# Getting a Clue with Queuing Theory

I often find real world examples of process “improvements” staring me blatantly in the face. For example, I stumbled upon queuing theory in action at the local movie theatre.

Queuing theory is the study of how lines (or queues) are formed and dissipate over time. Examples of queues are everywhere: traffic at an intersection, restaurant lines during the lunch hour rush, dialing into a call center, etc. Queuing theory is a tool in the Lean Six Sigma tool kit. It aims reducing bottlenecks which contribute to time spent waiting in line (or in some cases, eliminating wait time completely).

Anyway, back to my experience at the move theatre… When I purchased tickets, I was asked if I wanted to sit in the front, middle, or back. I, like most of those attending the movie, chose the middle section. To my amazement, the ticket printed out an exact row and seat number (similar to what you would see on an airline ticket). As I took my seat, I saw how the rows in front of me and behind me suddenly filled up.

I can see where queuing theory could benefit the theatre from an efficiency and error proofing perspective. The computer knows exactly how many seats have been allocated to what movie and where in the screening room; a process that can assist in reducing the chance people from sneaking in to see an additional movie. In the movie I saw, occupied seating was concentrated to about 20% of the room, reducing clean up time for employees.

Although queuing might be efficient, is it always effective? In my case, the answer is no. Sure, I got to sit in the mid section as I requested. The saying “Be careful what you wish for” came to mind as I was surrounded in every imaginable direction by people. Given the option, I would have rather sat closer to (or even further away) from the screen if it meant I wasn’t breathing on top of the other movie goers. Further, if my husband and I had arrived a bit later and unknowingly requested middle seating, it is unlikely we would’ve been able to sit next to each other- a definite detractor of service.

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There are many applications where queuing has been successful such as automated computer screens which direct you to the next available bank clerk, checkout line, etc., however under these conditions most customers assume there won’t be a significant difference in their experience. But when there are multiple factors critical to quality (or in this case customer satisfaction), foregoing the voice of the customer can actually decrease customer satisfaction. The key here is being efficient and effective. A good Lean Six Sigma project will weigh voice of the customer or Kano analysis alongside forecasted cycle time improvements and determine what the net effect is prior to implementing a solution. If customer dissatisfaction outweighs process improvements, then your customers, if given a choice, will be less likely to purchase your products or services. In my case, I think I’ll be selecting a different theatre next time.