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On Slot Volatility and Hit Frequency

5 January 2009

By John Robison


After reading these articles ("More Truth About Slots"), it reminds me of getting an answer from Casino Player magazine last September about whether to stay or stray from the machine. The answer was because of volatility I should stay.

That's what I think is "wrong" with slots. High volatility and LOW hit frequency. Both make the player's bankroll very volatile. RNG and all that is great but... Volatility is programmed into the slot and that's why casinos want to know the volatility index of the machine from the manufacturer so they can see how much they can get from that machine. The rest is up to us to read your articles and those in Strictly Slots continuously telling us to stretch our bankrolls by playing less coins and making a plan before we play.

Also recently we went to Borgata again in June and soon in September. I noticed that new slots such as Hot Shot Progressive, which is 20 lines as advertised, Borgata made them 9 line. Why? Sure it's great for bankroll but I don't get it. Of all the new games I played only 2 were 20 line (Monopoly) or 10 plus 4th reel and 4+5 for the Extreme reels slot. All the rest were 9 line. Have to notice this more closely next time. Nevertheless, I have to play the way they have it. Even if they play the same what about the manufacturer's specifications in Strictly slots that usually give 40% or more for hit frequency for a 20-line game. What does 9 line do?

I also play the free Hot Shot Progressive offered by Bally on their web.. It's 20 lines and the line diagrams above 9 lines is quite a lot of area of hits compared to the regular 9 lines of past video slots. I am absolutely positive the one at the casino is 9 lines. Does this cut down on hit frequency? Why do this? Since the game was designed for 20 lines? Is this to cut down on the time possible to last on the machine? Low hit frequency makes more money come out on my pocket for comps than a higher hit frequency where more little longer lasting small wins could contribute to comps too. Comp dollars are something to think about too.


Dear Frank,

I don't know what your question to Casino Player was, but I'm not sure why they would recommend staying at a machine because of volatility. I suppose that your question was whether you should stay at a machine that isn't hitting. Your chances of hitting any winning combination are the same on every spin. No matter how volatile the machine, your chances of hitting something haven't changed just because the machine has been cold.

The Volatility Index doesn't tell a casino how much money it will earn from a machine. The long-term payback does that. The Volatility Index, instead, measures how bumpy a ride it will be to that long-term payback percentage. The casino doesn't really care about volatility because it has sufficient bankroll to see it through cold streaks (i.e., player hot streaks). It will take volatility into account, however, when ordering games because some players like volatile games and some don't. The casino will have a mix of low and high volatility machines on its slot floor.

Many multi-line machines can be configured to have, for example, 5, 9, 15 or 20 paylines. I don't know why Borgata configured their machines for only 9 paylines. Someone who wants to play nine lines and can play them on a 20-line machine, but someone who wants to play 20 lines can't play that many on a nine-line machine.

Decreasing the number of paylines does decrease the hit frequency, but it also decreases the risk, assuming the max bet per line stays the same. That would tend to make your bankroll last longer, not less time. Borgata didn't choose nine paylines to try to limit your time on the machines.

Best of luck in and out of the casinos,

Send your slot and video poker questions to John Robison, Slot Expert, at 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