[SanjayM123]

Hi All

I was wondering if you have noticed that N-S hands over a session has more points than E-W hands.

I have been playing Rubber Bridge for more than a month on BBO with few of my friends during this lockdown. I found that generally N-S get better hands.

Though BBO must be having some algorithm to balance the hands, however this is my and some of my friends observation too.

Please do share your observations on this topic.

Thanks

Sanjay Mohan

[Tramticket]

South always has the best hands. Pick up any book or magazine article and you will find that south is invariably the declarer.

[pilowsky]

Except when playing against me. Then I get the best hand. But I play really badly so you will always win. Unless Tramticket is also playing - then it's a 50:50 proposition.

[AL78]

Not my (limited) experience so far. Last time I played I was East and I had some of the best hands in months (average HCP 11.94), and I declared more frequently than normal (six times out of 18). My partner picked up the rubbish (average HCP 8.44).

If there is a bias, it was when playing at my local (physical) club. Averaged around 70% defending frequency over two years. Normally only declared 3-5 times on a 26 board evening. I compiled average HCP strength over all non-novice evenings (easy to do with BridgeWebs) over six months and found no bias in the hand strength by direction, but there was a small negative bias in my hand strength if I only included the hands on the evenings I played. This seemed to be related to a small bias against North and East on the evenings I played, which were the directions I tended to sit, and I noticed that runs of evenings with below average HCP were quite common. Another experienced player who always sits North told me his perception was a bias to picking up sub-par bridge hands.

We'll see what this evening brings.

[barmar]

The only time we change the hands from random dealing is in the "best hand" robot tournaments. Then South (the human) always gets the hand with the most HCP.

[AL78]

Well there certainly seems to have been a bias in my recent BBO sessions. Yesterday evening was the classic Horsham crapness why did I bother turning up. West average HCP 8.72, East average HCP 9.11. Partner and I defended 14 out of 18 hands, we declared twice each. The previous week, average (EW) HCP 8.67 and 9.5. Better the previous week, 10.83 and 9.33. In between all this was one game in the casual section in which I was also on the wrong end of a massive bias, but I don't have the hand records to get the statistics. We'll see what my next game in two weeks brings.

[barmar]

That's the way random numbers are expected to work. Sometimes you have good runs, sometimes you have bad runs.

Making them even out in a single session would require cooking the hands.

[pilowsky]

What you have discovered is the Rosencrantz and Guildenstern phenomenon as reported by Tom Stoppard - The Stoppard convention - as in I have a "Stoppard in all the suits". Here is a link. The odds of a coin always coming up heads or tails. Or if you are always getting the best cards (except of course in a best-hand tournament where coincidentally, you will also be South, and you will also get the worst robot as a partner) are so ludicrously small that if you did then you could reasonably conclude, as did Rosencranz and Guildenstern, that you were dead. Not to be confused with the lesser-known Rosenkranz double or redouble or the reverse Rosenkranz. Either way, you're going to be in trouble.

[AL78]

My local club has run ten BBO sessions. So far there seems to be a bias against East (the direction I sit). Over all 10 boards it is not that large but it is substantial if only the sessions I have played are counted, but the caveat about not concluding anything from very small sample sizes applies.

Average East HCP
11.94
8.44
10
10.83
8.33
8.67
11.11
9.11
9.56
9.83

Six out of ten below average, mean 9.78.

For the sessions I was East:

8.44
10.83
8.67
9.11

Three out of four well below average, mean HCP 9.26. Even on the evening I had better than average hands, my partner copped the worst hands at the table (mean HCP 9.33)

Online bridge has started in a similar way to bridge at the real club. I often used to have evenings at the club when I wondered why I bothered turning up (pass pass pass follow suit follow suit BOTTOM, oh look, no-one else bid the game/slam), and I went home feeling crap rather than having an enjoyable evening. I keep telling myself next time will be better, and that is what I will continue to do whilst playing online. At least the number of boards is lower online so a really poor evening is over quicker.

