After a Century of Daylight Saving Time, Its Benefits Are Still Unclear

March 10, 2018, 10:00 PM UTC

Some tonight, you will either manually set your clocks ahead an hour, or (more likely) your various smartphones, tablets, and computing devices will adjust themselves for you. Those devices will be carrying forward a practice that dates to March of 1918, when the U.S. — following Germany and Great Britain – implemented a plan for Daylight Saving Time.

The initial justification for the policy, implemented by Woodrow Wilson, was that it would save energy that could go towards helping fight World War I. The same rationale would be used for the expansion of Daylight Saving in later decades, including its national formalization in the 1960s.

Following World War I, though, a different rationale surfaced. According to Smithsonian Magazine, department store owners pushed for the policy to continue, since more people shopped after work when it was light out later. The policy has also benefited sports like golf.

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Those motives haven’t proven entirely durable. One study found that Daylight Savings actually increased home energy consumption and emissions, though a conflicting Department of Energy study found a small but significant decline. More damning was a 2016 J.P. Morgan study finding that, while there’s some boost to spending when Daylight Savings Time goes into effect, it’s offset by a substantial drop when clocks are switched back.

And Daylight Saving does not, contrary to widespread myth, particularly benefit farmers. In fact, farmers lobbied against it for decades.

So the commercial motives for Daylight Saving Time may not be all they’re cracked up to be. Some subtler positive effects have been measured, including declines in robberies – but so have increases in heart attacks and workplace accidents, thanks to the effects of sleep disruption.

On balance, the objective evidence against Daylight Saving Time seems to outweigh arguments in its favor. But groups lobbying to eliminate it have an uphill battle – polls in recent years show a majority of Americans still support the policy, even if it costs them sleep once a year.

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