Myriam B.C. Aries,
Guy R. Newsham, Energy Policy: Effect of daylight saving time on lighting
energy use: A literature review. The principal reason for introducing (and extending) daylight saving
time (DST) was, and still is, projected energy savings, particularly for
electric lighting. Simple estimates suggest a reduction in national electricity
use of around 0.5%, as a result of residential lighting reduction. Several
studies have demonstrated effects of this size based on more complex
simulations or on measured data. However, there are just as many studies that
suggest no effect, and some studies suggest overall energy penalties,
particularly if gasoline consumption is accounted for. There is general
consensus that DST does contribute to an evening reduction in peak demand for
electricity, though this may be offset by an increase in the morning.
Nevertheless, the basic patterns of energy use, and the energy efficiency of
buildings and equipment have changed since many of these studies were conducted.
Ryan Kellogg, Hendrik Wolff, IZA: Does Extending
Daylight Saving Time Save Energy? Evidence from an Australian Experiment. Several countries are considering extending Daylight
Saving Time (DST) in order to conserve energy, and the U.S. will extend DST by
one month beginning in 2007. However, projections that these extensions will
reduce electricity consumption rely on extrapolations and simulations rather
than empirical evidence. This paper, in contrast, examines a quasiexperiment in
which parts of Australia extended DST in 2000 to facilitate the Sydney Olympics.
Using detailed panel data and a triple differences specification, we show that
the extension did not conserve electricity, and that a prominent
simulation model overstates electricity savings when it is applied to
Australia.
Matthew J.
Kotchen, Laura E., VOX: Does daylight saving time save electricity? Daylight saving time, designed for energy
conservation purposes, is among the most widespread regulations on the planet.
Surprisingly little evidence exists that it actually saves energy. This column,
using a natural experiment, concludes that “saving” daylight has cost
electricity.
Christopher M.
Barnes David T. Wagner, NYT: The Economic Toll of Daylight Saving Time. In a study of mining injuries across the U.S., we
found a spike in workplace injuries of nearly 6 percent on the Monday following
the shift to daylight saving time. In a follow-up study we found that workers
tend to “cyberloaf” – that is, they use their computers and internet access to
engage in activities that are not related to work – at a substantially higher
rate on the Monday following the shift to daylight saving time than on other
Mondays. What’s more, we found that for every hour of interrupted sleep the
previous night, participants in our lab cyberloafed for 20 percent of their
assigned task. When extrapolated to a full day’s work, that would mean daylight
saving time and lost sleep can result in substantial productivity losses. In
fact, a recent estimate of this effect put the cost to the American economy at
over $434 million annually, simply from a subtle shift of the clocks.
Mark J. Kamstra,
Lisa A. Kramer, Maurice D. Levi, York University: Losing Sleep at the Market:
The Daylight-Savings Anomaly. We explore
the connection between equity returns and sleep disruptions following
daylight-savings time changes. In international markets, the average
Friday-to-Monday return on daylight-savings weekends is markedly lower than
expected, with a magnitude 200 to 500 percent larger than the average negative
return for other weekends of the year. This ``daylight-savings anomaly'' in
financial markets is consistent with desynchronosis research which has
identified the effects of changes in sleep patterns on judgment, anxiety, reaction
time, problem solving and accidents. This paper suggests sleep effects of
daylight-savings time changes may be impacting market participants
internationally.
Jin, L., Nicolas
Ziebarth, University of York: Sleep and Human Capital: Evidence from Daylight
Saving Time. This paper is one of the
first to test for a causal relationship between sleep and human capital. It
exploits the quasi-experimental nature of Daylight Saving Time (DST), up to 3.4
million BRFSS respondents from the US, and all 160 million hospital admissions
from Germany over one decade. We find evidence of mild negative health effects
when clocks are set forward one hour in spring. When clocks are set back one
hour in fall, effectively extending sleep duration for the sleep deprived by
one hour, sleep duration and selfreported health increase and hospital
admissions decrease significantly for four days.
