Why Daylight Saving Time is Good For Us

Because the sun will set an hour later this evening, we can all feel a bit safer.

Where are we going? To the cost and benefit of crime.

Daylight and Crime

In 2007, when the start of DST (Daylight Saving Time) changed from the first Sunday in April to the second Sunday in March, it created the perfect opportunity for two economists to compare crime statistics. Because the corresponding Fall change from the last Sunday in October to the second Sunday in November eliminated Halloween, they used only the Spring statistics.

The Results

Comparing the beginning of DST in 2005 and 2006 to 2007 and 2008, they concluded that criminal activity around sunset diminished by a whopping 27% while for the day it was down an average of 7%. In dollars, the reduced social cost from avoided robberies could be $42,310 per robbery or $59 million annually. And no, the criminal activity did not shift to the morning. I guess robbers, like me, are night owls.

If we actually did switch to perpetual DST, (below) you can see how sunrise and sunset would change. The rectangles shaded white indicate when we already have DST. The blue areas display the new times:

Our Bottom Line: The Cost and Benefit of Crime

Connecting cost, benefit, and crime, legendary behavioral economist and Nobel laureate Gary Becker (1930-2014) provided the springboard for the DST study.

Dr. Becker says he started thinking about crime on the Columbia University campus when he had to decide whether to park illegally or be late for a student’s oral exam in economic theory. As he describes, “I calculated the likelihood of getting a ticket, the size of the penalty, and the cost of putting the car in a lot. I decided it paid to take the risk and park on the street. (I did not get a ticket.)”

Breaking the law could mean you illegally parked, you robbed a house, or you played loud music. Very different violations, they all have one common denominator. Dr. Becker believed contemplating criminal behavior is a cost and benefit exercise:

1. We consider the probability and severity of the punishment.
2. We compare the utility of breaking the law to the utility of the next best alternative activity.

Using a classic Becker approach, the DST researchers hypothesize that the cost of crime goes up when there is daylight. During daylight a criminal can be identified more easily. Furthermore, since many of us leave work from 5 to 8 PM, there are extra people in the street that see the crime. It also means fewer hours (assumed because the number of crimes are down) are allocated to crime. Combine higher cost and fewer hours and you get a decrease in supply.

And an increase in safety from DST.

My sources and more: Having considered the history and dilemmas of DST from many angles in past posts, I was delighted to have discovered new information from Brookings and this paper on safety. Meanwhile a Washington Post article reminded me that my best source for DST info is always timeanddate.

Please note that several sentences in Our Bottom Line were in a previous econlife post.