Editing Daylight saving time (section)

== Effects ==
{{Main|Analysis of daylight saving time}}

=== Effects on electricity consumption ===
[[File:William-Willett.jpg|thumb|right|upright|alt=A standing man in three-piece suit, facing camera. He is about 60 and is bald with a mustache. His left hand is in his pants pocket, and his right hand is in front of his chest, holding his pocket watch.|[[William Willett]] independently proposed DST in 1907 and advocated it tirelessly.{{sfnp|''Seize the Daylight''|2005|p=22}}]]
Proponents of DST generally argue that it saves energy, promotes outdoor leisure activity in the evening (in summer), and is therefore good for physical and psychological health,<ref>{{cite journal | vauthors = Goodman, A, Page, A, Cooper, A | title = Daylight saving time as a potential public health intervention: an observational study of evening daylight and objectively-measured physical activity among 23,000 children from 9 countries|journal = International Journal of Behavioral Nutrition and Physical Activity| date = 23 October 2014| volume = 11| page = 84| doi = 10.1186/1479-5868-11-84| pmid = 25341643| pmc = 4364628| s2cid = 298351| doi-access = free}}</ref> reduces traffic accidents, reduces crime or is good for business.<ref name="CBC News-2020">{{Cite news|title=Tired of turning clocks forward and back? You have big business to thank|language=en-US|work=CBC News|url=https://www.cbc.ca/news/business/daylight-saving-business-energy-1.3485281|access-date=4 December 2020|archive-date=4 December 2020|archive-url=https://web.archive.org/web/20201204142613/https://www.cbc.ca/news/business/daylight-saving-business-energy-1.3485281|url-status=live}}</ref> Opponents argue the actual energy savings are inconclusive.<ref>{{Citation| last=Choi| first=Charles| year=2009| title=Does Daylight Saving Time Conserve Energy?| publisher=Scientific American| publication-place =New York, NY, USA| url =https://www.scientificamerican.com/article/does-daylight-saving-times-save-energy/| archive-url  =https://web.archive.org/web/20140130232223/https://www.scientificamerican.com/article/does-daylight-saving-times-save-energy/ |archive-date=30 January 2014}}</ref>

Although energy conservation goals still remain under certain conditions,<ref name="Ahuja">{{cite journal|author1=Dilip R. Ahuja|author2=D. P. Sen Gupta|author3=V. K. Agrawal|year=2007|title=Energy savings from advancing the Indian Standard Time by half an hour|url=http://www.currentscience.ac.in/Downloads/article_id_093_03_0298_0302_0.pdf|journal=Current Science|volume=93|issue=3|pages=298–302|access-date=20 August 2013|archive-date=1 February 2014|archive-url=https://web.archive.org/web/20140201233923/http://www.currentscience.ac.in/Downloads/article_id_093_03_0298_0302_0.pdf|url-status=live}}</ref> energy usage patterns have greatly changed since then. In a publication from 2025, based on this change in consumption patterns, such as air conditioning systems, additional consumption is expected to occur more frequently during daylight saving time in the future.<ref name="Neumann">{{cite journal | last1 = Neumann | first1 = Philipp | last2 = Blanckenburg | first2 = Korbininan von | title = What Time Will It Be? A Comprehensive Literature Review on Daylight Saving Time | journal = Time & Society | date = 2025 | doi = 10.1177/0961463X241310562 | url = https://journals.sagepub.com/oi/10.1177/0961463X241310562 | access-date = 2 March 2025}}</ref> Electricity use is greatly affected by geography, climate, and economics, so the results of a study conducted in one place may not be relevant to another country or climate.<ref name="Aries" /> Nevertheless, while overall electricity usage does not decrease, the evening peak demand is flattened, which in turn has a direct impact on generation costs.<ref name="Neumann"/>

