How can this jackpot be random?

Dear Mr. Robison,

After reading many, many articles on the "as random as possible" aspect of RNG, I feel I have a good understanding of how it works. This being the case, I am stumped by one seemingly contrary occurrence and I hope you can explain it.

In various casinos -- Green Valley Ranch being one of them a few years back -- there were groups of slot machines that were "guaranteed" to hit prior to reaching a certain jackpot, say 50K. As the jackpot neared the promised payout figure, obviously more and more people showed up to play those certain machines. The jackpot did indeed hit as promised. How can this be reconciled with a software program/RNG where, technically, the jackpot could hit twice or more in one day or, conceivably, never hit at all during the life of the machine?

This has really been bugging me. Hopefully you can provide some clarity.

Thanks, Suzanne

Dear Suzanne,

Here's how these "guaranteed to hit" systems work.

The software in the controller administering the jackpot randomly chooses a value between the minimum and maximum values for the jackpot. As players spin the reels on the machines participating in the jackpot, the machines send signals to the controller indicating the amount bet on each spin. The software in the controller accumulates the amounts bet after multiplying them by a conversion factor. (The conversion factor is needed because the system can't award, for example, a $40,000 jackpot after only $40,000 has been played.) The player whose spin pushes the total in the controller over the jackpot value is awarded the jackpot.

If awarding the jackpot depended upon landing a combination on the payline, then it would be impossible to guarantee that it would hit before reaching a certain amount. Using the system I described, however, the jackpot can be awarded randomly and be guaranteed to hit within a specified range.

Best of luck in and out of the casinos,
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.