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Shopping Spree Jackpot at $4 Million Does it Have a Positive Expected Value?
At the time of this writing, the largest slot machine jackpot online is for the game Shopping Spree at Bovada. The jackpot has grown to $4,017,954 as of August 29, 2019. This page endeavors to estimate the probability of winning and the overall return of the game.
What We Know
According to our sister site, Casino Listings, we know the following:
- Current jackpot = $4,017,954*
- Bet required to qualify for jackpot = 9 lines at $1.25 each = $11.25 total bet
- Event required to qualify for jackpot = Five diamond rings on one of the nine paylines.
- Jackpot seed at $100,000.
- Jackpot has been hit once only before, for $1,244,529 on December 4, 2011.
*: As of August 29, 2019.
What We Assume
With rare exception, it is difficult to quantify the odds of slot machines. Sometimes casinos are kind enough to disclose the theoretical return percentage, but, unfortunately, Bovada does not.
That said, based on industry norms, I am going to assume the game has an overall return of 95%, on average, including the average value of the progressive.
The big question is what is the probability of hitting the jackpot per spin? To help answer that question, a forum member and I recorded 850 spins, recording how often a diamond ring appeared in any of the three positions on each reel. Here are my results:
Shopping Spree Sample Play
Also based on industry norms, I'm going to assume a 1.5% meter rise.
The way video slots generally work is there are reel strips of symbols. The game chooses a random number for each reel to determine where it stops on the reel and then displays those symbols to the player. It then pays the player according to whatever is on the screen.
If I simple assuming the probability of getting a Diamond Ring on any given reel is exactly equal to the number observed in the sample, then probability of betting a Diamond Ring on all five reels would be (83/850)×(68/850)×(64/850)×(86/850)×(88/850)× = 1 in 162311.
However, to win the jackpot, the five Diamond Rings must be on one of the nine active paylines. There are a total of 35 = 243 paylines. So the probability that five scattered Diamond Rings, with one per reel, fall on an active payline is 9/243 = 1 in 27. So, the overall probability of getting five Diamond Rings on an active payline is (1/162311) × (1/27) = 1 in 4,382,383.
At a current jackpot of $4,017,954 and a probability of winning of 1/4,382,383, the expected win from the jackpot per spin is 92 ¢. At a required bet of $11.25, the return from the jackpot is 8.15%.
As mentioned earlier, the jackpot was seeded at $100,000. The value of this to the player is $100,000 × 9 × (1/36)5/$11.25 = 0.13%. I also assume a meter rise of 1.5%. Assuming a total return of 95%, that would leave 95% - 0.13% - 1.5% = 93.37% for all other wins.
The bottom line is a value of 93.37% for the fixed wins and 8.15% for the progressive, which gets us to 101.45%. Of course, all this is based on some rough assumptions, so take my advice with a tablespoon of salt.
By the way, I show the break-even jackpot point to be $3,304,617.
- Casino Listings — Repository of data on Shopping Spree as well as many other progressive jackpots.
- Discussion about Shopping Spree in my forum at Wizard of Vegas.
- Play Shopping Spree for free at Bovada.
- Live US & Canada Slot Machine Jackpot Values and Graphs
Written by: Michael Shackleford