A 2017 meta-analysis of 44 studies found that DST leads to electricity savings of 0.3% during the days when DST applies.<ref name="Havranek">{{Cite journal|last1=Havranek|first1=Tomas|last2=Herman|first2=Dominik|last3=Irsova|first3=Zuzana|date=1 June 2018|title=Does Daylight Saving Save Electricity? A Meta-Analysis|journal=The Energy Journal|language=en-US|volume=39|issue=2|pages=35–61 |doi=10.5547/01956574.39.2.thav|bibcode=2018EnerJ..39...35H |issn=1944-9089|s2cid=58919134}}</ref><ref name="Irsova - Doesn't">{{Cite web|last1=Irsova|first1=Zuzana|last2=Havranek|first2=Tomas|last3=Herman|first3=Dominik|date=2 December 2017|title=Daylight saving saves no energy|url=http://voxeu.org/article/daylight-saving-saves-no-energy|access-date=2 December 2017|website=VoxEU.org|archive-date=3 December 2017|archive-url=https://web.archive.org/web/20171203153846/http://voxeu.org/article/daylight-saving-saves-no-energy|url-status=live}}</ref> Several studies have suggested that DST increases motor fuel consumption,<ref name="Aries">{{cite journal|author1=Myriam B.C. Aries|author2=Guy R. Newsham|year=2008|title=Effect of daylight saving time on lighting energy use: a literature review|url=https://nrc-publications.canada.ca/eng/view/accepted/?id=19fb83b6-0f6b-4d94-a1a9-6854b57c9dfd|journal=Energy Policy|volume=36|issue=6|pages=1858–1866|doi=10.1016/j.enpol.2007.05.021|access-date=25 September 2019|archive-date=26 October 2019|archive-url=https://web.archive.org/web/20191026141756/https://nrc-publications.canada.ca/eng/view/accepted/?id=19fb83b6-0f6b-4d94-a1a9-6854b57c9dfd|url-status=live}}</ref> but a 2008 [[United States Department of Energy]] report found no significant increase in motor gasoline consumption due to the 2007 United States extension of DST.<ref name="DOE-2008">{{cite report|url=http://www1.eere.energy.gov/analysis/pdfs/epact_sec_110_edst_report_to_congress_2008.pdf|title=Impact of Extended Daylight Saving Time on national energy consumption: report to Congress, Energy Policy Act of 2005, Section 110|author1=David B. Belzer|author2=Stanton W. Hadley|publisher=US Dept. of Energy|author3=Shih-Miao Chin|archive-url=https://web.archive.org/web/20130518104926/http://www1.eere.energy.gov/analysis/pdfs/epact_sec_110_edst_report_to_congress_2008.pdf|year=2008|url-status=dead|archive-date=18 May 2013}}</ref> An early goal of DST was to reduce evening usage of [[incandescent lighting]], once a primary use of electricity.<ref name="Bartlett">{{cite book|author=Roscoe G. Bartlett|title=Energy Conservation Potential of Extended and Double Daylight Saving Time|date=24 May 2001|series=Serial 107-30|chapter=Statement to the US House, Committee on Science, Subcommittee on Energy|author-link=Roscoe G. Bartlett|chapter-url=http://commdocs.house.gov/committees/science/hsy73325.000/hsy73325_0.HTM|access-date=11 March 2007|archive-date=25 August 2007|archive-url=https://web.archive.org/web/20070825165703/http://commdocs.house.gov/committees/science/hsy73325.000/hsy73325_0.htm|url-status=live}}</ref>

===Economic effects===
It has been argued that clock shifts correlate with decreased [[economic efficiency]] and that in 2000, the daylight-saving effect implied an estimated one-day loss of $31 billion on US stock exchanges.<ref>{{cite journal|author1=Mark J. Kamstra|author2=Lisa A. Kramer|author3=Maurice D. Levi|year=2000|title=Losing sleep at the market: the daylight saving anomaly|url=http://homes.chass.utoronto.ca/~lkramer/aer-daylightsaving-reply.pdf|journal=American Economic Review|volume=90|issue=4|pages=1005–1011|citeseerx=10.1.1.714.2833|doi=10.1257/aer.90.4.1005|access-date=27 October 2017|archive-date=21 September 2017|archive-url=https://web.archive.org/web/20170921234625/http://homes.chass.utoronto.ca/~lkramer/aer-daylightsaving-reply.pdf|url-status=live}}</ref> Others have asserted that the observed results depend on methodology<ref>{{cite journal|author1=Luisa Müller|author2=Dirk Schiereck|author3=Marc W. Simpson|author4=Christian Voigt|year=2009|title=Daylight saving effect|journal=Journal of Multinational Financial Management|volume=19|issue=2|pages=127–138|doi=10.1016/j.mulfin.2008.09.001}}</ref> and disputed the findings,<ref>{{cite journal|author=Michael J. Pinegar|year=2002|title=Losing sleep at the market: Comment|journal=American Economic Review|volume=92|issue=4|pages=1251–1256|doi=10.1257/00028280260344786|jstor=3083313|s2cid=16002134}}</ref> though the original authors have refuted points raised by disputers.<ref>{{cite journal|author1=Mark J. Kamstra|author2=Lisa A. Kramer|author3=Maurice D. Levi|year=2002|title=Losing sleep at the market: the daylight saving anomaly: Reply|journal=American Economic Review|volume=92|issue=4|pages=1257–1263|doi=10.1257/00028280260344795|jstor=3083314}}</ref>

