Micromort Explained

A micromort (from micro- and mortality) is a unit of risk defined as a one-in-a-million chance of death.[1] [2] Micromorts can be used to measure the riskiness of various day-to-day activities. A microprobability is a one-in-a million chance of some event; thus, a micromort is the microprobability of death. The micromort concept was introduced by Ronald A. Howard who pioneered the modern practice of decision analysis.[3]

Micromorts for future activities can only be rough assessments, as specific circumstances will always have an impact. However, past historical rates of events can be used to provide a rough estimate.

Sample values

Baseline

Death from Context Time period N deaths N population Micromorts per unit of exposureReference
All causesEngland and Wales2012499,33156,567,00024 per day
8,800 per year
ONS Deaths[4] Table 5.
Canada2011242,07433,476,68820 per day
7,200 per year
Statistics Canada[5]
US20102,468,435308,500,00022 per day
8,000 per year
CDC Deaths[6] Table 18.
Non-natural causeEngland and Wales201217,46256,567,0000.8 per day
300 per year
ONS Deaths Table 5.19.
US2010180,000308,500,0001.6 per day
580 per year
CDC Deaths Table 18
Non-natural cause (excluding suicide)England and Wales201212,95556,567,0000.6 per day
230 per year
ONS Suicides[7]
US2010142,000308,500,0001.3 per day
460 per year
CDC Deaths Table 18.
All causes – first day of lifeEngland and Wales2007430 per first day of lifeWalker, 2014[8]
US201316.7 per day
6100 per year
CDC Life Tables[9]
Blastland & Spiegelhalter, 2014[10]
Murder/homicideEngland and Wales2012/1355156,567,00010 per yearONS Crime[11]
HomicideCanada201152733,476,68815 per yearStatistics Canada[12]
Murder and non-negligent manslaughterUS201214,173292,000,00048 per yearFBI[13] Table 16

Leisure and sport

Death from Context Time period N deaths N exposure Micromorts per unit of exposure Reference
Scuba divingUK: BSAC members1998–20097514,000,000 dives5 per diveBSAC[14]
UK: non-BSAC1998–200912212,000,000 dives10 per diveBSAC
US – insured members of DAN2000–20061871,131,367 members164 per year as member of DAN
5 per dive
DAN[15] p75
ParaglidingTurkey2004–201118242,355 flights74 per launchCanbek 2015[16]
SkiingUS2008/93957,000,000 days skiing0.7 per daySki-injury.com[17]
SkydivingUS2000–201641348,600,000 jumps8 per jumpUSPA[18]
UK1994–2013414,864,268 jumps8 per jumpBPA[19]
BASE jumpingKjerag Massif, Norway1995–2005920,850 jumps430 per jumpSoreide 2007[20]
MountaineeringAscent to Matterhorn1981–2011213about 75,000 ascents(about 2500 per year)about 2,840 per ascent attemptBachmann 2012[21]
Ascent to Mt. Everest1922–20122235,656 successful ascents37,932 per successful ascentNASA 2013[22]

Travel

Activities that increase the death risk by roughly one micromort, and their associated cause of death:

Other

Increase in death risk for other activities on a per-event basis:

Value of a micromort

Willingness to pay

An application of micromorts is measuring the value that humans place on risk. For example, a person can consider the amount of money they would be willing to pay to avoid a one-in-a-million chance of death (or conversely, the amount of money they would receive to accept a one-in-a-million chance of death). When offered this situation, people claim a high number. However, when looking at their day-to-day actions (e.g., how much they are willing to pay for safety features on cars), a typical value for a micromort is around $50 (in 2009).[30] [31] This is not to say the $50 valuation should be taken to mean that a human life (1 million micromorts) is valued at $50,000,000. Rather, people are less inclined to spend money after a certain point to increase their safety. This means that analyzing risk using the micromort is more useful when using small risks, not necessarily large ones.[31]

Value of a statistical life

Government agencies use a nominal Value of a Statistical Life (VSL) – or Value for Preventing a Fatality (VPF) – to evaluate the cost-effectiveness of expenditure on safeguards. For example, in the UK, the VSL is £1 million GBP in 1997 value (equivalent to £ million in).[32] Since road improvements have the effect of lowering the risk of large numbers of people by a small amount, the UK Department for Transport essentially prices a reduction of 1 micromort at £1.60. The US Department of Transportation uses a VSL of US$6.2 million, pricing a micromort at US$6.20.[33]

Chronic risks

Micromorts are best used to measure the size of acute risks, i.e. immediate deaths. Risks from lifestyle, exposure to air pollution, and so on are chronic risks, in that they do not kill straight away, but reduce life expectancy. Ron Howard included such risks in his original 1979 work, for example, an additional one micromort from:

Such risks are better expressed using the related concept of a microlife.

