Comments on: Wait Time Psychology at Disneyland

By: William

William — Sun, 05 Apr 2015 15:42:54 +0000

Your equation is written in a confusing way and it seems wrong. It looks like you mean to divide lambda by the rest of the equation but that does not work. For lambda = 2 and mu = 1 the wait time woud come out to -2. If the (mu – lambda) is intended to be in the numerator rather than the denominator then the wait time would still comes out to -2 for these numbers. Either of those interpretations of the text gives a wrong answer because wait times can never be negative.

By: Laura Hamelin

Laura Hamelin — Tue, 11 Nov 2008 18:57:25 +0000

Hi everyone,
I really enjoyed this blog and I was wondering if anyone could help me. I am a fourth year business student and I have to provide simple calculations for average waiting time at one Disney World ride. The equation I am using is the exact same as the one first mentioned (it may not be
100% accurate but for the purpose of this class it is just right). Anyways, my problem is that I cannot find any statistics regarding number of arrivals or average number of customers who complete the ride in a given time period. If anyone could help it would be greatly appreciated!
Thanks in advance,
Laura

By: Ron G

Ron G — Thu, 08 May 2008 19:31:53 +0000

Hi, I enjoy your blog. I think James is correct that the equation you provide is not what Disney would use to calculate the waiting time. The equation you provide is ffor a M/M/1 queue, which has alot of assumptions including steady-state, Poisson interarrival times, and Poisson service times. Living in Florida and having been to Disney World several times I would say the variation in service times is low for many attractions due to the way they stage guests in front of the rides. While not deterministic, it is close. Also, I would guess the arrival rate for most attractions is usually greater than the service rate during peak times of the day for these attractions (so lambda > mu). In other words, the system is not in steady-state, and therefore the equation is not valid.

By: psabilla

psabilla — Fri, 20 Apr 2007 20:15:39 +0000

@James,

No, that is definitely the equation used to calculate average wait time.

Comfort — good point, but it helps to be honest, though. Honesty has the added effect of building trust that the average wait time is approximately correct. If a lower number than the actualy calcualated number was shown, it would most likely build distrust in customers because after x time has passed, the line still has more to go before the customer is served. Plus, it’s just good business to be honest.

By: james

james — Mon, 26 Mar 2007 20:30:25 +0000

Hey Peter,

I don’t think they used that formula for that approx wait time. I would imagine that it would be as simple as knowing how many people on average can fit into the physical line and knowing the service time.

I agree that it is really comforting knowing what the wait time will be and even more comforting when that wait time is actually shorter than shown!

By: Peter

Peter — Mon, 26 Mar 2007 15:56:38 +0000

Last week I was at a seminar featuring the very lean guy John Bicheno, and he told a similar story about the psychology of queueing. He told that elevator manufacturers knows that people hate standing in line at elevators, but that almost disappear if a mirror is introduced. Suddenly there is something to do while standing around waiting. It seems simple, yet very powerfull.