=== Effects on health ===
There are measurable adverse effects of clock-shifts on human health.<ref>{{Cite journal |last1=Zhang |first1=H. |last2=Khan |first2=A. |last3=Edgren |first3=G. |last4=Rzhetsky |first4=A. |date=8 June 2020 |title=Measurable health effects associated with the daylight saving time shift. |journal=PLOS Comput. Biol. |volume=16 |issue=6 |pages=e1007927 |doi=10.1371/journal.pcbi.1007927|pmid=32511231 |pmc=7302868 |bibcode=2020PLSCB..16E7927Z |doi-access=free }}</ref> It has been shown to disrupt human [[circadian rhythm]]s,<ref>{{Cite journal |last1=Rishi |first1=M. A. |last2=Ahmed |first2=O. |last3=Barrantes Perez |first3=J. H. |last4=Berneking |first4=J. |last5=Flynn-Evans |first5=E. E. |last6=Gurubhagavatula |first6=I. |title=Daylight saving time: an American Academy of Sleep Medicine position statement |journal=Journal of Clinical Sleep Medicine |year=2020 |volume=16 |issue=10 |pages=1781–1784|doi=10.5664/jcsm.8780 |pmid=32844740 |pmc=7954020 }}</ref> negatively affecting human health in the process,<ref name="Roenneberg June 2019">{{cite journal|vauthors=Roenneberg T, Wirz-Justice A, Skene DJ, Ancoli-Israel S, Wright KP, Dijk DJ, Zee P, Gorman MR, Winnebeck EC, Klerman EB|date=2019|title=Why Should We Abolish Daylight Saving Time?|journal=Journal of Biological Rhythms|volume=34|issue=3|pages=227–230|doi=10.1177/0748730419854197|pmc=7205184|pmid=31170882|doi-access=free}}</ref> and that the yearly DST clock-shifts can increase health risks such as heart attacks<ref name="NatGeo Time" /> and traffic accidents.<ref>{{Cite journal |last1=Fritz |first1=Josef |last2=VoPham |first2=Trang |last3=Wright |first3=Kenneth P. |last4=Vetter |first4=Céline |date=February 2020 |title=A Chronobiological Evaluation of the Acute Effects of Daylight Saving Time on Traffic Accident Risk |journal=Current Biology |volume=30 |issue=4 |pages=729–735.e2 |doi=10.1016/j.cub.2019.12.045 |pmid=32008905 |s2cid=210956409 |issn=0960-9822|doi-access=free |bibcode=2020CBio...30E.729F }}</ref><ref>{{Cite journal |last1=Orsini|first1=Federico|last2=Zarantonello|first2=Lisa|last3=Costa|first3=Rodolfo |last4=Rossi|first4=Riccardo |last5=Montagnese|first5=Sara| date=July 2022 |title=Driving simulator performance worsens after the Spring transition to Daylight Saving Time |journal=iScience |volume=25 |issue=7 |pages=104666 |doi=10.1016/j.isci.2022.104666 |pmid=35811844 |pmc=9263509 |bibcode=2022iSci...25j4666O |issn=2589-0042}}</ref>

