On March 13, most North Americans will be setting their clocks forward an hour. But not all regions abide by daylight saving time, and many American states are currently considering scrapping it.

Werner Antweiler, an economist at the UBC Sauder School of Business, has investigated the pros and cons of daylight saving time and says there are plenty of good reasons not to do it.

Is it still worth it to change our clocks twice a year?

Ten years ago, the state of Indiana provided a natural experiment to gauge whether daylight saving time really does reduce energy use when it converted to DST statewide – and one study actually found a slight increase in energy demand after the switch. While there were savings on lighting, there was a larger increase in air conditioning use in long summer evenings and heating use in fall mornings. Empirical evidence really hasn’t found much in the way of benefits, but the costs are numerous.

What are the costs?


When the clocks go forward in March, a lot of people lose sleep. There has been plenty of evidence documenting a real and measurable cost of having a sleepy populace. Researchers have found a spike in motor vehicle accidents the Monday after clocks go back, and some evidence suggests there is an increase in fatalities which wouldn’t have occurred if clocks didn’t change. Psychologists have also found that springing forward can be bad for worker productivity, as people spend more time off-task on the first Monday of DST.

One study by UBC Sauder finance professor Maurice Levi found that DST shifts impact stock markets. While Mondays normally see a dip in stock returns, switching over to DST magnifies that dip by 200 to 500 per cent. Levi and his co-authors found the DST switch leads to a one-day loss of as much as $31 billion across all American stock exchanges. The DST stock-market continues to be researched actively.

Essentially, daylight saving time does not survive a rigorous cost-benefit analysis.

What should we do?

If we were to abolish daylight saving time, we have two choices: either have standard time year-round, or daylight saving time year-round—a question of whether the sun hits its peak around noon or around 1 p.m. It might actually be better to switch to year-round DST, with our days centered around 1 p.m., as new research suggests that would have optimal energy savings.

Prof. Antweiler regularly writes about a wide range of topics including economics, energy, the environment and public policy on his blog.

Top image source: Yuichi Tokutomi on Flickr.