The Economic Toll of Daylight Saving Time

David T. Wagner is an assistant professor of organizational behavior and human resources at Singapore Management University. Christopher M. Barnes is an assistant professor of management and organization at the University of Washington.

March 6, 2014

Daylight saving time means it’s time to change the clocks and deal with the hassle of readjusting your body clock. Individuals may or may not like this meddling, but our research makes clear that businesses are hurt by it.

Our daily rhythm is largely driven by clocks, with many of us starting work at a given hour or trying to get children to school before the bell rings. Even though the clocks change at an innocuous time of day – 2 a.m. on Sunday – our bodies do not immediately adjust. Instead, most people wait to adjust until Sunday night and Monday morning, leaving them short on sleep by about 40 minutes when they go to work on Monday.

After the spring time change, there are more and worse workplace injuries, and workers tend to dawdle more on the Internet.

That may sound rather benign, but at least two of our studies highlight the organizational costs stemming from the loss. In a study of mining injuries across the U.S., we found a spike in workplace injuries of nearly 6 percent on the Monday following the shift to daylight saving time. An even greater cause for concern is that the severity of these injuries, as measured by days of work lost because of the injuries, increased by a whopping 67 percent, representing 2,600 more workdays lost, simply because of injuries experienced on that one day.

So the time change is bad for miners (and mining companies), but what about for the rest of us? In a follow-up study we found that workers tend to “cyberloaf” – that is, they use their computers and internet access to engage in activities that are not related to work – at a substantially higher rate on the Monday following the shift to daylight saving time than on other Mondays. What’s more, we found that for every hour of interrupted sleep the previous night, participants in our lab cyberloafed for 20 percent of their assigned task. When extrapolated to a full day’s work, that would mean daylight saving time and lost sleep can result in substantial productivity losses. In fact, a recent estimate of this effect put the cost to the American economy at over $434 million annually, simply from a subtle shift of the clocks. Unfortunately, we don’t regain that productivity when the fall change adds an hour to our schedules.

Given these findings, it’s increasingly clear that there are substantial business costs from the time change. In fact, we have conducted additional research that suggests workers with inadequate sleep are likely to be less ethical, less morally aware, more prejudiced and more apt to engage in abusive supervision. So does daylight saving time do more harm than good? We’ve seen substantial costs, without any benefit.