Daniel Kuehnle,
Christoph Wunder, Friedrich-Alexander-University Erlangen-Nuremberg: Using the
life satisfaction approach to value daylight savings time transitions. Evidence
from Britain and Germany. Daylight savings
time (DST) represents a public good with costs and benefits. We provide the
first comprehensive examination of the welfare effects of the spring and autumn
transitions for the UK and Germany. Using individual-level data and a
regression discontinuity design, we estimate the effect of the transitions on
life satisfaction. Our results show that individuals in both the UK and Germany
experience deteriorations in life satisfaction in the first week after the spring
transition. We find no effect of the autumn transition. We attribute the
negative effect of the spring transition to the reduction in the time endowment
and the process of adjusting to the disruption in circadian rhythms. The
effects are particularly strong for individuals with young children in the
household. We conclude that the higher the shadow price of time, the more difficult
is adjustment. Presumably, an increase in flexibility to reallocate time could
reduce the welfare loss for individuals with binding time constraints.
Stanley Coren,
University of British Columbia: Daylight Savings Time and Traffic Accidents. We used data from a tabulation of all traffic
accidents in Canada as they were reported to the Canadian Ministry of Transport
for the years 1991 and 1992 by all 10 provinces. A total of 1,398,784 accidents
were coded according to the date of occurrence. The spring shift to daylight
savings time, and the concomitant loss of one hour of sleep, resulted in an
average increase in traffic accidents of approximately 8 percent, whereas the
fall shift resulted in a decrease in accidents of approximately the same
magnitude immediately after the time shift.
Tuuli Lahti, Esa
Nysten, Jari Haukka, Pekka Sulander, Timo Partonen, National Institute for
Health and Welfare: Daylight Saving Time Transitions and Road Traffic
Accidents. Circadian rhythm disruptions
may have harmful impacts on health. Circadian rhythm disruptions caused by jet
lag compromise the quality and amount of sleep and may lead to a variety of
symptoms such as fatigue, headache, and loss of attention and alertness. Even a
minor change in time schedule may cause considerable stress for the body.
Transitions into and out of daylight saving time alter the social and
environmental timing twice a year. According to earlier studies, this change in
time-schedule leads to sleep disruption and fragmentation of the circadian
rhythm. Since sleep deprivation decreases motivation, attention, and alertness,
transitions into and out of daylight saving time may increase the amount of
accidents during the following days after the transition.We studied the amount
of road traffic accidents one week before and one week after transitions into
and out of daylight saving time during years from 1981 to 2006. Our results
demonstrated that transitions into and out of daylight saving time did not increase
the number of traffic road accidents.
Cathleen D. Zick,
ISPAH: Does Daylight Savings Time Encourage Physical Activity? Extending Daylight Savings Time (DST) has been
identified as a policy intervention that may encourage physical activity.
However, there has been little research on the question of if DST encourages
adults to be more physically active. Data from residents of Arizona, Colorado,
New Mexico, and Utah ages 18–64 who participated in the 2003–2009 American Time
Use Survey are used to assess whether DST is associated with increased time
spent in moderate-to-vigorous physical activity (MVPA). The analysis
capitalizes on the natural experiment created because Arizona does not observe
DST. Both bivariate and multivariate analyses indicate that shifting 1 hour of
daylight from morning to evening does not impact MVPA of Americans living in
the southwest.
Jennifer L.
Doleac, Nicholas J. Sanders, University of Virginia: Under the Cover of
Darkness: How Ambient Light Influences Criminal Activity. We exploit daylight saving time (DST) as an exogenous
shock to daylight, using both the discontinuous nature of the policy and the
2007 extension of DST, to consider the impact of light on criminal activity.
Regression discontinuity estimates show a 7% decrease in robberies following
the shift to DST. As expected, effects are largest during the hours directly
affected by the shift in daylight. We discuss our findings within the context
of criminal decision making and labor supply, and estimate that the 2007 DST
extension resulted in $59 million in annual social cost savings from avoided
robberies.
