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Ian Bruce

The Gambler’s Fallacy is a form of cognitive bias. It leads a bettor to believe that an outcome has a greater chance of happening than it really does. In this guide, we explain how this common fallacy works, why it is dangerous, and how you can avoid falling for it.

Gambler’s Fallacy Explained

This particular bias, which is also referred to as the Monte Carlo fallacy, is widespread. In fact, if you don’t have it yourself, you’re certain to know someone who does. To find out if you have it, consider the following scenario:

A coin is tossed seven times. On each toss, the coin shows Heads. Now, if you were asked to bet on the next toss of the coin, would you bet on Heads or Tails showing? Most people would choose to side with Tails. That’s because they have fallen for the Gambler’s Fallacy. They believe that, with Heads already having shown up seven times in a row, Tails is now much more likely to show up on the eighth toss of the coin.


Of course, that isn’t the case at all. The odds of Heads or Tails showing on any honest coin toss are always the same. But our human brains can’t help believing that the preceding results in some way have an influence on the results to come.

Gambler’s Fallacy Example

Let’s give you a real-world example of the Gambler’s Fallacy in action. We’ve said that it is also known as the Monte Carlo fallacy, and that’s because of something that happened at the Casino de Monte Carlo in 1913. On that occasion, a series of black numbers started winning at the roulette wheel. There were five black numbers in a row, then six, then seven.

The gamblers at the wheel soon started betting on red, with increasing certainty that a winning red number was just a spin or two away. But it wasn’t. The sequence of black numbers extended to 10, 15, 20 and more. The streak of black numbers eventually extended to 26 in a row, and the people who were betting on red lost millions.

Hot Hand Fallacy

When a run of results happens to be going in your favour, you could just as easily fall for the Hot Hand Fallacy. This is where the previous results lead you to believe that you’re on a ‘lucky streak’ and that you have more chance of winning than you really do.

Consider someone who rolls a die and bets on the number shown being odd. He rolls an odd number three times in a row and begins to feel that Lady Luck is on his side. He might then respond to his betting bias by deciding to increase the size of his subsequent bets to try and make the most of his ‘purple patch’.


If this streak were to continue, his false belief that his chances of winning are particularly favourable would only get stronger, and he might continue raising his stakes as a result. But, once again, his belief has no basis in reality. The odds of him winning or losing on the next roll of the dice are always the same, no matter how successful his previous rolls were.

Note: For those of you who are interested in studying this topic in more depth from an academic perspective, we recommend this paper from The Review of Economic Studies and this one from the Journal of Risk and Uncertainty.

Why the Gambler’s Fallacy is Dangerous

Now that you are familiar with the Gambler’s Fallacy meaning, it should be quite clear that it is something potentially dangerous. That’s because it leads people to bet with the false assumption that an event is more likely to happen than it really is.

Gambler’s Fallacy in Horse Racing

Those of you who have spent any time at all in betting shops will have seen this take place in person. Think of those who like to bet on horse racing and watch the market favourite lose in each of the first five races of the day. In most betting shops, you’d then see plenty of punters better higher amounts on the market favourite in the sixth race. If you were to ask why, they would tell you that it’s because a favourite is now ‘due’ to win. As if they’d never considered the possibility that they might go through the entire racecard without a winning favourite.

Gambler’s Fallacy in Football

A similar situation can be seen among football bettors, both in betting shops and at football betting sites. If a certain team wins four matches in a row, some will automatically start betting on the opposition, assuming that the winning run must soon end. Fans of the winning team, by contrast, might fall for the Hot Hand Fallacy and bet more than they normally do, assuming that the winning streak is sure to continue.

Both of these positions are wrong because they are based on false assumptions. Watching five favourites in a row lose their races doesn’t give the sixth favourite a better chance of winning. And seeing a football team win four matches in a row won’t improve their chances of winning the fifth. Sure, they might have a bit more confidence, but they still need to be better than the opposing team on the day of the match, and that’s never guaranteed.

In short, the Gambler’s Fallacy is dangerous because it leads people to bet on false assumptions and often to bet with larger amounts than the outcome warrants.

How to Avoid the Gambler’s Fallacy

Just being aware of the Gambler’s Fallacy and how it works will help you to avoid falling for it hook, line and sinker. But there are some other things that you can do to make yourself less susceptible to this kind of cognitive bias. Here are four suggestions to consider:

  1. Understand Odds and Probabilities

    The first thing we recommend is that you get a good understanding of odds and probabilities. You might already have this, but if not, take a look at our Betting Odds Explained guide. It will tell you how odds work and how you can figure out the implied probability of an outcome taking place according to the price being offered by online betting sites. This will give you an objective view of the outcome that professional bookmakers have reached.
  2. Remember That Events Are Independent

    While form is always good to take into consideration, you should always view a sporting event on its own merits. Whatever the past results might be, it’s the best-performing competitor or team on the day that is most likely to win. Remember this, and you’ll avoid betting just because a team or player has notched up a sequence of recent wins or losses.
  3. Learn to Be Objective

    In all types of betting, it’s important to be as objective as possible. If you allow yourself to be overly optimistic about a team or player, a previous run of wins is likely to lure you into the Hot Hands Fallacy. If you’re overly pessimistic, you might be tempted to oppose a team or player with a winning run just because you expect it to end soon. Both positions are dangerous, so try to take a step back and make your betting decision based on the match or game coming up, not on how you might feel about the competitors involved.
  4. Look Through Past Results

    Our final suggestion for avoiding the Gambler’s Fallacy is to take some time to look through past results. For example, if you enjoy betting on horse racing, look back at how often favourites win and note those days – and they do happen – when there are no winning favourites at a particular meeting. If you’re into football, tennis or any other sport, look at how even the hottest of favourites have lost to the most unfancied underdogs. This will help you to see, from actual sporting results, that streaks, whether positive or negative, never guarantee anything.


The Gambler’s Fallacy is something that all of us seem to be hard-wired to fall for. According to the BBC, even monkeys fall for it. Fortunately, human beings can use reason and rationality to recognise this cognitive bias and avoid it, and we advise all bettors to do just that.


What is the Gambler’s Fallacy?

What is an example of the Gambler’s Fallacy?

Is Gambler’s Fallacy true?

Is Gambler’s Fallacy a cognitive bias?

Ian Bruce

Ian Bruce joined Safest Betting Sites in 2024 as Senior Sports Editor to oversee the quality and usefulness of its gambling content. He originally developed an interest in betting after landing a winning Yankee on his first attempt. He then spent years figuring out how to replicate that success. Along the way, he became one of the UK’s leading writers on the topic of betting and gaming. Ian’s career has now spanned more than three decades, and his enthusiasm for systematic and responsible betting hasn’t waned one bit. However, his preferred approach to winning these days is Dutching, for the simple reason that “It’s a lot easier than landing Yankees.”