To Pick the Fastest Line, Follow People With the Most Items

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Photo: Chris Ratcliffe/Bloomberg via Getty Images

Whether you call it standing in or on line, queues are a part of life in New York City: snaking around Trader Joe’s, piling up behind the security check at LaGuardia, awaiting the next cronut. MIT engineering systems professor Richard Larson estimates that Americans spend 37 billion hours waiting in line a year, and surely New Yorkers are responsible for a huge chunk of that.

But one need not go gentle into that good line; there are strategies, such as those recently reported out by Christopher Mele for the New York Times, for reducing wait times. The strategy that’s the most beguiling is also the most counterintuitive: Find the shopper (or shoppers) with the fullest cart(s), and get behind them.

That’s because, according to research, in a given grocery-store queue, it will take an average of 41 seconds for each person to get through, while every individual item requires three seconds or so. The number of items in question is the variable cost between every person in line, while the fixed cost is in the social rituals involved in getting through the checkout. “Every person requires a fixed amount of time to say hello, pay, say good-bye, and clear out of the lane,” explains Dan Meyer, the chief academic officer at the education startup Demos.

It all goes back to Little’s Law, the golden rule when it comes to queues. It states that the length of a queue is equal to how long each interaction takes times the number of people or things coming in. So if you opt for a line of lots of people with few things, fixed costs stack up with each additional person, but if you park yourself in a line with fewer people with more items, the fixed costs are kept low, and you can get through quicker — even if their carts are piled higher.