Further reading

External links

Notes and References

  1. Fry . A.M. . Harrison . A. . Daigneault . M. . Micromorts - what is the risk? . British Journal of Oral and Maxillofacial Surgery . February 2016 . 54 . 2 . 230–231 . 10.1016/j.bjoms.2015.11.023 . 26747014 .
  2. Walker . KF . Cohen . AL . Walker . SS . Allen . KM . Baines . DL . Thornton . Jg . The dangers of the day of birth . BJOG . May 2014 . 121 . 6 . 714–718 . 10.1111/1471-0528.12544 . 24521517 . 24808758 .
  3. Howard . R. A. . Ronald A. Howard . On making life and death decisions . J. Richard . C. Schwing . Walter A. Albers . Societal Risk Assessment: How Safe Is Safe Enough? General Motors Research Laboratories . Plenum Press . New York . 0306405547 . 1980.
  4. Web site: Deaths Registered in England and Wales (Series DR), 2012 . Office for National Statistics . 2013-10-22 . 2014-06-03 . 6 June 2014 . https://web.archive.org/web/20140606215559/http://www.ons.gov.uk/ons/dcp171778_331565.pdf . live .
  5. Web site: Leading causes of death, by sex (Both sexes). Statistics Canada. 14 August 2015. 24 September 2015. https://web.archive.org/web/20150924130923/http://www.statcan.gc.ca/tables-tableaux/sum-som/l01/cst01/hlth36a-eng.htm. live.
  6. Web site: Deaths: Final Data for 2010 . US . SL Murphy . J Xu . KD Kochanek . amp . . 2013-05-08 . 2014-06-03 . 11 May 2015 . https://web.archive.org/web/20150511223214/http://www.cdc.gov/nchs/data/nvsr/nvsr61/nvsr61_04.pdf . live .
  7. Web site: Suicides in the United Kingdom, 2012 Registrations . Office for National Statistics . 2014-02-18 . 2014-06-11 . 13 May 2014 . https://web.archive.org/web/20140513052104/http://www.ons.gov.uk/ons/rel/subnational-health4/suicides-in-the-united-kingdom/2012/stb-uk-suicides-2012.html#tab-Suicides-in-England-and-Wales . live .
  8. The dangers of the day of birth . KF Walker . AL Cohen . SH Walker . KM Allen . DL Baines . JG Thornton . . British Journal of Obstetrics and Gynaecology . 2014-02-13 . 10.1111/1471-0528.12544 . 24521517 . 121 . 6 . 714–8. 24808758 . London.
  9. Web site: Life Tables. cdc.gov. Centers for Disease Control and Prevention. 24 November 2013. 2013. 26 November 2013. https://web.archive.org/web/20131126224714/http://www.cdc.gov/nchs/products/life_tables.htm. live.
  10. Book: Blastland. Michael. Spiegelhalter. David. The Norm Chronicles: Stories and Numbers About Danger and Death. 2014. Basic Books. 9780465085705. 14. 1.
  11. Web site: Office for National Statistics. Crime Statistics, Focus on Violent Crime and Sexual Offences, 2012/13 – ONS. 2014-06-12. 2014-02-13. 8 April 2014. https://web.archive.org/web/20140408220732/http://www.ons.gov.uk/ons/rel/crime-stats/crime-statistics/focus-on-violent-crime-and-sexual-offences--2012-13/index.html. live.
  12. Web site: Leading causes of death, total population, by age group and sex, Canada. Statistics Canada. 26 November 2020. 14 August 2015. 3 July 2013. https://web.archive.org/web/20130703044031/http://www5.statcan.gc.ca/cansim/a26?lang=eng&retrLang=eng&id=1020561&paSer=&pattern=&stByVal=1&p1=1&p2=37&tabMode=dataTable&csid=. live.
  13. Web site: Federal Bureau of Investigation. Crime in the United States, 2012: Table 16. FBI. 2014-06-12. 29 May 2016. https://web.archive.org/web/20160529074718/https://www.fbi.gov/about-us/cjis/ucr/crime-in-the-u.s/2012/crime-in-the-u.s.-2012/tables/16tabledatadecpdf/table_16_rate_by_population_group_2012.xls/. live.
  14. Web site: British Sub-Aqua Club . UK Diving Fatalities Review . 2014-06-12 . dead . https://web.archive.org/web/20140728111842/http://www.bsac.com/page.asp?section=3780&sectionTitle=UK+Diving+Fatalities+Review . 28 July 2014.
  15. Web site: Divers Alert Network (DAN). Fatalities_Proceedings.pdf. 2014-06-12. 16 January 2015. https://web.archive.org/web/20150116220829/http://www.diversalertnetwork.org/files/Fatalities_Proceedings.pdf. live.
  16. 10.5847/wjem.j.1920-8642.2015.03.011. 26401185. 6. 3. 221–224. Canbek. Umut. Ahmet İmerci. Ulaş Akgün. Murat Yeşil. Ali Aydin. Yasemin Balci . Characteristics of injuries caused by paragliding accidents: A cross-sectional study . World Journal of Emergency Medicine . 2015-09-01. 4566014.
