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# Ask the Slot Expert: Can identical slots have different bonus probabilities?

9 May 2012

I have two slot machine questions that I've wondered about for some time. It seems like you'd be the perfect person to ask.

1. When slot manufacturers construct the slot games, do they or the casino purchasers determine what the min/max payback percentage figures will be?

In the tribal compacts that I've read the minimum payback for "non-skill" slots is in most cases 80 percent. Can/do the tribes specifically order machines that have an 80 percent payback or do they just have to accept whatever the manufacturer has designed and constructed, be it 85 percent, 92.5 percent, 97.8 percent, etc.?

2. Can supposedly identical side-by-side slot machines have different bonus arrangements?Does the casino have the ability to alter the bonus feature so that it appears in one slot machine but not in the adjacent machine?

My wife and I many times have played the same game, side by side, and many times one of the machines will continually have a bonus feature appear that we never see appearing on the other machine.

I've searched your archives but didn't see anything specific to these two questions.

Thanks,
Dick

Dear Dick,

Thanks for your confidence. I won't let you down. You mentioned compacts, so I'll describe Class III machines, the kind you find in Las Vegas, Atlantic City, Tunica and at Native American casinos with state compacts.

Legislation or compacts usually determine the minimum and maximum long-term paybacks on slots. Well, really just the minimum. The maximum is 100 percent. The slot manufacturers devise reel layouts whose long-term paybacks fall in the allowed range. Most slot machines have multiple long-term paybacks available. The casino then specifies which of the available long-term paybacks available it wants on its machines when it orders them.

The answer to the first part of your second question is yes. Two seemingly identical machines can have different bonus probabilities or different long-term paybacks or both.

The answer to the second part of your second question is no. The only way the casino can alter the machine is by changing the reel layouts (or pay table). Furthermore, regulations usually require that any winning combination or event in the pay table must be possible on the machine. It doesn't have to be likely, but it has to be possible.

The situation you described (one machine frequently hitting a bonus feature and another not) sounds like normal randomness to me.

Jackpots for all,
John

Send your slot and video poker questions to John Robison, Slot Expert, at slotexpert@comcast.net. Because of the volume of mail I receive, I regret that I can't reply to every question.

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