How Can a Machine That Pays off at a Certain Percentage Be Random?

Riddle me this, QoD. A slot machine has a sign that says it pays off at 98%. Right? On the other hand, the chances of hitting any jackpot on that slot are random. Right? How can a machine that pays off at a certain percentage be random?

And, Does a slot machine know when to start paying, because it's paying less than the minimum of 75%?

The answer to the first question also, perhaps indirectly, answers the second. The direct answer to the second is that the slot machine doesn't "know" anything and it can pay off at zero percent in the short run (think 20 spins without any payoffs). But in the long run, it will return more than 75%, the minimum allowed, at least in Nevada.

Now, though slots can't know anything, certain things can be known about them. That's because "random" doesn't also mean completely "unpredictable."

Consider, for example, drawing from a deck of cards. We know we can draw a king of hearts. We also know we can never draw a jack of livers or a queen of spleens. We know that those cards aren't in the deck.

What’s random about drawing from a deck of cards is which available card you’ll draw next. Now, despite this randomness, we know all sorts of things about the cards you might draw. For instance, one-quarter of the time, you'll draw a club, one-quarter of the time a diamond, one-quarter a spade, one-quarter a heart, and never a liver or spleen. We also know that 1-13th of the time, you'll draw an ace, one-thirteenth of the time a deuce, and so on. How can we know these things? Because we know all the cards that populate the deck from which you’re drawing.

A slot machine works in exactly the same way. There's a "population" of possible outcomes and the random number generator is used to select one of those outcomes as the result of a spin.

We don't know what result will appear next, but we (meaning the manufacturer and the casino) know how many times each combination appears in the total population and, therefore, how likely it is for any combination to land on the payline. With that information and the paytable, we can calculate the long-term payback for the machine.

Note the use of "long-term" to qualify "payback." Over the short-term, anything can happen. But as the machine gets more and more play, its actual payback will get closer and closer to its long-term expected value.

Number of spins, incidentally, is how time is measured on a slot machine. Given the number of spins, we can calculate the range in which the actual payback on a machine should fall with a given degree of certainty. The actual payback on most machines is within a percentage point of the machine's long-term payback after a million or so spins.

So the answer to your question is, a casino can honestly and accurately claim that a slot will pay back 98%, but no one knows where the returns will show up to make up that percentage.

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Lucky Dec-06-2023

Players card

Few months ago, while playing a slot at Harrahs Laughlin, a "very knowleable" player sitting next to me explained that I should not put in my Diamond Card, as once you get to Diamond, the machine pays less if you put your card in.  The higher your status, the lower the payouts.  He said he knew someone that knew a slot attendent in Vegas.  Said it was rock solid information.  Put my card in, and 3 spins later won the progressive.  Guy got up and walked away.

jay Dec-06-2023

Bunk

Lucky: that rock solid info is complete bunk. 
I have a couple of slots and a linked progressive in my basement. 
Each time a coin or credit is played a contact between two pins is closed momentarily. This tells the progressive controller to increment the jackpot by whatever increment is programmed into it. When a jackpot is hit those two pins close and stay closed which tells the controller that the jackpot has been won. On the slot side it locks up until you turn the jackpot reset key on the side of the machine to clear the hand pay condition.

There is absolutely no information shared between the progressive and the slot. 


Players cards work in a similar way you have a terminal in the slot that gets told a coin or credit has been played and the terminal reports back to the central computer to say how many points you should get. The terminal can read your card and display some info on the display like hello Frank or welcome gold member.

Robert Dec-06-2023

Misconceptions

There's perhaps no greater wellspring of superstition in a casino that what people believe about slot machines. Playing with or without a player's card, believing that a machine is "due" to hit (with the exception of some progressives), placement of the machine on the floor, etc.

In the end, they are MACHINES, programmed to return a specific percentage, as this QOD explains. They all have to be approved by the Nevada Gaming Commission before they even hit the floor, and certain rules and protocols must be met. Tribal casinos do things differently.

A friend of mine is convinced that if he "stops" the reels before the spin is complete then that gives him an advantage over it. Nope, once you hit the button the result is determined and all that stopping does is show you that result sooner. He's not a dumb guy, but refuses to believe that's true. He also thinks that playing at certain times of the day are luckier for him. Such is the power of superstition.

Kenneth Mytinger Dec-06-2023

Early video poker miscues

(I think Deke already knows this)

Some very early video poker machines dealt five stacks of two cards each.  But that made lots of hands impossible to achieve.  It got fixed pretty quickly ...

King of the Bovines Dec-06-2023

It's bad luck to be superstitious...

I was a computer programmer once upon a time, and the '10 cards' makes perfect sense from a programmer viewpoint.

You get the random number, grab 10 random cards, and you're done with the random number and the deck.

At first blush, the return is the same either way, but the 'draw 10 to start' method means that the player could literally be drawing dead on getting a winning hand.

No one likes to find out that they don't have a chance to win...

Lucky Dec-11-2023

Players Card Bunk, Jay

Jay, my point was, although I did not express it correctly, was that that "knoweledgable" player was full of s*it.  Putting in or not putting in the players card means nothing other than, in this case, Caesars, could track my play.  And as for the progressive, my point was, again not expressed correctly, that the players card had no bearing on the win, or the loss. And my walking away was letting the idiot next to me know that he had absolutely no idea what he was talking about. I am very well aware as to how slots and the tracking programs work, and the electronic barriers that separate them.  I did not know that the advancement of the progressive was done via an actual physical contact closure.  I thouhgt that with all the new technology it was done and accounted for electronically.  The mathamatical solutions to get to the progressive, if usually playing full coin in, usually has some game permutation that makes it much harder to hit the progresive.

Question of the Day - 06 December 2023

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