daylight savings

Daylight Savings Time and Nominal Shocks

Nick Rowe has an excellent and timely post on DST and monetary policy:

Metrification was a nominal change that had negiligible real effects, as far as I know. Daylight Savings Time is a nominal change that has real effects. Some monetary changes, like currency reforms where we knock a couple of zeroes off the old currency and call it the new currency, are like metrification, where nothing real changes. And maybe all monetary changes are like metrification in the long run. But some monetary changes are like Daylight savings Time, and have real effects, at least in the short run.

If we understood Daylight Savings Time better, and how it works, we might understand monetary policy better.

Indeed, Nick makes some progress (slightly technical) on this question, read the whole thing for more.

A daylight savings time confession

Had the idea of a government plan to shift the clocks back and forth twice and year been proposed today I am reasonably certain that I would have been against it.  I probably would have argued that it would be chaotic, inefficient and unnecessary (private firms could agree with their employees to change working hours at any time, right?).  Central planning of time!  Washington bureaucracy messing with the clocks!  Get your government hands off my time!  

And yet, it works and I like it.  It is good to be reminded of this twice a year.

Daylight savings time increases energy usage

There is a natural experiment from the recent switch away from DST in Indiana.  Matthew Kotchen and Laura Grant report:

Our main finding is that–contrary to the policy’s intent–DST increases residential electricity demand. Estimates of the overall increase range from 1 to 4 percent, but we find that the effect is not constant throughout the DST period. There is some evidence of electricity savings during the spring, but the effect lessens, changes sign, and appears to cause the greatest increase in consumption near the end of the DST period in the fall. These findings are consistent with simulation results that point to a tradeoff between reducing demand for lighting and increasing demand for heating and cooling. Based on the dates of DST practice before the 2007 extensions, we estimate a cost of increased electricity bills to Indiana households of $8.6 million per year. We also estimate social costs of increased pollution emissions that range from $1.6 to $5.3 million per year.

In other words, with DST less is spent on light but more is spent on air conditioning.  Here is a summary article on the work, from today’s WSJ.  Do note this:

There may also be social benefits to daylight-saving time that weren’t covered in the research. When the extension of daylight-saving time was proposed by Mr. Markey, he cited studies that noted "less crime, fewer traffic fatalities, more recreation time and increased economic activity" with the extra sunlight in the evening.

Does daylight savings time kill people?

The new energy bill will give us an extra hour of daylight savings time for parts of both March and November.  But is this a good idea?  Is daylight savings time at all a good idea?  I don’t know, but here is a new argument I never heard before:

“Springing forward” is tantamount to imposing a mild case of jet lag throughout the country, with potentially unhappy consequences.

Might that mean more traffic accidents?

…following the spring shift to Daylight Savings Time (when one hour of sleep is lost) there is a measurable increase in the number of traffic accidents that result in fatalities. Furthermore, it replicates the absence of any “rebound” reduction of accidents following the fall shift to DST (when the opportunity is present for an additional hour of sleep).

Of the two competing hypotheses for this increase in accidents, namely the one that suggests that it is the increased sleep deficit that causes the change in accident rate, versus notions based upon reduced illumination levels when driving to work, or suppositions that people forget the DST time change, fail to adjust their clocks, and find themselves rushing to work to avoid being late, the sleep hypothesis seems to be the most tenable. Hypotheses based upon haste and dim morning light both predict the bulk of the increased accidents to be confined to the morning hours. The sleep loss hypothesis would predict that individuals become more tired as the day wears on and hence the bulk of the accidents will appear later in the day. It is, of course, this latter pattern which appears with most of the accident fatality increase confined to the period after noon.

If the sleep loss hypothesis is correct, then why isn’t there a reduction in the number of traffic accidents in the fall, when the shift back to standard time provides an extra hour for sleep? Although this was the pattern observed in one study (Coren, 1996b) it has not replicated in other studies. The failure of the “safety rebound” may simply have to do with human nature. Just because a person has the opportunity to sleep for an addition hour does not mean that people actually will go to sleep on time. Many may spend that extra hour socializing or watching television. In some instances, where individuals do go to bed at the appropriate time, their usual circadian rhythm may still wake them after 7 or 8 hours in response internal signals or the external morning increase in illumination. Contrast this to what happens in the spring, where an individual’s work schedule will enforce the person’s awakening on the new DST time in order to meet job commitments.

Here is a blog post (with further discussion) on the topic, here is the underlying study, the original tip is from Eric Rasmusen.  I have yet to see data on whether Indiana — which does not adopt Daylight Savings Time — is in fact a safer place to drive, at least for a part of each year.

Arguments to ponder for Thanksgiving

The population of wild koalas in the southeast portion of Australia’s Queensland state has plunged by 80% in less than two decades, but researchers are offering a simple plan to save them. They can sum it up in three words: daylight saving time.

Changing the clocks would help stem the koalapocalypse by reducing fatal encounters between koalas and the motorists who drive through their ever-shrinking territory, the researchers say. According to their calculations, the number of koala deaths could fall by 8% on weekdays and 11% on weekends.

“We hope that our study will encourage the Queensland government to consider the benefits of implementing DST,” they wrote in a study published Tuesday in the journal Biology Letters.

Queensland, the state in the northeastern corner of Australia, has a complicated relationship with daylight saving time. The practice has not been observed there since 3 a.m. on March 1, 1992, when a three-year trial period came to an end. The push to bring it back has spawned petitions, referendums and even a political party (Daylight Saving for South-East Queensland, or DS4SEQ).

There are too many noisy videos at the link.  And might abolishing the U.S. penny help the koalas too?  I am sure it will!

How many time zones does America need anyway?

Allison Schrager writes:

This year, Americans on Eastern Standard Time should set their clocks back one hour (like normal), Americans on Central and Rocky Mountain time do nothing, and Americans on Pacific time should set their clocks forward one hour. After that we won’t change our clocks again—no more daylight saving. This will result in just two time zones for the continental United States. The east and west coasts will only be one hour apart. Anyone who lives on one coast and does business with the other can imagine the uncountable benefits of living in a two-time-zone nation (excluding Alaska and Hawaii).

And why?:

It sounds radical, but it really isn’t. The purpose of uniform time measures is coordination. How we measure time has always evolved with the needs of commerce. According to Time and Date, a Norwegian Newsletter dedicated to time zone information, America started using four time zones in 1883. Before that, each city had its own time standard based on its calculation of apparent solar time (when the sun is directly over-head at noon) using sundials. That led to more than 300 different American time zones. This made operations very difficult for the telegraph and burgeoning railroad industry. Railroads operated with 100 different time zones before America moved to four, which was consistent with Britain’s push for a global time standard. The following year, at the International Meridian Conference, it was decided that the entire world could coordinate time keeping based on the British Prime Meridian (except for France, which claimed the Prime Median ran through Paris until 1911). There are now 24 (or 25, depending on your existential view of the international date line) time zones, each taking about 15 degrees of longitude.

Now the world has evolved further—we are even more integrated and mobile, suggesting we’d benefit from fewer, more stable time zones. Why stick with a system designed for commerce in 1883? In reality, America already functions on fewer than four time zones. I spent the last three years commuting between New York and Austin, living on both Eastern and Central time. I found that in Austin, everyone did things at the same times they do them in New York, despite the difference in time zone. People got to work at 8 am instead of 9 am, restaurants were packed at 6 pm instead of 7 pm, and even the TV schedule was an hour earlier.

There is more here.