A 2017 study in the ''[[American Economic Journal|American Economic Journal: Applied Economics]]'' estimated that "the transition into DST caused over 30 deaths at a social cost of $275 million annually", primarily by increasing sleep deprivation.<ref>{{Cite journal |last=Smith |first=Austin C. |date=2016 |title=Spring Forward at Your Own Risk: Daylight Saving Time and Fatal Vehicle Crashes |journal=American Economic Journal: Applied Economics |language=en |volume=8 |issue=2 |pages=65–91 |citeseerx=10.1.1.676.1062 |doi=10.1257/app.20140100 |issn=1945-7782}}</ref>

A correlation between clock shifts and increase in traffic accidents has been observed in North America and the UK but not in Finland or Sweden.<ref>{{cite journal |last1=Fritz |first1=Josef |date=2020 |title=A Chronobiological Evaluation of the Acute Effects of Daylight Saving Time on Traffic Accident Risk |journal=Current Biology |volume=30 |issue=4 |pages=729–735.e2 |doi=10.1016/j.cub.2019.12.045 |pmid=32008905 |doi-access=free |bibcode=2020CBio...30E.729F |s2cid=210956409}}</ref> Four reports have found that this effect is smaller than the overall reduction in traffic fatalities.<ref>{{cite journal |author1=Jason Varughese |author2=Richard P. Allen |year=2001 |title=Fatal accidents following changes in daylight savings time: the American experience |journal=Sleep Medicine |volume=2 |issue=1 |pages=31–36 |doi=10.1016/S1389-9457(00)00032-0 |pmid=11152980}}</ref><ref>{{cite journal |author1=J. Alsousoua |author2=T. Jenks |author3=O. Bouamra |author4=F. Lecky |author5=K. Willett |year=2009 |title=Daylight savings time (DST) transition: the effect on serious or fatal road traffic collision related injuries |journal=Injury Extra |volume=40 |issue=10 |pages=211–212 |doi=10.1016/j.injury.2009.06.241 |doi-access=free}}</ref><ref>
{{cite journal |author1=Tuuli A. Lahti |author2=Jari Haukka |author3=Jouko Lönnqvist |author4=Timo Partonen |year=2008 |title=Daylight saving time transitions and hospital treatments due to accidents or manic episodes |journal=BMC Public Health |volume=8 |page=74 |doi=10.1186/1471-2458-8-74 |pmc=2266740 |pmid=18302734 |doi-access=free }}</ref><ref>{{cite journal |author1=Mats Lambe |author2=Peter Cummings |year=2000 |title=The shift to and from daylight savings time and motor vehicle crashes |journal=Accident Analysis & Prevention |volume=32 |issue=4 |pages=609–611 |doi=10.1016/S0001-4575(99)00088-3 |pmid=10868764}}</ref> According to data shared by Titan Casket, hospitals see a 24% increase in heart attacks<ref>{{Cite journal |last1=Sandhu |first1=Amneet |last2=Seth |first2=Milan |last3=Gurm |first3=Hitinder S. |date=1 March 2014 |title=Daylight savings time and myocardial infarction |journal=Open Heart |language=en |volume=1 |issue=1 |pages=e000019 |doi=10.1136/openhrt-2013-000019 |issn=2053-3624 |pmc=4189320 |pmid=25332784}}</ref> and a 6% increase in fatal crashes<ref>{{Cite journal |last1=Fritz |first1=Josef |last2=VoPham |first2=Trang |last3=Wright Jr. |first3=Kenneth P. |last4=Vetter |first4=Céline |date=30 January 2020 |title=A Chronobiological Evaluation of the Acute Effects of Daylight Saving Time on Traffic Accident Risk |journal=Current Biology |volume=30 |issue=4 |pages=729–735.e2 |bibcode=2020CBio...30E.729F |doi=10.1016/j.cub.2019.12.045 |pmid=32008905 |doi-access=free}}</ref> each year when the time changes. In 2018, the [[European Parliament]], reviewing a possible abolition of DST, approved a more in-depth evaluation examining the disruption of the human body's circadian rhythms which provided evidence suggesting the existence of an association between DST clock-shifts and a modest increase of occurrence of acute myocardial infarction, especially in the first week after the spring shift.<ref>{{Cite journal |last1=Manfredini |first1=F. |last2=Fabbian |first2=F. |last3=Cappadona |first3=R. |date=2018 |title=Daylight saving time, circadian rhythms, and cardiovascular health |journal=Internal and Emergency Medicine |volume=13 |issue=5 |pages=641–646 |doi=10.1007/s11739-018-1900-4|pmid=29971599 |pmc=6469828 }}</ref> However a Netherlands study found, against the majority of investigations, contrary or minimal effect.<ref>{{Cite journal |last1=Derks |first1=L. |last2=Houterman |first2=S. |last3=Geuzebroek |first3=G.S.C. |title=Daylight saving time does not seem to be associated with number of percutaneous coronary interventions for acute myocardial infarction in the Netherlands |journal=Netherlands Heart Journal |year=2021 |volume=29 |issue=9 |pages=427–432 |doi=10.1007/s12471-021-01566-7|pmid=33765223 |pmc=8397810 }}</ref> Year-round standard time (not year-round DST) is proposed by some to be the preferred option for public health and safety.