  17. Web site: Ski-injury.com . Ski Injury . 2014-06-12 . dead . https://web.archive.org/web/20140528075539/http://www.ski-injury.com/intro . 28 May 2014.
  18. Web site: United States Parachute Association. Skydiving Safety. 2018-04-10. 22 August 2018. https://web.archive.org/web/20180822014822/https://uspa.org/Find/FAQs/Safety. live.
  19. Web site: British Parachute Association. How Safe. 2014-06-12. 2012. https://web.archive.org/web/20140727093743/http://www.bpa.org.uk/staysafe/how-safe/. 27 July 2014. dead.
  20. Soreide . Kjetil . Ellingsen . Christian Lycke . Knutson . Vibeke . How Dangerous is BASE Jumping? An Analysis of Adverse Events in 20,850 Jumps From the Kjerag Massif, Norway . The Journal of Trauma: Injury, Infection, and Critical Care . May 2007 . 62 . 5 . 1113–1117 . 10.1097/01.ta.0000239815.73858.88 . 17495709 .
  21. Tod am Matterhorn. Beobachter. de. Bachmann. Stefan. September 2012.
  22. Web site: The World's Tallest Mountain. 2 January 2014. Earth Observatory. NASA. 25 October 2014. 25 October 2014. https://web.archive.org/web/20141025063724/http://earthobservatory.nasa.gov/IOTD/view.php?id=82578. live.
  23. Web site: Understanding Uncertainty. 12 July 2010. Plus Magazine. 22 July 2020. 4 August 2020. https://web.archive.org/web/20200804110023/https://plus.maths.org/content/os/issue55/features/risk/index. live.
  24. March 2023 . Safety Overview 2023 . European Union Agency For Railways . p. 7, fig. 6 .
  25. Web site: . MDMA ('ecstasy'): a review of its harms and classification under the Misuse of Drugs Act 1971 . London. 2009 . 18 . https://web.archive.org/web/20121005073938/http://www.homeoffice.gov.uk/publications/agencies-public-bodies/acmd1/mdma-report . 5 October 2012 . Internet Archive.
  26. Book: Blastland. Michael. Spiegelhalter. David. The Norm Chronicles: Stories and Numbers About Danger and Death. 2014. Basic Books. 9780465085705. 8. 1.
  27. Book: The Norm Chronicles: Stories and numbers about danger. Spiegelhalter. David. Blastland. Michael. 2013-05-30. Profile Books. 9781846686207. Main . London. en.
  28. News: Coronaimpfung und Risikoabwägung: Einmal impfen ist weniger riskant als eine Woche Skiurlaub. live. 2021-06-11. https://web.archive.org/web/20220218102607/https://www.spiegel.de/gesundheit/diagnose/corona-impfung-und-risikoabwaegung-einmal-impfen-ist-weniger-riskant-als-eine-woche-skiurlaub-a-6438059e-06e0-4340-add3-cc9b07a5f501. 18 February 2022. Nina Weber, DER SPIEGEL. Der Spiegel. 22 April 2021. de.
  29. Levin AT, Hanage WP, Owusu-Boaitey N, Cochran KB, Walsh SP, Meyerowitz-Katz G . Assessing the age specificity of infection fatality rates for COVID-19: systematic review, meta-analysis, and public policy implications . European Journal of Epidemiology . 35 . 12 . 1123–1138 . December 2020 . 33289900 . 7721859 . 10.1007/s10654-020-00698-1 . free . Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License .
  30. Howard . R. A. . Ronald A. Howard. Microrisks for Medical Decision Analysis. International Journal of Technology Assessment in Health Care. 5. 1989. 357–370. 10295520. 10.1017/S026646230000742X. 3. 37558060 .
  31. Book: Russell . Stuart. Norvig . Peter. Artificial Intelligence. 3rd. 978-0-13-604259-4. Prentice Hall. 2009. 616.
  32. Book: . Transport analysis guidance . Unit A4.1: Social Impact Appraisal . January 2014 . London . . https://assets.publishing.service.gov.uk/media/63a32a8d8fa8f539198d9bf3/TAG_Unit_A4.1_-_Social-impact-appraisal_Nov_2022_Accessible_v1.0.pdf.pdf . 6 .
  33. US Department of Transportation, "Treatment of the Economic Value of a Statistical Life in Departmental Analyses—2011 Interim Adjustment", 2011, http://www.dot.gov/policy/transportation-policy/treatment-economic-value-statistical-life
  34. Web site: Radiation dose issues and risk. European Society of Radiology. 2013-11-18. dead. https://web.archive.org/web/20140219020315/http://www.myesr.org/html/img/pool/15_Loose_Reinhard_Radiation_Dose_Issues_and_Risk.pdf. 19 February 2014.