Yvonne Harrison,
Sleep Medicine: The impact of daylight saving time on sleep and related
behaviours. Daylight saving time is
currently adopted in over 70 countries and imposes a twice yearly 1 h change in
local clock time. Relative ease in adjustment of sleep patterns is assumed by
the general population but this review suggests that the scientific data
challenge a popular understanding of the clock change periods. The start of
daylight saving time in the spring is thought to lead to the relatively
inconsequential loss of 1 h of sleep on the night of the transition, but data
suggests that increased sleep fragmentation and sleep latency present a cumulative
effect of sleep loss, at least across the following week, perhaps longer. The
autumn transition is often popularised as a gain of 1 h of sleep but there is
little evidence of extra sleep on that night. The cumulative effect of five
consecutive days of earlier rise times following the autumn change again
suggests a net loss of sleep across the week. Indirect evidence of an increase
in traffic accident rates, and change in health and regulatory behaviours which
may be related to sleep disruption suggest that adjustment to daylight saving
time is neither immediate nor without consequence.
Tuuli A Lahti et
al., BMC Physiology: Transitions into and out of daylight saving time
compromise sleep and the rest-activity cycles. Fall transition was more disturbing for the more morning type and
spring transition for the more evening type of persons. Individuals having a
higher global seasonality score suffered more from the transitions.Transitions
out of and into daylight saving time enhanced night-time restlessness and
thereby compromised the quality of sleep.
Imre Janszky et
al., Sleep Medicine: Daylight saving time shifts and incidence of acute
myocardial infarction – Swedish Register of Information and Knowledge About
Swedish Heart Intensive Care Admissions (RIKS-HIA). Daylight saving time shifts can be looked upon as
large-scale natural experiments to study the effects of acute minor sleep
deprivation and circadian rhythm disturbances. To identify AMI incidence on
specific dates, we used the Register of Information and Knowledge about Swedish
Heart Intensive Care Admission, a national register of coronary care unit
admissions in Sweden. We compared AMI incidence on the first seven days after
the transition with mean incidence during control periods. To assess effect
modification, we calculated the incidence ratios in strata defined by patient
characteristics. Overall, we found an elevated incidence ratio of 1.039 (95%
confidence interval, 1.003–1.075) for the first week after the spring clock
shift forward. The higher risk tended to be more pronounced among individuals
taking cardiac medications and having low cholesterol and triglycerides. There
was no statistically significant change in AMI incidence following the autumn
shift.
Imre Janszky,
Rickard Ljung: Karolinska Institute: Shifts to and from Daylight Saving Time
and Incidence of Myocardial Infarction. The incidence of acute myocardial infarction was significantly
increased for the first 3 weekdays after the transition to daylight saving time
in the spring. The incidence ratio for the first week after the spring shift,
calculated as the incidence for all 7 days divided by the mean of the weekly
incidences 2 weeks before and 2 weeks after, was 1.051 (95% confidence interval
[CI], 1.032 to 1.071). In contrast, after the transition out of daylight saving
time in the autumn, only the first weekday was affected significantly.
Rasmussen Report:
Just 33% See the Purpose of Daylight Saving Time. Only 33% of American Adults think DST is worth the
hassle, according to a 2014 national telephone survey. That is down from 37%
last year at this time and 45% in 2012. Forty-eight percent (48%) do not think
the clock changing ritual is worth it, but 19% are not sure.
Erika Hallhagen, SvD: Våga vägra sommartid. Så är den här.
Morgonmänniskornas högtid nummer ett. Dagen då de får beröva oss ännu en timme
skönhetssömn, trots att vi redan dansar efter deras pipa och börjar jobbet
långt innan vi är vakna. Här är sju argument som klargör varför ett
maktövertagande är det enda rätta. Det enda argumentet du behöver. Donald Trump
är morgonmänniska.
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