## “The next spin must be….” Roulette Systems

I am still amazed at the players piling thousands of dollars worth of casino chips on ‘black’ simply because the ten previous spins have been a red number. “The odds of there being eleven red numbers in a row must be thousands to one” they cry. “Surely the next spin has a greater chance of being black”. They are only partially right.

I am still amazed at the players piling thousands of dollars worth of casino chips on ‘black’ simply because the ten previous spins have been a red number. “The odds of there being eleven red numbers in a row must be thousands to one” they cry. “Surely the next spin has a greater chance of being black”. They are only partially right – the odds of eleven red numbers in eleven spins is very low, but you can’t bet on eleven spins. You can only bet on the next spin, and that spin has exactly the same chance of the number being black as any other spin – close to 50:50.

Players who subscribe to this thinking are committing the classic gambler’s fallacy. The gambler’s fallacy is the mistaken notion that the odds for something with a fixed probability increase or decrease depending upon recent occurrences. Gamblers are led into this fallacy by confusing the odds against a whole sequence with the odds against any event in that sequence. This ‘fallacy’ is not only applied to the expectation of a ‘red’ or ‘black’ number, but any roulette strategy that suggests a particular number, group of numbers or type of number is due. For example, I sat next to a player once who would only bet on the 17 numbers that had not come up in the last 20 spins. This was a convenient way to play because the electronic board above the wheel would show the last 20 numbers. If this strategy actually worked, do you think the casinos would give you this information? They introduced these electronic boards because they knew that players would fall victim to this fallacy, and would wager large amounts when they mistakenly believe that something is ‘due’.

Many roulette systems being sold on the internet are based on the mathematical theory called the Birthday Paradox. This is just another outcome prediction strategy that is disguised with a fancy probability theory. Very briefly, the Birthday Paradox states tells us that when there are 23 people in the same room, there is a 50/50 chance that two of these people will share the same birthday. In an attempt to apply this to Roulette, these systems try to convince us that there is a greater chance of, for example, the last ten numbers spun coming up the next spin. Although the Birthday Paradox is a valid mathematical theory, it can’t be applied to roulette. The reason for this has something to do with the fact that those ten numbers are not spun at the same time. To explain any further than this I may have to take a course in statistical probability, but until then you will just have to trust me.