Return rate or redistribution rate

Different games often advertise a return rate that seems very high: 98% for example, or 75%, or 50%. Many people think this means you have a 50, 70 or 98% chance of winning. Not at all! A return rate of 86% means that, out of all the bets made by players, the company organizing the game deducts 14% for its own profit and therefore only redistributes 86% of the sum, divided between all the winners. In other words, in the long term, you're guaranteed to lose 14% of all your bets. Let's take the example of a game that advertises a 95% return rate. The stake is 1 euro and the duration is such that you can play 5 times a minute, i.e. 300 times an hour. The 95% return rate means that every time a player spends 1 euro, the organizing company takes 5% of this sum, or 5 cents. At the end of an hour, on average, given that there are 300 games per hour, players lose 5 centimes x 300 = 15 euros. It's mathematical. Of course, there are times when you win, sometimes even big sums. But if you play a lot, over the long term, and add up all your wins and losses, you're guaranteed to lose an average of 15 euros per hour played.

This is known as negative earnings expectancy: lose money.

Gaming suppliers have more than one trick up their sleeves to attract players. For example, studies carried out in Quebec (Sévigny et al. 2005) on a large number of online gambling sites show that return rates in excess of 100% are not uncommon in the demo phase of games to convince players to continue.