Why lines seems long may surprise you

Warning: After reading this article, you will never again stand in a line without thinking about how to make your wait time shorter.

Queuing theory is the mathematical science behind why the line is so long.

Of course there can be many reasons for a long line.

The most likely scenario is that you’re misunderstanding how the line is designed. Seeing a line snake back and forth across the width of a store three times can be deceiving as to how long you may actually have to wait. In what may appear to be a very long line, the service rate can be so good that the line moves very quickly.

This concept of system design rests on a mathematical theorem called Little’s Law.

It’s named after its creator, John Dutton Conant Little, an MIT professor who specializes in operations research.

Little’s Law provides the math that a researcher like me can use to check out different system designs employed in instances of waiting lines. It states that over time, the number of customers in a system is equal to their rate of arrival multiplied by the average time they spend in that system.

With the Little’s Law equation and my own stopwatch, I’ve proven over and over again that a longer line may actually be a better line. Let me explain.

Imagine a situation where you have many shorter lines, each being served by its own cashier. Call it the grocery store model, or the single-server model, more officially. You can get out of there quickly only if you correctly guess which line will move the quickest. And if you’re anything like me, you’re bound to bet on the wrong line.

But a single, longer line, being served by multiple employees – think banking, the motor vehicle department or airport security – is actually faster for everyone, even though it looks much longer than what you’re used to seeing in other systems.