Jul

14

2010

Estimating Jackpot Frequency on the Slots

Slot machines have been with us ever since Charles Fey invented the Liberty Bell slot in San Francisco in the 1890s. Those early slots were mechanical, and if you knew the number of symbols per reel, you could calculate the odds.

If a game had three reels with 10 symbols on each reel, and one top jackpot symbol per reel, then the odds of hitting the top jackpot were 1 in 10 x 10 z 10, or one in 1,000.

Today’s reel-spinners are computers in disguise, and there’s no calculating the odds at a glance. Programmers map symbols onto a virtual reel and a symbol that’s one of 20 on the physical reel can be made to behave as if its one of dozens, hundreds or thousands.

If the game design needs a virtual reel with 64 stops, then a programmer could specify that every time the random number generator produces No. 1, the reel will stop on the top jackpot symbol, every time it stops at Nos. 2 or 3,  the reel will stop on triple bars, and so on until all 64 numbers are associated with a symbol or space on the reel.

You can’t tell from the outside how many virtual stops there are on the virtual reel, so you can’t calculate slot odds at a glance. But you can take a loose hint from the size of the jackpot. Blazing 7s, with top payout of a thousand coins or so, will average a big hit every few thousand spins, while Megabucks pays its multimillions only about once per 50 million spins.