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# Does Playing Several Slots at Once Make Any Sense?

27 July 1998

You've probably seen folks madly attacking multiple slot machines in tandem. Maybe you play this way. Does it make sense? Or is it more silly superstition among otherwise sane solid citizens?

To avoid comparing apples and oranges, picture this situation. 1) Imagine two or more identical machines. 2) Suppose equal total bets - maybe three \$1 tokens in a dollar machine, three 50-cent tokens at once in each of two half-dollar slots, four quarters together in each of three 25-cent units, and so forth.

Multiple slots neither lower nor raise inherent house advantage. Over a long period, casinos expect to earn the same fraction of what's bet regardless of how it's spread out. If slots hold an average of 5 percent of the money wagered, casinos anticipate \$5 per \$100 bet whether it's in one machine or a hundred.

Despite edge remaining constant, however, characteristics of the game experienced by each player change with multiple machines. I'll illustrate what this means in terms of a simplified device having the chances and payouts shown below. This machine returns 95 percent of the total bet, gives a 1 percent shot at winning a 50-for-1 jackpot, and comes up dry on 64 percent of all pulls.

 chance return 1.00% 50.0 10.00 2.0 25.00 1.0 64.00 0.0

What about betting half as much in each of two such slots? Combined returns are now as shown below.

 chance return 0.01% 50.0 0.20 26.0 0.50 25.5 1.28 25.0 1.00 2.0 5.00 1.5 19.05 1.0 32.00 0.5 40.96 0.0

The two machines still have 95 percent payback. But look at the payout breakdown. The probability of a 50-for-1 return - simultaneous bell-ringers - drops from 1 to 0.01 percent. The likelihood of at least one jackpot, a net return at least 25-for-1, adds up to 1.99 percent - nearly double that on one machine alone. For small scores, half a loaf might be too much sacrifice for twice the chance. With rich rewards, the greater odds could compensate for the lower multiple of the wager... \$50,000 winners rarely worry whether they got it betting \$1 or \$2.

There's also a shift at the opposite end of the luck spectrum. With two machines, pulls having total losses drop from 64 to 40.96 percent, although 32 percent of all rounds lose half a bet.

On three machines, return stays at 95 percent. Chances of three concurrent jackpots paying a total of 50-for-1 are a scant 0.0001 percent. But the probability of at least one jackpot is almost 3 percent and only 26.21 percent of all rounds will be washouts.

In typical sessions, bettors don't hit those low-probability high-payoff limo rides to Easy Street. Then, multiple machines moderate bankroll fluctuations - making players simultaneously less apt to win big and to go broke.

I'll put fluctuations into numerical terms. Say a player bets \$1 total at a time on one, two, or three of the hypothetical machines proposed above. Chances of being more than \$100 ahead or behind after 400 rounds are as follows.

 chance of being over \$100 ahead chance of being over \$100 behind 1 machine 14.6% 17.0% 2 machines 6.8 8.8 3 machines 3.0 4.4

As with most gambling options, the bottom line is the compromise that suits each individual's objectives. Playing multiple slots is a conservative strategy which may be appropriate for those who are happy to accept a modest win in return for a reduced chance of ripping through a bankroll. Sumner A Ingmark, who believes 21.4 percent of a sonnet is better than none, said it like this:

Those players who are not averse,
To small wins, may their risk disperse,
Forsaking fortune. Losing's worse.

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Best of Alan Krigman
Alan Krigman

Alan Krigman was a weekly syndicated newspaper gaming columnist and Editor & Publisher of Winning Ways, a monthly newsletter for casino aficionados. His columns focused on gambling probability and statistics. He passed away in October, 2013.
Alan Krigman
Alan Krigman was a weekly syndicated newspaper gaming columnist and Editor & Publisher of Winning Ways, a monthly newsletter for casino aficionados. His columns focused on gambling probability and statistics. He passed away in October, 2013.