<ref name="The Globe and Mail">{{cite news|last1=Cermakian|first1=Nicolas|title=Turn back the clock on Daylight Savings: Why Standard Time all year round is the healthy choice|url=https://www.theglobeandmail.com/opinion/article-turn-back-the-clock-on-daylight-savings-why-standard-time-all-year/|newspaper=The Globe and Mail|date=2 November 2019|access-date=4 March 2020|archive-date=20 October 2020|archive-url=https://web.archive.org/web/20201020004547/https://www.theglobeandmail.com/opinion/article-turn-back-the-clock-on-daylight-savings-why-standard-time-all-year/|url-status=live}}</ref><ref name="The Sacramento Bee">{{cite web|last1=Block|first1=Gene|title=Who wants to go to work in the dark? Californians need Permanent Standard Time|url=https://chancellor.ucla.edu/writings-speeches/wants-go-work-dark-californians-need-permanent-standard-time/|publisher=The Sacramento Bee|access-date=4 March 2020|archive-date=4 March 2020|archive-url=https://web.archive.org/web/20200304052801/https://chancellor.ucla.edu/writings-speeches/wants-go-work-dark-californians-need-permanent-standard-time/|url-status=live}}</ref><ref name="U Calgary News">{{cite web|last1=Antle|first1=Michael|title=Circadian rhythm expert argues against permanent daylight saving time|date=30 October 2019|url=https://www.ucalgary.ca/news/circadian-rhythm-expert-argues-against-permanent-daylight-saving-time|publisher=U Calgary News|access-date=4 March 2020|archive-date=4 March 2020|archive-url=https://web.archive.org/web/20200304052759/https://www.ucalgary.ca/news/circadian-rhythm-expert-argues-against-permanent-daylight-saving-time|url-status=live}}</ref><ref name="CBC News">{{cite news|date=31 October 2019|title=Year-round daylight time will cause 'permanent jet lag,' sleep experts warn in letter to government|publisher=CBC News|url=https://www.cbc.ca/news/canada/british-columbia/daylight-time-bc-sleep-experts-1.5342620|access-date=4 March 2020|archive-date=8 March 2021|archive-url=https://web.archive.org/web/20210308200121/https://www.cbc.ca/news/canada/british-columbia/daylight-time-bc-sleep-experts-1.5342620|url-status=live}}</ref><ref>{{cite journal|last1=Barnes|first1=Christopher M.|last2=Drake|first2=Christopher L.|date=November 2015|title=Prioritizing Sleep Health|journal=Perspectives on Psychological Science|volume=10|issue=6|pages=733–737|doi=10.1177/1745691615598509|pmid=26581727|doi-access=free}}</ref> Clock shifts were found to increase the risk of heart attack by 10 percent,<ref name="NatGeo Time" /> and to disrupt sleep and reduce its efficiency.<ref name="Lahti">{{cite journal|author1=Tuuli A. Lahti|author2=Sami Leppämäki|author3=Jouko Lönnqvist|author4=Timo Partonen|year=2008|title=Transitions into and out of daylight saving time compromise sleep and the rest–activity cycles|journal=BMC Physiology|volume=8|page=3|doi=10.1186/1472-6793-8-3|pmc=2259373|pmid=18269740 |doi-access=free }}</ref> Effects on seasonal adaptation of the [[circadian rhythm]] can be severe and last for weeks.<ref>DST and circadian rhythm:
*{{cite journal|author1=Pablo Valdez|author2=Candelaria Ramírez|author3=Aída García|year=2003|title=Adjustment of the sleep–wake cycle to small (1–2h) changes in schedule|journal=Biological Rhythm Research|volume=34|issue=2|pages=145–155|doi=10.1076/brhm.34.2.145.14494|bibcode=2003BioRR..34..145V |s2cid=83648787}}
*{{cite journal|author1=Thomas Kantermann|author2=Myriam Juda|author3=Martha Merrow|author4=Till Roenneberg|author4-link=Till Roenneberg|year=2007|title=The human circadian clock's seasonal adjustment is disrupted by daylight saving time|url=https://pure.rug.nl/ws/files/6711968/2007CurrBiolKantermann.pdf|journal=Current Biology|volume=17|issue=22|pages=1996–2000|doi=10.1016/j.cub.2007.10.025|pmid=17964164 |bibcode=2007CBio...17.1996K |s2cid=3135927|access-date=6 June 2020|archive-date=16 November 2020|archive-url=https://web.archive.org/web/20201116060505/https://pure.rug.nl/ws/files/6711968/2007CurrBiolKantermann.pdf|url-status=live}}
*{{cite news |date=25 October 2007 |title=Daylight saving hits late risers hardest |work=ABC News |location=Australia |url=http://www.abc.net.au/science/news/stories/2007/2070223.htm}}</ref>

