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Ask the Slot Expert: How does the amount of money played on a machine affect the RNG?

27 December 2017

Question: I understand how slots use the RNG. How does this interact with how much money players over time are putting into one particular machine? Does a machine that is played a lot by many people have a higher chance of paying out over time than one nobody seems to play?

I'm trying to figure out if more popular machines have a better chance than ones that rarely get played and to understand how the RNG interfaces with total dollars put into a machine over a period of a week, month, etc.

It seems that a lot more money going into a specific machine would affect its payout frequency versus one that is rarely played.

You have two pairs of dice, one red and one blue. You throw the red dice 100 times and you don't touch the blue dice at all. What is the probability of rolling a 7 on both pairs?

The same, right? Not rolling the blue dice for a period of time has no effect on how frequently numbers will be thrown.

Now consider two identical slot machines sitting side by side. The machines are identical in every respect except for serial number. They have identical hardware and software. You watch them for a while. The one of the left gets almost constant play, but for some reason no one plays the machine on the right.

Which one is more likely to pay? Neither is more likely. The odds are the same on each machine.

The only input to the RNG function is the prior number generated. The RNG has no external influences. The number stream is not affected by the amount of money played on a machine (or the time of day or the day of the week or whether it is a holiday or whether the casino is empty or crowded or how much the machine has paid out in the past or whether you're using a player's card...).

The answer to your question about how the RNG interfaces with the total dollars put into a machine is: It doesn't.

A machine that rarely gets played takes a longer period of time to home in on its long-term payback percentage. Rarely played machines can also report some strange numbers for monthly win/loss. Many casinos have few machines in the very high denominations, like \$25 and above, and the machines sometimes get very little play in a month. You may see very low paybacks published for these machines in the casino magazines. The few players who played the machines that month were unlucky. Or you might see very large payback percentages. That means the players were lucky.

The cause of the widely varying monthly payback percentages is the small sample size. The more play a machine gets, the closer its actual payback percentage will be to its long-term payback percentage. If you looked at the total amount of money played through the machines and the total amount of money they've returned to players, the payback percentages would be much closer to the long-term payback percentages of the machines.

Contrast the situation with the few high-denomination machines with that of the many low-denomination machines. The payback percentages for penny, quarter and dollar machines in any given casino will be about the same from month to month. The machines get so much play every month that their actual payback percentages are always close to their long-term percentages.

Popular machines do not have a better chance than less popular machines. But there is something more popular machines are more likely to have.

The more popular machines are more likely to have someone playing them when you want to play them.

Question: I was at the Treasure Island casino in Minnesota. There was \$1,135 left in a slot machine. My friend went up to it, pushed spin, cashed it out, put it in another machine, hit spin twice, cashed it out, and then went and got the money and left. Then a tribal police officer said that she'll be charged for taking that money. Can she really get charged for this?

Answer: Hmm. It sure seems like your friend was trying to set up a complicated chain of custody to obfuscate the source of the funds. Here a spin, there a spin — Where did that money come from?

The precedent of Finders Keepers v. Losers Weepers does not apply to found money in a casino. Regulations and laws differ from jurisdiction to jurisdiction, but they all acknowledge that the money belongs to the player who left it, not the player who found it.

You know what most states call taking property worth \$1,135? Grand theft.

I have — er, um — utilized money and tickets I've found left on a machine, but never more than a couple of bucks. I would never take over \$100 let alone over \$1,000.

The best thing to do with found tickets or money left on a machine is to treat them like nuclear waste. They're radioactive and you should stay away from them. Tell a slot floorperson about money left on a machine and leave the tickets where they are.

Cash money can't be traced, but with today's ticket systems, the money your friend took could be traced from machine to machine to redemption kiosk. And with all of the surveillance in the casino, there's nowhere to hide.

As long as this is your friend's first offense, I think the proper remedy is for her to return the money to the casino. There's no reason to press charges against her.

John Robison

John Robison is an expert on slot machines and how to play them. John is a slot and video poker columnist and has written for many of gaming’s leading publications. He holds a master's degree in computer science from the prestigious Stevens Institute of Technology.

You may hear John give his slot and video poker tips live on The Good Times Show, hosted by Rudi Schiffer and Mike Schiffer, which is broadcast from Memphis on KXIQ 1180AM Friday afternoon from from 2PM to 5PM Central Time. John is on the show from 4:30 to 5. You can listen to archives of the show on the web anytime.

Books by John Robison:

The Slot Expert's Guide to Playing Slots
John Robison
John Robison is an expert on slot machines and how to play them. John is a slot and video poker columnist and has written for many of gaming’s leading publications. He holds a master's degree in computer science from the prestigious Stevens Institute of Technology.

You may hear John give his slot and video poker tips live on The Good Times Show, hosted by Rudi Schiffer and Mike Schiffer, which is broadcast from Memphis on KXIQ 1180AM Friday afternoon from from 2PM to 5PM Central Time. John is on the show from 4:30 to 5. You can listen to archives of the show on the web anytime.

Books by John Robison:

The Slot Expert's Guide to Playing Slots