The science of waiting lines

I hate waiting in lines. If I go to a restaurant that has anything more than 5 people waiting, I leave. The thought of queuing up outside a store for one of those big holiday sales is completely foreign to me. I often arrange my daily schedule to avoid waiting in lines: I drive in off-peak hours, eat when others are working, and avoid crowded shopping centers in favor of small locations.

The one thing more frustrating that waiting in a line is waiting in a bad line. You know, those lines that are poorly designed, without clear guidance about where to wait, or what you are waiting for. Or lines where it is clear that there are not enough services at the end (cashiers, clerks, or kiosks) to handle the number of people waiting.

What makes this so frustrating is that waiting lines don’t have to be so terrible. There is a science of waiting lines, and if organizations follow the science they can make their lines more efficient and more pleasant. Waiting times are a necessary evil. Having some form of a queue is often the best way to ensure that a system or service works as efficiently as it can. Queues make sure that each resource, be it a cashier or a customs official, never goes idle waiting for the next customer. Queues that are too long can drive customers away, but queues of the right length can increase efficiency and save money.

Donald Norman, a popular usability guru, has recently outlined some valuable design principles for making good waiting lines. Many of these are common sense, but when they are not followed the effects are usually obvious, and unpleasant.

One of the most important principles is that human emotions dominate the experience of waiting in lines, and that emotions are affected by context. Setting a pleasant context for a wait in a line can make all the difference. A location that is warm, bright, cheerful, and welcoming will be far better tolerated. This Disney theme parks, which are synonymous with long lines, are very good at setting a good context for a waiting line, often having costumed characters entertain people while they wait.

My son, who has more patience than me, recently got into one of those multi-hour waiting lines for a Boxing Day sale at an electronics store. The store did many things to make the wait as pleasant as possible: they gave out coffee and snacks, they gave people a number so they could take a break and return to the line, and they held raffles for free merchandise. This is also a good example of a related design principle: keep people occupied. Peoples’ perceptions of time and space are influenced by their surroundings. Many service environments, such as waiting rooms, now have TV’s and advertising displays to keep people occupied.

Emotions spread from person to person. So, in managing a good waiting line, it is important to watch for and address any negative emotions. This means paying attention to the most upset customers so that their negative emotions do not spread to the other people waiting in the line.

Another design principle is to eliminate confusion by making it clear and unambiguous where the line starts, where it ends, and how it works. Perhaps the worst waiting experience is finding out you have been waiting in the wrong line. Some of the best lines I have seen at airports are where one employee at the head of lines provides reassurance that people are entering the correct queue.

Providing feedback on how the line is progressing is also important. Nira Munichor and Anat Rafaeli from Isreal recently conducted a study of telephone waiting lines. They had participants either listen to music while they waited for a telephone service, or the people heard music and one of two spoken messages. The first message apologized for the wait and asked people to remain on the line. The second message provided information about where the person was in the line (e.g., “You are currently third in line”). Call abandonment rates (the frequency by which callers hang up) were 50% lower with the informative position information than with the music or apology conditions, and the customer experience was described as much better. It is possible to design good waiting lines, even for the telephone.

Waiting lines also need to be appropriate: long waits for trivial reasons or trivial goals won’t make any sense. Waits also have to seem fair. If there are a lot of people waiting and yet only a few service locations open, such as at a bank, then this appears to be unfair.

A lot can also be done to improve the waiting line experience by changing the way the line works. Certain kinds of layouts can make lines more efficient, faster, and therefor more pleasant. You may have seen cashier stations at cafeterias, for example, that have two sides for serving customers on the left and the right. This is because the process of cashing out a customer can be inefficient, with time spent while the customer puts items on the counter, finds money, packs up the items again, etc. While a customer is busy doing those things on one side, the cashier can serve another customer on the other side. For situations like this, this kind of arrangement makes the lines work much better.

Another example of changing the way a line works can be seen in drive-through restaurant windows. These restaurants often have one place for giving a food order, another place for paying for the food, and a third place for picking up the food. And, these windows are often far apart. This physical distance means that, as long as there are a few customers, there are built-in delays in the process. This is important because preparing the food takes time, but by designing the line in this way customers are seldom left waiting for their food to be prepared — by the time they have visited all the windows the food is ready.

Another design decision is having multiple servers with multiple lines, as is usually done in super markets, or multiple servers and one line, as is usually done in banks. One line can appear to move faster and appear more fair, and a single waiting line automatically adapts if one of the servers is slow or encounters an unusual circumstance (one of those people with dozens of coupons).

Of course, sometimes the best design is to avoid the line in the first place. Reservations are a method of avoiding waiting lines. I recently traveled to Europe and visited a number of museums and art galleries. I did a lot of research to make as many reservations as I could, even if it cost more, to avoid the lines. Even though every guide book I read explained how to do this, I was amazed at the thousands of people who ignored the advice and waited in line after line. If you get to Rome and want the visit the Vatican museum, make a reservation for one of their wonderful guided tours and don’t wait in the infamous lines (and don’t miss the Borghese Gallery, where you have to have a reservation).

Resources

Donald Norman, D. (2008.) The Psychology of waiting lines. http://www.jnd.org/dn.mss/the_psychology_of_waiting_lines.html

Munichor, N. & Rafaeli, A. (2007). Numbers or apologies? Customer reactions to telephone waiting time fillers. Journal of Applied Psychology, 92 (2), 511–518.

My favorite comedian, John Pinette, also hated waiting in lines:

http://www.youtube.com/watch?v=GUlf1F05gTA

2 thoughts on “The science of waiting lines

  1. Pingback: Over-Thinking the Line: Toy Story Mania | This is BANANAS

  2. Clive

    My favourite waiting line problem is at conference tea/coffee stations. Each beverage has a different proceedure, with different (multi-phase) waiting actions. Take Tea: select tea bag (slow), get hot water in cup (fast) put milk in cup (slow, but slightly fewer here that at hot water station, unless you are a ‘milk first’ person), put sugar in cup (slow, but fewer than milk station; some direct from hot water station).
    Most caterers put all the inputs on one table and people try to navigate the intense but variable waiting lines and work stations. Frustration for all.
    A better way? separate the stations. 3 places to choose tea bag, walk to hot water point (maybe 2, depending on numbers), then walk to sugar point and another walk to the very slow milk point. Only a few paces between them, but better flow is a result.

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