=== Effects on social relations ===
DST hurts prime-time television broadcast ratings,<ref name="Kissell">{{cite news|author=Rick Kissell|date=20 March 2007|title=Daylight-saving dock ratings|work=Variety|url=https://variety.com/2007/scene/markets-festivals/daylight-saving-dock-ratings-1117961488/|access-date=20 April 2020|archive-date=13 April 2009|archive-url=https://web.archive.org/web/20090413015818/http://variety.com/article/VR1117961488.html?categoryid=1275&cs=1|url-status=live}}</ref><ref name="NatGeo Time" /> [[Drive-in theater|drive-ins]] and other theaters.<ref>{{cite book|author=Todd D. Rakoff|title=A Time for Every Purpose: Law and the Balance of Life|publisher=Harvard University Press|year=2002|isbn=978-0-674-00910-3|page=26}}</ref> Artificial outdoor lighting has a marginal and sometimes even contradictory influence on crime and fear of crime.<ref>{{cite journal |author1=Rachel Pain |author2=Robert MacFarlane |author3=Keith Turner |author4=Sally Gill |year=2006 |title='When, where, if, and but': qualifying GIS and the effect of streetlighting on crime and fear |journal=Environment and Planning A |volume=38 |issue=11 |pages=2055–2074 |doi=10.1068/a38391 |bibcode=2006EnPlA..38.2055P |s2cid=143511067}}</ref>

Later sunsets from DST are thought to affect behavior; for example, increasing participation in after-school sports programs or outdoor afternoon sports such as golf, and attendance at professional sporting events.<ref name="Downing-2018">{{Cite news|last=Downing|first=Michael|date=9 March 2018|title=One Hundred Years Later, the Madness of Daylight Saving Time Endures|work=Smithsonian|url=https://www.smithsonianmag.com/history/100-years-later-madness-daylight-saving-time-endures-180968435/|access-date=12 March 2018|quote=Today we know that changing the clocks does influence our behavior. For example, later sunset times have dramatically increased participation in afterschool sports programs and attendance at professional sports events. In 1920, The Washington Post reported that golf ball sales in 1918—the first year of daylight saving—increased by 20 percent.|archive-date=11 March 2018|archive-url=https://web.archive.org/web/20180311215048/https://www.smithsonianmag.com/history/100-years-later-madness-daylight-saving-time-endures-180968435/|url-status=live}}</ref> Advocates of daylight saving time argue that having more hours of daylight between the end of a typical workday and evening induces people to consume other goods and services.<ref>{{cite news|author=Dana Knight|date=17 April 2006|title=Daylight-saving time becomes daylight-spending time for many businesses|work=Indianapolis Star}}</ref><ref name="CBC News-2020" /><ref>{{Cite news|last=Bradley|first=Barbara|date=3 April 1987|title=For business, Daylight Saving Time is daylight spending time|work=The Christian Science Monitor}}</ref>

