Math clarification on running it twice

jfarrow13jfarrow13 Red Chipper Posts: 1,254 ✭✭✭✭
Was watching LATB tonight, they ran it twice when before he had ran it once with a OESD + BD flush. The commentator said "wow, that's generous. Yeah, I mean generally you don't wanna run it more than once, you lose edge. But, in a fun communal game like this, it's fine". Am missing something about math? Sure, you give a guy a chance to win back half, but the guy with AA was like 65% to 35%, but how do you lose edge by running it more than once? Is it because if you "hold" the first time, his % will increase ever so slightly on the 2nd time, therefore, you lose "edge?" But by the same token, if he "sucks out", when then he burned some of his "outs" to catch up to you, meaning he's that less likely to win the 2nd time, so sure you might "split", but really, run over 10,000 times, the true math of the 65% win vs 35% lose will come into play, instead of the somewhat randomness of the 35% chance of just running it once. He also mentioned something about running it twice really allows players to play flush and straight draws hard and fast, so it "hurts NIT's games" running it 2+ times....but if that's the case....what? Can't the NIT just do the exact same thing, and maybe he splits the pot, but I mean he doesn't "lose" edge any more than if he ran it once and got "sucked out on" and had to go home? Thought running it twice decreased "variance" by adding larger sample sizes.

Math friends @jeffnc or @Red ?


  • RedRed Red Chipper Posts: 2,308 ✭✭✭✭
    Running it twice/etc is used to reduced variance. Used mostly by (high stakes?) poker players who want to avoid big swings aka reduce variance.

    Also I don't see what edge we could here. By definition, "having an edge (on someone)" is having an advantage (on someone). Like having a card edge (stronger / more nutted range), a position edge (being in position), a skill edge (better understanding of the game), etc.
    I don't think it applies for running it 2+. Not that I ever heard of.
    jfarrow13 wrote: »
    Is it because if you "hold" the first time, his % will increase ever so slightly on the 2nd time, therefore, you lose "edge?"
    Technically you could adjust players' equity based on the cards out on the first run(s). But why? It serves nothing but the show (on TV/internet, for the viewers) as players can't use this information during the play... both ot them are already all-in.
  • Yanming ZYanming Z Red Chipper Posts: 294 ✭✭✭
    The logic behind this is if you are the person who tend to "run it twice", people will play draws more aggressively against you because they can avoid big swings with 2 chances of getting there. If you never agree to "run it twice" people are less likely to shove with a draw. So in a sense, "run it twice" will make hand reading more difficult.
  • jeffncjeffnc Red Chipper Posts: 4,998 ✭✭✭✭✭
    If by "edge" he meant math edge, then it's nonsense. It's easy to think about it this way with an extreme example. You reduce variance if you run out the entire deck (run it 40 times or whatever). That way you're going to approach your actual equity in the hand. For example if you have 65%, then you're actually going to win 65% of the pot. (The only details have to do with burn cards, player cards unshuffled back into the deck, etc.)

    The only "edge" you can gain is not a mathematical one but a psychological one. Some people are more afraid to play hands in big pots if they know you'll only run it once, so it can reduce gambling. Sometimes you'll hear someone ask "if I call, run it twice?". So those people are more likely to be pushed around, I suppose.
  • jfarrow13jfarrow13 Red Chipper Posts: 1,254 ✭✭✭✭
    Gotcha, last time I ever trust $25/50 players commentary.
  • persuadeopersuadeo Red Chipper Posts: 4,296 ✭✭✭✭✭
    The average mid stakes poker player is highly likely to be either high, chasing digital investments he can't explain, in debt, backed, playing with family money, or riding a wave of variance. Trust no one.
  • jeffncjeffnc Red Chipper Posts: 4,998 ✭✭✭✭✭
    persuadeo wrote: »
    chasing digital investments he can't explain

    good one!

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