Slot Machine Myths

April 19, 2017

by Henry Tamburin

A lot of casino players love to play the slots but the majority don't understand how they work. “Theories” have developed amongst slot players to explain they’re playing results and observations. Worst yet are published books and articles that often contain misleading and sometimes incorrect information about slot machines. To set the record straight here are the most talked about slot machine myths and the real truth.

1. If I leave a slot machine and someone else immediately plays it and hits the jackpot, that player has won “my jackpot”.

Sorry, but that is not true. Each slot machine contains a computer chip that is constantly generating a random number that varies from 1 to 16 billion (or some other very large number). The computer generates these random numbers in milliseconds. The minute you place a coin into the slot or when you pull the handle or press the spin button whatever the random number happens to be in that split second corresponds to the symbols you will see on the screen. The computer will compare the random number to a “lookup table” that contains a specific outcome (the symbols you see) corresponding to each random number. The bottom line is that even if you stayed on that machine for one more spin there is no guarantee that you would have hit the spin button at the exact millisecond corresponding to the specific random number that corresponds to the jackpot. Even when a slot machine sits idle the random number is doing its thing. All you do when you play is “select” a random number that corresponds to the outcome you see on the reels. The outcome is then compared to a pay table to determine the payout amount.

2. The outcome of a slot machine is dependent on the number of coins played or the outcome of previous spins.

The outcome of a slot machine is completely random and independent of any external influences. The myth of a slot machine being ‘cold” because it hasn't paid out recently is just that, a myth. The computer that generates those random numbers is cold hearted. It doesn't care whether the last 10, 100, or 10,000 spins were winners or losers and it makes no difference whether you are playing for nickels or dollars. Every selection of the random number (and corresponding outcome) is completely random.

3. Every stop on the reel has an equal probability of showing.

This was the case with the older slot machines. If a reel had 20 symbols, then the chance that a symbol would appear on the paying is 1 in 20. In other words any symbol had an equal chance of showing on the payline. In the new computer controlled slot machines this is not the case. There may be 20 physical stops on a reel but each stop does not have the same probability of showing on the payline. The computer uses a mapping technique to convert the large number generated by the random number generator into a smaller number or integer that is mapped to the stops. Thus a specific stop on the reel (say the number 7) may have just one integer mapped to it whereas their may be a lot more integers mapped to a blank space or a cherry. By changing this mapping scheme it’s possible for a casino to change its advantage on the machine (and that’s without changing the reels or the payout schedule).

4. Casinos can set slot machines to pay back more during the weekend and less on the weekend.

Casinos do not fiddle around with slot machines to change the pay out percentages. In Atlantic City, casino aren't allowed to change a computer chip in a slot machine unless they first notify the gaming regulators and then a specialist from the Division of Gaming Enforcement must be present when the chip is changed. Nevada regulations allow casinos to change chips on their own but they must use a computer chip that has been approved and they must fill out a lot of paper work (they also get audited from the regulators who check that only approved chips are in the slot machines). Casino managers usually change a payback on a slot machine when they order a new machine. In fact slot manufacturers provide a spec book that contains all the available hold percentages for different models and denomination of machines. The slot managers simply orders the make, model and hold percentage and the machine is delivered with the right computer chip that is certified to give that hold percentage with a certain volatility (this is known as the slot machine volatility).

5. Slot machines pay back more when you use a slot card.

This is another misconception. Those little ole computer chips don’t care if you are using a slot card or not. Remember all they do is generate random numbers. Therefore whether or not you insert the slot card in the reader does affect the machines payback percentages. However, using a slot card will increase your overall return because part of the money you insert into the machine will be returned in the form of cash rebates, fee meals, discounted rooms, and other comps that is a benefit for joining a casino’s slot club program.

6. Slot machines located near casino entrances or at the end of aisles are programmed to pay more.

After interviewing several slot managers from different parts of the country, only one gave me a hint that he put the looser slot machines at the entrance to his riverboat and at the end of aisles where the machines tend to be visible to play more players. The fact is that most slot managers nowadays group their slot machines by the same denomination on the casino floor and the difference between the payback from one slot to another of the same denomination is very slight (often 1% or less).