End profit is not the answer!

Discussion in 'General' started by Sonny, Oct 1, 2007.

  1. Sonny

    Sonny Well-Known Member

    Many people choose to test their betting system through actual play instead of using computer simulations. They feel that actual results will give them a better idea of how well their system really works. They think that as long as their system continues to win money that is must be effective. Unfortunately, this can not only lead to wildly unreliable results but it can also be completely inaccurate if the numbers are misunderstood.

    For example, let’s say our friend Smitty has a new system he thinks might work. He decides to play against a coin flip and see if his system can get an advantage. He bets $1 per flip and after 10 flips he manages to win $4. He is very happy, but he also knows that it could just be luck so he decides to play 10,000 flips before making up his mind.

    After 100 flips he is ahead $10. Things are looking good, but he isn’t celebrating just yet. After 1,000 flips he is ahead by $30 and his system still seems to be working. After the final 10,000th flip he finds himself ahead by $100. His system has been consistently winning money this whole time. He is now completely convinced that his system is a winner. He goes on all the blackjack websites and posts that he has an amazing system that gives you a small advantage over the house and is much easier than card counting. Is he right?

    Unfortunately, he wasn’t looking hard enough. Even though his profits were rising his win rate was plummeting. After 10 flips he had a 4/10=40% win rate. After 100 flips his win rate was down to 10%. At 1,000 hands it had dropped to 3%, and by 10,000 flips he was all the way down to 1%! If he had been looking at his win rate instead of his profit then he would have seen his advantage slowly diminishing the more he played. That should have been his first clue that the system was slowly failing, not winning. Also, the fact that his win rate was still fluctuating so wildly, even after 10,000 flips, should have indicated that he was nowhere near an accurate result.

    Unfortunately, this is a trap that many players fall into. That is why profit alone cannot be used to determine advantage. It is also why so many people prefer computer simulation over "kitchen table" tests. The results are much more reliable and it can often take less than an hours to see the results of billions of hands. A computer simulation can also give you valuable information like bankroll requirements and profit probabilities for any number of hours of play. With the speed and power of today's software there really is no reason to test a system the old fashioned way.

  2. ChefJJ

    ChefJJ Well-Known Member

    With many of these computer sims, is there a way to take a statistical "slice" of those billion hands? Those slices could represent, say, a year's worth of playing that system...that would give that individual an idea of how the "intermediate run: may behave.

    Just curious.
  3. Sonny

    Sonny Well-Known Member

    The standard deviation will tell you what range your results will fall into for any given length of time. It can also be used to find the probability of being ahead (or behind) by $X after any given amount of time. That should give you a pretty good idea of what your “slice” will taste like. :)

  4. ChefJJ

    ChefJJ Well-Known Member

    All of this "slice" talk is making me hungry for some pizza! Thanks for the info Sonny.
  5. fwb

    fwb Well-Known Member

    "But I'll never play billions of hands..."
  6. Sonny

    Sonny Well-Known Member

    But doesn't it make sense that the system with the biggest advantage and smallest variance will give you the biggest chance of being ahead in the short run? The less you rely on luck the more likely you are to win, the more money you expect to win, and the sooner you will expect to get that money. Unless you have very accurate results you won’t really know which system is better than the other. That is why computers run billions of hands even though humans never do. If you don’t expect accurate results, why waste your time testing a system?

    Obviously professional players don’t play a billion hands every year. They may only need to play a few hundred hours to ensure a profit and less than 1,000 hours to have a good chance of reaching the long run. That’s a measly 20 hours per week. That’s why so many people use blackjack as a form of supplemental income. You don't need to play billions of hands.

  7. Marsha

    Marsha Member

    You are reading my mind! No wonder this forum is called voodoo. Now i need to come up with a whole new set of questions.
  8. Canceler

    Canceler Well-Known Member

    C'mon Marsha, you can do it!

    Most of those new questions have already been answered in the Card Counting forum. That's where you need to start hanging out, instead of here in Voodoo! ;)
  9. Preston

    Preston Well-Known Member

    My win rate is a really good 83%.

    i have 63 wins for the year 5 break evens and 8 losses. Trouble is a couple of the losses were pretty significant and some of the wins were pretty small.

