Ask the Slot Expert: Is the RNG dead?

Question: I’m extremely new to gambling. I love to play the slots. I watch all the YouTubers and over the last few years I’ve even hit a few handpays.

I have a question that I’m sure you’ve answered hundreds of times. Most people that I’ve heard talk about it say that all slot machines on the casino floor have an RNG. The outcome of the game is based solely on the millisecond you press that button. Timing is everything.

This is what I’ve heard and believe to be true. Lately though I’m hearing that RNGs are a thing of the past and all new slot machines on the floor are using a central control room and are server based.

They aren’t saying that, in the middle of you playing, the casino can change your payback percentage but that they can after a machine is idle for a period of time.

I’m just confused and looking for some expert information on the topic.

Are RNGs dead?

Also I read some things you have written about the players card. If I win a jackpot for $2100, is the casino going to use my players card against me and try to get all that money back?

Sorry for asking the same question that I’m sure you’ve answered a million times.

Answer: I don't mind re-answering questions. Even though two questions are about the same basic concept, readers ask them in different ways and I try to give different explanations and different examples in each answer. I hope that I eventually give an answer that clicks with each reader.

As I said last week, it used to be so easy answering questions in the How do slots determine their outcomes? category, but now there are many different methods. The method used depends on where you are and it isn't always easy to determine which method is used by a particular machine.

You bring up a few concepts in your question about the RNG and not all of them are mutually exclusive.

First, the RNG is definitely not dead. There is nothing on the horizon indicating that Las Vegas, Atlantic City, Mississippi, etc. -- let's call them corporate casinos -- are going to switch their machines to a different technology.

It's true that timing is everything. It's also true that timing is nothing. Your outcome is determined by the numbers generated by the RNG when you hit the button, but being a little faster or slower won't make your outcome necessarily better or worse -- just different.

These machines may determine their results independently, but they can use a central server for some functions. One of these functions is downloadable games, in which a casino can change the long-term payback or game on a machine without having to visit the machine and change hardware in it. The new game is sent to the machine over the casino's internal network.

As you said, regulations prevent the casino from changing a machine while it is being played. In Nevada, a machine has to be idle for four minutes before it can be changed. Then it must display a message that its configuration has been changed for another four minutes. Depending on jurisdiction, the casino must also file paperwork with the local gaming control board informing it of the change.

Things get muddier when we move from a corporate casino to an Indian casino. Depending on whether the tribe has a compact with the state, the casino will have RNG-based games (called Class III in this context), bingo-drawing based games (Class II) or both. Tribes need state compacts to offer Class III machines.

In Class II machines, a central computer conducts a bingo drawing and communicates the numbers drawn with the machines on the slot floor. The outcome of a play is determined by the pattern filled on the internal bingo card in each machine. Each Class II machine must display the bingo card used in determining its results and it must give the player the opportunity to change the card.

We have two methods for determining the outcome: RNG and bingo drawing. Let's add a third one. This method is sometimes known as Central Determination or Finite Outcome. (Unfortunately, the slot industry never settled on precise meanings for various terms.)

Instead of having a bingo drawing under the hood, what if we had the electronic equivalent of lottery scratchers. Each time we hit the Spin button, our machine buys a scratcher from a central server (the lottery agent). The prize on that ticket determines what we win. If the ticket says that the player wins $5, one machine may display that as mixed bars while another displays two cherries. When the central server uses up all of the tickets in a pool, it creates another pool.

You usually find this method only in machines in casinos run by state lotteries. The machines are usually called Video Lottery Terminals, although the term has also been used to describe RNG-based machines. As I said before, the industry never developed precise terminology.

In summary, we have three ways to determine the outcome on a slot machine, each with varying degrees of independence. The RNG-based machine is completely independent.

Next is the bingo-drawing-based machine. It depends on a central server for the bingo drawing, but what the numbers drawn are worth depends on the card the machine is playing. The same drawing gives different results on different machines.

And finally we have Finite Outcome. These machines are completely dependent on another machine. The central server tells them how much a play wins. The same result from the central server yields the same win on all the machines participating in a pool.

The people who say machines are server-based (another term not precisely defined by the slot industry) may be correct. And the people who say machines are RNG based may also be correct. It all depends on the technology used by a particular machine.

One of the regulations governing the RNG in Nevada is that it must be free from any outside influence. That means that the time of day, the day of the week, the number of people in the casino, the past performance of the machine, the presence of a players card, and how much the player has won or lost have no effect on the results on a machine.

There's no way for a casino to alter the operation of the machines you play to try to win back money you've won. It just seems like they can.

Slot machines are all negative expectation games. If you play long enough, they'll win all of your money.

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