Some interesting statistics on ROI variance

#1 11-08-2005, 02:47 PM

This is an example intended to help anyone who does not fully understand how significant variance can be over large numbers of games. I know it is talked about ad nauseum here, but it still seems to be underestimated by many and since it is probably the single most important concept for any player who wants to take their game seriously to understand, I though I would share some interesting statistics.

In an attempt to understand what a difference a weekend can make, I played at nearly identical times over the past two weekends:

Last weeked
------------
SNGs: 700
ROI: 25.7%
Variance within any given 100-game sample: 61%

This weekend
------------
SNGs: 750
ROI: 3.4%
Variance within any given 100-game sample: 76%

After studying the differences between the two sets it appears that the main reason for the difference was that I was getting lucky in the early game with a significant # of double-ups and large pots so that I was coming into the middle-game with far mor chips than this weekend, where I was also underperforming on the bubble (even in relation to my low chipstack).

Obviously this is an extreme example, but the point being that to many players 750 SNGs represents many weeks (or even months) of playing and that even 1,000 sngs is truly insignificant in terms of ROI. Over my last 10,000 SNGs I have found that any given sample of 1,000 tournaments has a variance of roughly 17%. I potentially play a style that aggravates the variance a bit, but in other ways I am less prone than most.

So what I find the most difficult about poker is when making adjustments to our game, how do we determine whether or not these new "plays" or "styles" actually gave us any improvement? I think it is actually impossible in the short-term (at least with the resources most of us have). For me this is the reason why poker is both so compelling and so hideously aggravating!

-asimo

dedicated to freeing the Variance Slaves!

citanul · #2 11-08-2005, 02:48 PM

what does:

[ QUOTE ]
Variance within any given 100-game sample

[/ QUOTE ]

mean?

c

tigerite · #3 11-08-2005, 02:49 PM

You played 700-750 SNGs in one weekend?! Even 10-tabling continuously that's impossible.

downtown · #4 11-08-2005, 02:51 PM

So you play 700-750 SNGs a weekend?

Do you dream of electric sheep?

Shilly · #5 11-08-2005, 02:51 PM

What level is this at?

downtown · #6 11-08-2005, 02:51 PM

[ QUOTE ]
You played 700-750 SNGs in one weekend?! Even 10-tabling continuously that's impossible.

[/ QUOTE ]

At least I'm not going crazy, I was thinking the same thing.

citanul · #7 11-08-2005, 02:54 PM

[ QUOTE ]
You played 700-750 SNGs in one weekend?! Even 10-tabling continuously that's impossible.

[/ QUOTE ]

10 tabling -> ~14 an hour?
700 sngs at 14 an hour = 50 hours.

very doable. [img]/images/graemlins/smile.gif[/img] and playing 20 tables at once makes it a laugher!

c

tigerite · #8 11-08-2005, 02:55 PM

Barely, unless he didn't sleep, or is including Friday night.

20-tabling, sure, but I don't think there's many people that do that, other than raptor.

eniven · #9 11-08-2005, 02:57 PM

Wow, that's an interesting post. Thanks.

#10 11-08-2005, 03:13 PM

[ QUOTE ]
what does:

[ QUOTE ]
Variance within any given 100-game sample

[/ QUOTE ]

mean?

c

[/ QUOTE ]

This just means that if you take any sample of 100 consecutive tournaments from within the 700 (or 750) the number is the differrence between the group with the highest ROI and lowest ROI.

For example, in the 750-sng weekend there was a run of 100 tournies with an ROI of +41%, and a 100-sng run with an ROI of -35%, thus the variance within any sample of 100 sngs was 76%