero sum (e.g. current Elo score minus 1500). The rest of the existing system (place points and RBPs for podium finishes) could remain intact (tweaked if needed). It would mean taking bonus points out of the existing system because they are included in the annual weightings. This would be do-able for the years since the table-specific rankings were combined, but would be too much of an effort to do it for previous years.

I'm sure this is all too simplistic, but I've no objection in principle to a hybrid Elo/points race ranking system if it can be made to work (and easier to administer)

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Re: The Elo has landed

Post by Alex MM » Fri Dec 27, 2013 5:52 pm

Bobby have you tried marking players who have only competed in like one or two events? In other words distinguish between the players that haven't played enough to have an accurate ranking? They do this in other systems. I'd also be interested in seeing what the tables for open etc look like with just the players who are currently ranked semi pro or above now if thats possible.

Have you also distingushed between events with differnt formats. Ie short format games vs long format. As the luck factor plays a much bigger role in short formats.

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