So let’s take a closer look at this strategy. First of all it’s called Martingale and has been played properly as long as roulette itself. It has just a few very simple rules:
• Start with one betting unit (e.g. 10$)
• If you win => pocket the win and start over again
• If you lose => double your bet (going from 1, 2, 4, 8, 16, 32….)
That’s it ! This will win you one betting unit most of the time. And give you a false sense of security. Until you hit that one big losing streak which will erase all wins.
The above table shows all possible combinations after five rounds (without the fatal green zero(s)). Without the green zeros the chance to hit red or black is fifty percent each. Now analyze the possible outcomes if you bet on red every time following the rules above:
As you can see in the above tables you will bust once out of 32 times. When you do you will lose a total of 31 units. The other 31 times you will win one unit each. This results in an expected value (EV) of:
(31/32 * 1) + (1/32 * -31) = 0
So you are not making a profit…but you are also not losing like I said before. This is because, as already mentioned above, we neglected the zero(s) which is making the roulette unprofitable. But showing no profit if the rules are not as bad as in the casino should already demonstrate that the method is not working as advertised.
If we include the green zeros into the above tables the chance to win is getting smaller (lower than fifty percent). Hitting the correct color has a chance of 18/37 = ~48.6% (single zero) or 18/38 = ~47.4 (double zero). This results in a negative EV for this betting system which is called Martingale.