In 2022, a publication of three replicating studies of individuals, between individuals, and transecting societies, demonstrated that sleep loss affects the human motivation to help others, which in its [[Functional magnetic resonance imaging|fMRI]] findings is "associated with deactivation of key nodes within the social cognition brain network that facilitates prosociality." Furthermore, they detected, through analysis of over three million real-world charitable donations, that the loss of sleep inflicted by the transition to daylight saving time reduces altruistic giving compared to controls (being states not implementing DST). They conclude that the effects on civil society are "non-trivial".<ref>{{Cite journal |last1=Simon |first1=Eti Ben |last2=Vallat |first2=Raphael |last3=Rossi |first3=Aubrey |last4=Walker |first4=Matthew P. |date=23 August 2022 |title=Sleep loss leads to the withdrawal of human helping across individuals, groups, and large-scale societies |journal=PLOS Biology |language=en |volume=20 |issue=8 |pages=e3001733 |doi=10.1371/journal.pbio.3001733 |issn=1545-7885 |pmc=9398015 |pmid=35998121 |doi-access=free }}</ref>

Another study, which also examined sleep manipulation due to the shift to daylight saving time in the spring, analyzed archival data from judicial punishment imposed by US federal courts which showed sleep-deprived judges exact more severe penalties.<ref>{{Cite journal |last1=Cho |first1=Kyoungmin |last2=Barnes |first2=Christopher M. |last3=Guanara |first3=Cristiano L. |date=13 December 2016 |title=Sleepy Punishers Are Harsh Punishers |url=http://dx.doi.org/10.1177/0956797616678437 |journal=Psychological Science |volume=28 |issue=2 |pages=242–247 |doi=10.1177/0956797616678437 |pmid=28182529 |s2cid=11321574 |issn=0956-7976}}</ref>

=== Inconvenience ===
DST's clock shifts have the disadvantage of complexity. People must remember to change their clocks; this can be time-consuming, particularly for mechanical clocks that cannot be moved backward safely.<ref>{{cite news|url=http://www.recordcourier.com/apps/pbcs.dll/article?AID=/20031024/NEWS/310240104 |work=Record–Courier |date=24 October 2003 |title=Daylight saving time ends Sunday |author=Joey Crandall |url-status=dead |archive-url=https://web.archive.org/web/20120229232157/http://www.recordcourier.com/apps/pbcs.dll/article?AID=%2F20031024%2FNEWS%2F310240104 |archive-date=29 February 2012 }}</ref> People who work across time zone boundaries need to keep track of multiple DST rules, as not all locations observe DST or observe it the same way. The length of the calendar day becomes variable; it is no longer always 24 hours. Disruption to meetings, travel, broadcasts, billing systems, and records management is common, and can be expensive.<ref>{{cite news |author=Paul McDougall |title=PG&E says patching meters for an early daylight-saving time will cost $38&nbsp;million |work=InformationWeek |url=http://www.informationweek.com/news/internet/showArticle.jhtml?articleID=197700487 |date=1 March 2007 |access-date=13 February 2009 |archive-date=6 December 2008 |archive-url=https://web.archive.org/web/20081206010328/http://www.informationweek.com/news/internet/showArticle.jhtml?articleID=197700487 |url-status=live }}</ref> During an autumn transition from 02:00 to 01:00, a clock shows local times from 01:00:00 through 01:59:59 twice, possibly leading to confusion.<ref>{{cite web |url=http://www.webexhibits.org/daylightsaving/c.html |year=2008 |title=Daylight saving time: rationale and original idea |quote=...&nbsp;Lord Balfour came forward with a unique concern: 'Supposing some unfortunate lady was confined with twins&nbsp;...' |access-date=13 February 2009 |archive-date=9 June 2016 |archive-url=https://web.archive.org/web/20160609015207/http://www.webexhibits.org/daylightsaving/c.html |url-status=live }}</ref>

