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# Are slots really random?

7 March 2013

A couple of years ago, I wrote a column on the theme, “If slots are really random …” It was sparked by readers who wondered how a casino exec could anticipate a big jackpot night if his games were random. The reason was simple: A big crowd meant more people playing, and more opportunities for both wins and losses.

But readers continue to ask about the randomness of slot machines, whether outcomes they’ve experienced refute the idea that the games are random. Let’s explore a couple of the ideas readers have floated past me.

“If slots are really random, how do you account for streaks? Sometimes I’ll be winning, and then the machine just goes ice cold. Maybe I’ll lose 20 or so times in a row before I either hit something or give up and change machines. I think the machine knows I’ve been winning, and decides to take it back.”

Streaks are a normal part of the probability of the game. Let’s take a three-reel game with a 12% hit frequency -- you’ll have a winner an average of once per 8.333 spins. On your first spin, there’s an 88% chance it’ll be a loser. There’s a 77% chance you’ll lose two in a row, 68% chance you’ll lose three in a row, and so on.

At 20 in a row, the number tossed out there by the reader who sent the e-mail, there’s still a 7.8% chance of every spin being a loser. That’s easily within normal probability. Anyone playing a machine with a 12% hit frequency for very long will have streaks of 20 or more losses.

Same deal if you’re counting the times between bonus events on a video slot machine. That’s something I like to do. In the same session, I’ve gone to the bonus round twice in a row, and had 100 plays between bonus events. Both the short turnaround and long cold snap grow out of the natural odds of the game.

Let’s say the odds of the game are set so the bonus event occurs an average of once per 30 spins, so you have a 3.333% chance of going to the bonus event on any given spin. By random chance, you have a 0.111% chance of going to the bonus twice in a row. That’s roughly once per 900 trials -- you won’t see it happen every time you play, but if you’re at the machine often enough, the bonus twins will happen.

What about going 100 times in a row without a bonus look? On our example game, there’s a 96.667% chance you won’t go to the bonus on any given spin. Two in a row with no bonus will happen 93.444% of the time, with percentages falling to 71.247% at 10 in a row, 18.358% at 50 in a row, and 3.370% at 100 in a row.

Note that the chances of going 100 spins in a row without a bonus are as good as the chances of getting the bonus on the next spin. There’s no need for a game “decide” to take anything back. Streaks -- with cold streaks longer than hot streaks -- are just a part of the normal odds of the game.

Some three-reel slots have hit frequencies higher or lower than 12%. Some video bonuses happen more than once per 30 spins, many happen less often. All games have streaks growing out of normal probability, and all are random.

“If slots are really random, why don’t I win more often? Shouldn’t winning symbols come up as often as losers?”

Sorry, no. “Random results” is not the same as saying “equal results.” A game doesn’t have to be programmed so that a jackpot symbol shows up as often as a blank space, or a bonus symbol as often as a cherry.

The odds of the game are set so that blank spaces will show up more often than winning symbols and small winners will show up more often than big winners. On three-reel slots, that will lead to there being more losing spins than winners, and on five-reel video games it will lead to more “wins” for amounts less than the size of your bet than bigger winners.

The programmer sets the odds of the game, then lets random chance take its course. When you play, may the chance be with you.

Look for John Grochowski on Facebook (http://tinyurl.com/7lzdt44) and Twitter (@GrochowskiJ).
Recent Articles
Best of John Grochowski
John Grochowski

John Grochowski is the best-selling author of The Craps Answer Book, The Slot Machine Answer Book and The Video Poker Answer Book. His weekly column is syndicated to newspapers and Web sites, and he contributes to many of the major magazines and newspapers in the gaming field, including Midwest Gaming and Travel, Slot Manager, Casino Journal, Strictly Slots and Casino Player.

Listen to John Grochowski's "Casino Answer Man" tips Tuesday through Friday at 5:18 p.m. on WLS-AM (890) in Chicago. Look for John Grochowski on Facebook and Twitter @GrochowskiJ.

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John Grochowski
John Grochowski is the best-selling author of The Craps Answer Book, The Slot Machine Answer Book and The Video Poker Answer Book. His weekly column is syndicated to newspapers and Web sites, and he contributes to many of the major magazines and newspapers in the gaming field, including Midwest Gaming and Travel, Slot Manager, Casino Journal, Strictly Slots and Casino Player.

Listen to John Grochowski's "Casino Answer Man" tips Tuesday through Friday at 5:18 p.m. on WLS-AM (890) in Chicago. Look for John Grochowski on Facebook and Twitter @GrochowskiJ.