There are some claims on another site that I believe are highly misleading and could lead players astray. (No one here) I thought a response was needed. The claim is that the real house advantage is 17% and that casinos (and all authors which he claims work for casinos) lie when they say it’s 0.5%. As “evidence” of this claim, is the fact that a person with $100 that bets at a $10 table will quickly lose his money, even though at an edge of 0.5% the EV is a mere 50 cents a hand. Well yes, the EV per hand is small. But, the player doesn’t win or lose 50 cents per hand. The player mostly wins or loses $10 a hand, and more with doubles, splits, resplits, and doubles after splits, and yet more if he doesn’t flat bet. Most superstitious players don’t flat bet.

I ran a sim with about 10,000,000 sessions. Each session started with $100 and played until the $100 was lost or 500 rounds were played. The player played perfect basic strategy and flat bet $10 per hand. Six decks, S17, DAS. Results:

House edge .43%
Losing sessions 73.4%
Bankrupt sessions: 71.1%
Average rounds before bankruptcy: 134

What we see is that the player usually loses all his bankroll after an hour or so, even though the edge is only a half percent.

Next sim. The player plays a very mild negative progression. $10, then $20 on a loss, then $40 on another loss, then reset to $10.

House edge .42%
Losing sessions 83.9%
Bankrupt sessions: 83.6%
Average rounds before bankruptcy: 79

We see the same house edge (within the sim’s standard error of .006%) -- but the player now bankrupts more often and in 79 rounds on average.

Next sim, a mild positive progression:

House edge .43%
Losing sessions 85.6%
Bankrupt sessions: 85.2%
Average rounds before bankruptcy: 76

Pretty much the same. Raising the negative progression to 8 units and resetting only after a win brings bankruptcy up to 94.5% of sessions after an average 30 rounds.

These results are using perfect basic strategy, which most players do not use. The last sim run with a never bust strategy results in bankruptcy 98% of the time.

What we are seeing is that a player betting at least 10% of his bankroll isn’t going to last long even with a house edge of half a percent due to the inherent variance in blackjack.