Today the sun is shining during my commute home from work. But this weekend, public service announcements will remind us to “fall back,” ending daylight saving time by setting our clocks an hour earlier on Sunday, Nov. 5. On Nov. 6, many of us will commute home in the dark. This semiannual ritual shifts our rhythms and temporarily makes us groggy at times when we normally feel alert. Moreover, many Americans are confused about why we spring forward in March and fall back in November, and whether it is worth the trouble. The practice of resetting clocks is not designed for farmers, whose plows follow the sun regardless of what time clocks say it is. And it does not create extra daylight — it simply shifts when the sun rises and sets relative to society’s regular schedule and routines. The key question is how people respond to this enforced shift. Most people have to be at work at a certain time — say, 8:30 a.m. — and if that time comes an hour earlier, they simply get up an hour earlier. The effect on society is another question. Here, the research shows that daylight saving time is more burden than boon. No energy savings Benjamin Franklin was one of the first thinkers to endorse the idea of making better use of daylight. Although he lived well before the invention of light bulbs, Franklin observed that people who slept past sunrise wasted more candles later in the evening. He also whimsically suggested the first policy fixes to encourage energy conservation: firing cannons at dawn as public alarm clocks, and fining homeowners who put up window shutters. To this day, our laws equate daylight saving with energy conservation. However, recent research suggests that it actually increases energy use. Poster celebrating enactment of daylight saving time during World War I, 1917. Credit: Library of Congress/Wikipedia This is what I found in a study co-authored with Yale economist Matthew Kotchen. We used a policy change in Indiana to estimate daylight saving time’s effects on electricity consumption. Prior to 2006, most Indiana counties did not observe it. By comparing households’ electricity demand before and after daylight saving time was adopted, month by month,