Independence of Events

Independence of Events

ImageAnother gambling concept closely related to randomness is the independence of events. In gambling, independence of events means that what happened before has no effect on what will happen next. Examples include:

  • Every time a roulette wheel is spun, the result is totally independent of all previous spins, no matter what numbers or colours have come up previously.
  • Every time the spin button is pushed on a slot machine or VLT, the result is totally independent of all previous pushes.

An Example: The Coin Flip

ImageWe can use the example of a coin flip to better understand this concept. If you flip a coin 10 times and each time it lands on heads, the chance of getting a head on the eleventh flip remains 50-50. The coin has no memory of previous flips, and previous flips have no effect on current or future flips.

There is a common myth in gambling called the gambler’s fallacy, which is the belief that an event is “due” to happen if it hasn’t happened in a while. Many people don’t realize that, in most cases, the results in gambling are independent of each other. They expect outcomes to even out in the short term. For example, if red comes up 10 times in a row in roulette, some gamblers expect the next spin to come up black. Of course, as in the coin flip, black is never “due.” Previous spins have no effect on the current or future spins.

Exceptions to the Concept of Independence of Events

There are some types of games (see section Does Skill Work?) where previous results can have some effect on what happens next. Blackjack is a good example: once a card has been dealt, it won’t be back in play until all the cards are shuffled again. Previous hands can have some limited effect on current or future hands. Learn more in our Blackjack section.

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