SINCE 2000 London has seen nearly 50 strikes on the Underground. The chaos which accompanies them is a short-term drag on the capital’s economy. The Federation of Small Businesses, an industry body, estimated that strikes in early February 2014 cost London £600m ($930m) in lost working hours, business and productivity. But a new paper by researchers at the universities of Oxford and Cambridge suggests that Tube strikes also have long-term benefits.

The focus of the paper is Londoners’ commuting patterns, before and after a work-stoppage takes place. It looks at the strikes in February last year, which two unions called in response to plans to close ticket offices and offer voluntary redundancies. The effect was that 171 of the Underground’s 270 stations closed for at least part of the strike. Some commuters were not much affected, whereas others were less lucky.

The authors compare the behaviour of commuters hit by the strike to those that were not. To do so, they gathered anonymised data from Oyster cards, the payment gizmos that Londoners use to enter and leave the Tube. They ended up with 20 days’ worth of data on 18,000 Londoners who used the Underground between 7am and 10am.

The results are surprising. Three-quarters of commuters were forced to change their route during the strike, either because stations were closed or because congestion was unbearable. But once the strike finished, not all of them went back to their old habits. Instead, about 5% of the group decided to stick with their new route.

Before the strike, it seems, many Londoners had unwittingly been taking a suboptimal route to work. The stylised Tube map, designed by Harry Beck in 1933, distorts London’s geography. Beck was pilloried for showing Wimbledon and South Wimbledon to be miles apart, when in fact it is an easy walk from one to the other. Add to that the different average speeds at which trains hurtle along—the Waterloo & City line goes at 47kph (29mph), compared with the Hammersmith & City line’s 15kph—and it is small wonder that many commuters choose the “wrong” route to work. The strike made them realise their mistake.

Following the strike, the authors find, commuters affected by it enjoyed on average a 20-second shorter trip. Over the subsequent four years, the authors estimate, the benefits of that shorter commute will be worth more than the time lost during the strike.