I seem to have started online bridge at the time of a random poor hands streak. If the deals are fair, this should regress to the mean over the long term (i.e. I won't get a poor set of hands ever session, and a good streak will come up eventually). I will continue to monitor occasionally out of personal interest.

[pescetom]

AL78, on 2020-May-31, 13:59, said:

My local club has run ten BBO sessions. So far there seems to be a bias against East (the direction I sit).

How come you always sit East?

[hrothgar]

AL78, on 2020-May-31, 13:59, said:

Six out of ten below average, mean 9.78.

So, you flipped a coin 10 times, and it came up heads 6 times...

Definitely suspicious...

[pilowsky]

Quite right, there is a 74.3% chance that you are dead.

[AL78]

hrothgar, on 2020-May-31, 14:32, said:

So, you flipped a coin 10 times, and it came up heads 6 times...

Definitely suspicious...

Wow, quoting one sentence out of context, I've never seen that before on an online forum.

You completely ignore what I said about the 10 board bias not being susbtantial and about not inferring much from small sample sizes just to try and imply I am jumping to conclusions about a hand bias. Please don't do this, I've seen it too many times, it is old and it is boring.

[AL78]

pescetom, on 2020-May-31, 14:04, said:

How come you always sit East?

Nothing to do with me, I have no control over the direction I sit. It is me that registers for the session and then invites my partner, would that influence which direction I'm seated?

[johnu]

You need to join the BBO Platinum Patron club which guarantees that you will average at least 11 HCP per hand in any given tournament. If you join the Super Platinum Patron club then you are guaranteed to average at least 12 HCP per hand in any tournament you play. Obviously you have been unlucky to have run up against a lot of players who are Platinum members.

[smerriman]

AL78, on 2020-May-31, 15:48, said:

Wow, quoting one sentence out of context, I've never seen that before on an online forum.

You completely ignore what I said about the 10 board bias not being susbtantial and about not inferring much from small sample sizes just to try and imply I am jumping to conclusions about a hand bias. Please don't do this, I've seen it too many times, it is old and it is boring.

To be fair, you're posting in a thread which was complaining about hand bias, you directly said "there seems to be a bias against East", and "it is substantial if only the sessions I have played were counted". If the purpose of you posting was to demonstrate perfectly normal results and not in any way suggest bias, it was an odd way of going about it.

[pilowsky]

Life is very unfair. Look what I just discovered in wikipedia.
"According to a meta-analysis of 144 studies, totaling 1,787,629 participants, the best estimate for the male to female odds ratio was 1.23, indicating 23% more men are left-handed. 11% of men and 9% of women would be approximately 10% overall, at a 1.22 male to female odds ratio.^{[69][clarification needed]"
This means that if you sit South then the person on the left is definitely at a disadvantage but only - as you will discover later in the same article - if they are a male or a kangaroo.}

[barmar]

AL78, on 2020-May-31, 15:50, said:

Nothing to do with me, I have no control over the direction I sit. It is me that registers for the session and then invites my partner, would that influence which direction I'm seated?

That's strange, I think the inviter always sits West or South.

[barmar]

AL78, on 2020-May-31, 13:59, said:

My local club has run ten BBO sessions.

Does your club use predealt hands from The Common Game, as many clubs have been doing? If so, BBO has nothing to do with the way the hands were dealt.

If they're using BBO-generated hands, we've analyzed them many times and there's no bias.

[gimjan]

AL78, on 2020-May-31, 15:50, said:

Nothing to do with me, I have no control over the direction I sit. It is me that registers for the session and then invites my partner, would that influence which direction I'm seated?

I have tried to sit a different direction by registering and inviting, and alternately waiting for my p to register and invite. Ive even tried signing on to bbo first or last. Nothing changes the fact that I continue to be South. And I guarantee I am NOT getting the best hands! Was hoping to get on this part of the forum and find out how to predetermine my direction. Does anyone know???