The clocks went back one hour on November 5, ending Daylight Saving Time (DST)—which runs from March to November—for another year. With the exception of Arizona, Hawaii, and some island territories, which don't recognize DST, most Americans got a little more sleep and a little less sunlight.
But is this annual spinning of the clocks actually a good idea? Is DST worth all the confusion over what time it is, the inconvenience?
DST dates back to Ben Franklin's time and has been championed by everyone from energy conservation experts to barbecue salesmen. Generally, the idea is to maximize sunlight hours when the weather's best, and to encourage commercial activity by keeping us spending longer into the evening. Lobbyists for retailers and the golf industry have been some of the most enthusiastic backers, according to this interesting history.
It may be that DST's commercial value is overplayed, though. An analysis by the JPMorgan Chase Institute (JPMCI), based on extensive credit card data, finds that DST spending increases when the period starts but falls by a greater amount when the period ends. The net spending effect is therefore negative, challenging the idea that DST is good for store owners and the leisure industry.
"There does seem to be some impact of an additional hour of sunlight on spending. But it ends up being a net negative impact," says Diana Farrell, CEO of the Institute.
JPMCI compared spending by 450,000 anonymized customers in Los Angeles (which observes DST) and Phoenix (which doesn't). In the 30 days following the start of DST, L.A. saw a 0.9% average increase over four years compared to Phoenix. But in 30 days following DST, it saw a 3.5% decline. The November drop-off was greatest on weekdays, presumably because opportunities to shop are greater on weekends, compensating for fewer daylight hours.
California's state Senate considered a bill to end DST earlier this year, but it was defeated. Research shows that switching over in March increases workplace injuries (because people are sleepier). But critics of the measure complained that unilaterally annulling DST would put California out of step with other states.
It may be that the commercial argument for DST doesn't hold up as well as people think, even if there are other reasons for keeping it. For one, it's nice to have longer summer evenings, shopping or not.