Many farmers oppose DST, particularly [[dairy farmers]] as the milking patterns of their cows do not change with the time,<ref name="NatGeo Time">{{cite news |author=Brian Handwerk |date=1 December 2013 |title=Time to Move On? The Case Against Daylight Saving Time |publisher=[[National Geographic News]] |url=http://news.nationalgeographic.com/news/2013/11/131101-when-does-daylight-savings-time-end-november-3-science/ |url-status=dead |access-date=9 March 2014 |archive-url=https://web.archive.org/web/20140313140334/http://news.nationalgeographic.com/news/2013/11/131101-when-does-daylight-savings-time-end-november-3-science/ |archive-date=13 March 2014}}</ref><ref name="NFU">{{cite web|title=Should we change the clocks?|url=http://www.nfuonline.com/News/Should-we-change-the-clocks-/|url-status=dead|archive-url=https://archive.today/20120314021932/http://www.nfuonline.com/News/Should-we-change-the-clocks-/|archive-date=14 March 2012|access-date=6 January 2012|publisher=National Farmers Union}}</ref><ref>{{Cite news|last=Crossen|first=Cynthia|date=6 November 2003|title=Daylight Saving Time Pitted Farmers Against The 'Idle' City Folk|language=en-US|work=[[The Wall Street Journal]]|url=https://www.wsj.com/articles/SB106798569494029700|access-date=4 December 2020|issn=0099-9660|archive-date=28 March 2021|archive-url=https://web.archive.org/web/20210328235545/https://www.wsj.com/articles/SB106798569494029700|url-status=live}}</ref> and others whose hours are set by the sun.<ref name="farming">Effect on those whose hours are set by the sun:
* {{harvp|''Spring Forward''|2005|pp=19–33}}
* {{harvp|''Seize the Daylight''|2005|pp=103–110, 149–151, 198}}</ref> There is concern for schoolchildren who are out in the darkness during the morning due to late sunrises.<ref name="NatGeo Time" />

=== Remediation ===
Some clock-shift problems could be avoided by adjusting clocks continuously<ref>{{cite web |url=http://www.squarefree.com/2006/11/01/continuous-daylight-saving-time/ |title=Continuous daylight saving time |author=Jesse Ruderman |date=1 November 2006 |access-date=21 March 2007 |archive-date=4 May 2016 |archive-url=https://web.archive.org/web/20160504080610/http://www.squarefree.com/2006/11/01/continuous-daylight-saving-time/ |url-status=live }}</ref> or at least more gradually<ref>{{cite web |url=http://jeppesn.dk/summertime.html |title=Proposal for a finer adjustment of summer time (daylight saving time) |date=28 September 2011 |access-date=28 September 2011 |archive-date=8 October 2011 |archive-url=https://web.archive.org/web/20111008213011/http://jeppesn.dk/summertime.html |url-status=live }}</ref>—for example, Willett at first suggested weekly 20-minute transitions—but this would add complexity and has never been implemented. DST inherits and can magnify the disadvantages of standard time. For example, when reading a [[sundial]], one must compensate for it along with time zone and natural discrepancies.<ref>{{cite book |title=Sundials: Their Theory and Construction |author=Albert E. Waugh |publisher=Dover |isbn=978-0-486-22947-8 |year=1973 |bibcode=1973sttc.book.....W |url=https://archive.org/details/sundialstheirthe00albe }}</ref> Also, sun-exposure guidelines such as avoiding the sun within two hours of noon become less accurate when DST is in effect.<ref>{{cite journal |journal=Photochemistry and Photobiology |year=1992 |volume=56 |issue=2 |pages=229–234 |title=Atmospheric sun protection factor on clear days: its observed dependence on solar zenith angle and its relevance to the shadow guideline for sun protection |author=Leith Holloway |doi=10.1111/j.1751-1097.1992.tb02151.x |pmid=1502267 |s2cid=1219032 |url=https://zenodo.org/record/1230779 |access-date=6 June 2020 |archive-date=9 August 2020 |archive-url=https://web.archive.org/web/20200809031254/https://zenodo.org/record/1230779 |url-status=live }}</ref>