    I'm still up about $6000. (since June 1) took a $1500 loss tonight. My unit is $10 -> I had four hands in a row with $100 bets out that were unsuccessful double downs... which is what most of the hit came from.

    I don't know the exact amount I am up since my old laptop died and that's where I was tracking everything. I was up around $1500 last I remember. So $7500 for the year so far -> Not bad for a "part time" job.
  10. its amazing how often you hear counters and smart people on here say "ya, i tried the system out, it works pretty good" or you will hear somebody say "have you tried that system? does it work"?.. sometimes people will agree such and such is ploppy logic, but then they will be using that same logic later on.. its like they are fast to admit that AP logic is correct, except they dont use it or really think about it

    83% win rate? you mean session win rate? also, i sure as hell hope your counting and spreading nicely, because if not, im jealous! (of results, not approach, if u are indeed a bs player only)
  11. Mr. T

    Mr. T Well-Known Member

    I agree with Sony on this one

    You cannot look at 1 result or a batch of results and draw your conclusions.
    Where I play everybody takes even money on BJ and stand 16 vs 7. When I lose this one the others will say they are right. Even money on BJ the house has a 3.8% advantage and you connot see the diference in play. In the same way hitting 16 vs 7 is not even a close call but everybody on the table would piss me off for doing that. You can see these differences only on zillions of computer sims.
    I know what my house advantage is where I play and I swear by this. So I don't pay any attention to 1 results or even session results which could be very high losses or win and get sad or happy about it. I know that with the house advantage my losses at X rounds per hour, Y$ bet will be Z$. The Comps and the entertanment valve should outweigh this.
    But I try to tell this to others an nobody would pay any attention to me.
  12. Preston

    Preston Well-Known Member

    I've had a couple sessions since but yes I'm talking about winners versus losers. I consider a win to be $25 or more. Anything less counts as a break-even. I use the $25 rule going the other way. My win last night was $600. I had a BEAUTIFUL $1500 shoe (took a while to get to those blackjacks but when they came they CAME!!) $600 for two hours of work. I'll take it.

    I am counting. Spreading. Playing off the top of shoes and wonging out at necessary points. I use mentor count with appropriate indexes.. occasionally I'll break from index play on intuition.. or because I'm holecarding :).
  13. Kasi

    Kasi Well-Known Member

    I know what you're saying but I don't see why not.

    Like with Sonny's original numbers, after only 10000 hands, you would not draw a conclusion that the game must be fixed? Kind of thing.

    Nothing to lose by figuring it out periodically and see what's up. That's all.

    And, while even money with a BJ may have a 3.8% disadvantge, that's not what it costs you in HA even if you took even money everytime you got a BJ.
    Which maybe explains why the effect is barely noticeable.
  14. is that 3.8% with DD? because i know its about 7% for 8D, because even money and insurance are the same thing
  15. Kasi

    Kasi Well-Known Member

    By even money I mean only those cases when a player has a BJ.

    If a player has a 4,2 vs a dealer Ace, he may still take insurance but it is no longer "even money".

    7% is way too high, even for 8 decks, assuming you mean your disadvantage when you are dealt a 2-card hand vs dealer Ace.
  16. its actually 7.x% for 8 decks, and i could prove it but i dont feel like thinking right now, but its quite well known.. im talking about the house advantage for insurance.. i wasnt aware the house advantage changed when you are talking about even money, because even money and insurance are the same thing, so wouldnt they have the same house edge?
  17. Kasi

    Kasi Well-Known Member


    I see where ur coming from.

    Where I'm coming from is that, that average 7.x% HA on insurance you talk about is applied to only a half-bet 1/13 of the time.

    So, the expected loss from always taking insurance, or, in other words, the amount by which the HA would increase, is more like 1/13*.074*.5.

    It's quite well-known, should you ever choose to think about it at another time than now.
  18. the bottom line is, if you did a sim of taking insurance in 8 decks, you would lose 7-8% of your money.. when i say house edge, im not talking about THE house edge, im talking about the house edge on insurance only.. i let people know that taking insurance is 14x worse than the entire game of blackjack itself (of course, not for them, who are playing at like a 4% house edge probably)

Share This Page