The History of D'Alembert
Of all the roulette betting strategies in existence, D’Alembert is one of the oldest and most well-known. The basis of the strategy was developed back in the 18th century by the French mathematician and philosopher Jean le Rond d’Alembert, one of the most celebrated thinkers of his era. His statistical theory that forms the foundation of the D’Alembert betting strategy went as follows: in an equation where there is a 50:50 distribution of odds (i.e. a coin toss or red vs black), then the results will, eventually, even each other out and produce an equal distribution of results.
Let’s illustrate this with the coin toss example. According to D’Alembert, since there is always a 50% chance of landing heads or tails, statistically you will eventually get an even number of each. Therefore, every time you land on heads in a row, the odds of getting tails on the next turn will increase.
Both results will occur an even number of times in the aggregate, meaning that should you flip the coin 1000 times, you would end up with something close to 500 heads and 500 tails. It is easy to see why this appeals to roulette players, since the standard wager bets on either red or black, both of which appear on the roulette wheel in equal measure.
However, when you actually look at the roulette odds, it is clear that D’Alembert’s strategy does not hold up. After all, the inclusion of the zero pockets on the roulette wheel (“0” or “00”) means that the odds are less than 50:0. Rather, the odds are 47.37% on a European roulette wheel, with a 2.7% house edge.
Furthermore, if you land black on the roulette wheel, the odds of landing on red on your next turn does not increase at all, it remains the same. Nonetheless, D’Alembert remains an option for structuring your bets the next time you are playing Roulette.