Sources of variance in Bridge

[hrothgar]

You might also find it useful to take a look at two dimensional space filling designs

 

Not the same as a PRNG, however, a bunch of the same issues are involved and its easy to visualize what is taking place

[blackshoe]

I’m not a fast player…I used to be, then I learned (from a very good player) to slow down…and to THINK.

"Slow is smooth, smooth is fast". :-)

[helene_t]

I just pulled some variance components out of my sleeve:

 

Total points for NS, single board across a somewhat heterogenous field (say a typical club night):

- Strength of the NS cards: 60%

- Randomness and skills: 40%

 

Mathchpoints for NS, single board across a somewhat heterogenous field (say a typical club night):

- Skills of NS relative to EW: 30%

- Skills of the NS field relative to the EW field: 5% (but this will depend on the size of the field)

- Which random mistakes happen to get punished (or awarded!) on this board: 45%

- Luck in toss-up situations: 13%

- Systems issues (for example some boards are good for the weak NT pairs): 5%

- Ethics (use of UI, incomplete disclosure): 2%

 

Maybe the black/white distinction between the 3rd and the 4th point is problematic. If a declarer gets lucky with a 49% guess for finding the queen it is technically an award for a mistake but not distinguishable from a toss-up situation, as the probabilities are usually a bit subjective.

[pilowsky]

Possibly the problem posed by the possum doesn't relate to variance associated with dealing the cards (an issue 'dealt' with many times here).

Suppose you sit down in an average tournament with an average partner on an average day.

What is it in Bridge that causes such enormous variance that, say compared to chess or go or football, the pair that is known to be excellent doesn't necessarily defeat a weak pair?

 

Clearly, many factors are in play.

Tiredness of a person could be major source of variance.

Unexpected gifts another.

 

As noted above randomness doesn't mean blandness.

So one pair could get lucky and find a sequence of deals that particularly suit their style.

In this way Bridge seems to have many more non-skill uncontrollable elements than many other games.

 

One advantage (there are quite a few) of the robot game is that many of these sources of variance are stabilised.