Quote:
Originally Posted by Chasqui
Hi Mason , a few questions:
What value for standard deviation are you using for this calculation? What did you use to determine this standard deviation? Have you compared it to online databases?
In my experience playing SoCal 20/40 for several years full time, it's not unlikely to go on a 9k downswing in under 2 years. Not only I have my own data point but a few from winners in the game who play many hours.
As another data point. I had $3000 sessions when I used to play long hours of 8-16 full kill in super action games.
Something doesn't add up, my guess is the standard deviation you are using, or the RoR you are defining as "ok" for a full time professional with normal living expenses.
Hi Chasqui:
First off, I use
BR = [(9)(Var)]/[(4)(WR)]
for the bankroll formula. This formula was first given in my book
Poker Essays, published in 1991, but is actually derived from my book
Gambling Theory and Other Topics which was first published in 1987. Note that Var is the variance which is the standard deviation squared and WR is the estimated win rate. Also, how to estimate your standard deviation, using the maximum likelihood estimator is given in the
Gambling Theory book.
As for my numbers, I'm using 1 big bet per hour (which I think is doable at $20-$40 but too high for most $40-$80 games and 9 big bets for the hourly standard deviation. This gives a required bankroll of 182 big bets. Then this should be increased a little to account for things like you don't have the exact same win rate and standard deviation every time you play. (This is equivalent from a statistical point of view of reducing the sample size by a little bit.) Thus 200 big bets (or perhaps a little more) should be enough for a safe bankroll using this criterion.
Notice your $9,000 downswing is 225 big bets so you're not far off my numbers.
A couple of quick points. Two errors I see from many of today's players is that they open too loosely from early position and three bet too loosely. This will add plays that lower your expectation a little but will increase your standard deviation by a lot. Lowering your expectation will increase your required bankroll (in this case a little) and increasing your standard deviation will increase your required bankroll (in this case a lot).
Also, as a aside, it seems like I'm reading many posts like yours recently where the poster seems to be unaware of the formula above and where it comes from and how it's derived. All of this has been around for many years.
Best wishes,
Mason