[tournament-org] WhereIsTheBar

TobyManning ptm at tobymanning.co.uk
Tue Oct 2 12:12:01 BST 2018 

Neil:

The purpose of the "bar" is predicated on the premise that the strongest 
players would prefer to play even games not handicap games, even if 
their proability of winning was less than 50%.

Once you accept this hypothesis (which has been well tested), the bar 
follows almost automatically.

In Geoff's example, if the bar is at 5 dan (but all games at the top are 
to be even) then the 5 dan will win the tournament even if he (she) 
loses all 3 games.

To (mis)quote the Organiser's Handbook, without the bar the strongest 
players get an unreasonable (and uneccessary) advantage.

In a tournament with a more normal entry at the top, say 
2d/2d/1d/1d/1d/1k/1k/1k, with the bar at 1 kyu gives all 8 people an 
equal chance of winning the tournament - all they have to do is to win 3 
games. If there was no bar then it would be practically impossible for a 
1 kyu to win the tournament, and the 1 dans would be at a disadvantage 
compared with the 2 dans despite having to play them.

Toby


On 02/10/2018 11:51, Neil Sandford via tournament-org wrote:
>
> The bar has always mystified me. Why should the strongest player(s) be 
> given a less challenging draw than the rest of the field? And why the 
> next-to-strongest be penalised by not being given a handicap when 
> playing another (stronger) player from above the bar?
>
> The purpose of the bar and the mechanism of handicap are two separate 
> discussions. Perhaps we can learn from the golf approach to handicapping?
>
> Players are given an initial handicap (ranking) from assessment based 
> on performance in three games. They can only play in a competition 
> without a handicap by playing off zero (i.e. by being given the same 
> rating as the strongest player in the competition - in Geoff’s case, 5D).
>
> Given that that is unlikely to be very pleasant for either player, 
> there is a provision for assessing three results from games at your 
> own club _/before/_ the tournament. This is most frequently done 
> through a discussion like “You are playing to 8kyu at the club but 
> getting stronger. I suggest you enter as 7kyu”.
>
> Then there is also https://senseis.xmp.net/?RankWorldwideComparison
>
> This attempts to normalise the various rating systems, including the 
> main online servers. I used it in an inter-club competition on 
> Saturday and was at best apprehensive. An AGA 1D was entered at 3kyu, 
> for example. At the end of the day, everyone agreed that the match had 
> been very close (8 games, typically within 10 points). The AGA 1D won 
> both his games. But someone who regularly plays club games at his EGD 
> rating (6kyu) lost both games. Geoff processed the results and only 
> came up with one recommendation (for an unrated player entered as 4kyu):
>
> Beats NG(10.2k -5st) loses RP(5.8k - 2st) So 4k OK but 5k probably 
> more realistic.
>
> Neil
>
> *From:*Gerry Gavigan via tournament-org <tournament-org at lists.britgo.org>
> *Sent:* 01 October 2018 16:35
> *To:* ptm at tobymanning.co.uk
> *Cc:* TobyManning via tournament-org <tournament-org at lists.britgo.org>
> *Subject:* Re: [tournament-org] WhereIsTheBar
>
> That's an extreme interpretation of my comment. I'm not sure why you 
> are inferring "no bar ever"
>
> In this example, as with Cork, there is a sparse entry.
>
> With no handicap the 5 dan will be shooting fish in a barrel and 
> everyone else will be a fish.
>
> My understanding of the McMahon system is that it is designed to give 
> evenly ranked games where possible. In a sparse entry that is not 
> possible and to play without handicaps seems to negate the rating system.
>
> One lemma and two asides
>
> The lemma: if I cannot choose to enter at a grade above my current 
> strength there seems to be a conjugate that I should not be required 
> to play above my current strength (implicit in having a bar in a 
> sparse tournament)
>
> Aside 1: At the EGC I was badly sandbagged by a Chinese player 
> entering his first European tournament way below his actual strength 
> (as he confessed to me after) It's no fun and if one took a simplistic 
> calculation of total cost of attendance divided by number of games 
> inmai tournament, expensive too.
>
>     On 01 October 2018 at 15:57 ptm at tobymanning.co.uk
>     <mailto:ptm at tobymanning.co.uk> wrote:
>
>     Gerry:
>
>     Are you seriously saying there should NEVER be a bar, or are you
>     saying that in this extreme case, the bar should be at 5 dan?
>
>     Toby
>
>     On 2018-10-01 14:40, Gerry Gavigan wrote:
>
>         As set it sounds to me, on behalf of all of those several
>         stones weaker than the 5 dan, that there should not be a bar
>
>         By any measure the 5 dan has already won.
>
>         As a 1 kyu (I wish) without a handicap I am going to have a
>         rubbish time.
>
>         The purity of some tournament protocol should be secondary
>
>         If the tournament police are going to insist on a bar the TD
>         should consider bribing the 5 dan not to enter for the greater
>         good and encouraging the potential lambs-to-the-slaughter to
>         turn up next year.
>
>             On 01 October 2018 at 12:20 TobyManning via tournament-org
>             < tournament-org at lists.britgo.org
>             <mailto:tournament-org at lists.britgo.org>> wrote:
>
>
>             I set it at 1 kyu, but if an organiser set it at  2kyu I
>             would not complain.
>
>             Setting it at 3 kyu would be wrong.
>
>             Toby
>
>
>             On 01/10/2018 11:45, Geoff Kaniuk via tournament-org wrote:
>
>                 You have just registered your last player who happens
>                 to be 1d and
>                 people are waiting impatiently,  wanting to get on
>                 with your 3 round
>                 McMahon tournament.
>
>                 You are now faced with with the problem of where to
>                 set the the bar.
>                 Suppose in this tournament the top players are:
>
>                 5d 1d 1d 1k 1k 2k 2k 3k 3k 4k 4k 5k .....
>
>                 Assuming all players enter at a realistic grade, where
>                 would you set
>                 the bar?
>
>                 It would be interesting to see your instinctive
>                 answer, rather than
>                 consulting the Tournament Organiser's Handbook.
>
>
>
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>
>
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