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 exposure | Reference |
---|---|---|---|---|---|---|
All causes | England and Wales | 2012 | 499,331 | 56,567,000 | 24 per day 8,800 per year |
ONS Deaths[4] Table 5. |
Canada | 2011 | 242,074 | 33,476,688 | 20 per day 7,200 per year |
Statistics Canada[5] | |
US | 2010 | 2,468,435 | 308,500,000 | 22 per day 8,000 per year |
CDC Deaths[6] Table 18. | |
Non-natural cause | England and Wales | 2012 | 17,462 | 56,567,000 | 0.8 per day 300 per year |
ONS Deaths[4] Table 5.19. |
US | 2010 | 180,000 | 308,500,000 | 1.6 per day 580 per year |
CDC Deaths[6] Table 18 | |
Non-natural cause (excluding suicide) | England and Wales | 2012 | 12,955 | 56,567,000 | 0.6 per day 230 per year |
ONS Suicides[7] |
US | 2010 | 142,000 | 308,500,000 | 1.3 per day 460 per year |
CDC Deaths[6] Table 18. | |
All causes – first day of life | England and Wales | 2007 | 430 per first day of life | Walker, 2014[8] | ||
US | 2013 | 16.7 per day 6100 per year |
CDC Life Tables[9] Blastland & Spiegelhalter, 2014[10] | |||
Murder/homicide | England and Wales | 2012/13 | 551 | 56,567,000 | 10 per year | ONS Crime[11] |
Homicide | Canada | 2011 | 527 | 33,476,688 | 15 per year | Statistics Canada[12] |
Murder and non-negligent manslaughter | US | 2012 | 14,173 | 292,000,000 | 48 per year | FBI[13] Table 16 |
Leisure and sport
Death from | Context | Time period | N deaths | N exposure | Micromorts per unit of exposure | Reference |
---|---|---|---|---|---|---|
Scuba diving | UK: BSAC members | 1998–2009 | 75 | 14,000,000 dives | 5 per dive | BSAC[14] |
UK: non-BSAC | 1998–2009 | 122 | 12,000,000 dives | 10 per dive | BSAC[14] | |
US – insured members of DAN | 2000–2006 | 187 | 1,131,367 members | 164 per year as member of DAN 5 per dive |
DAN[15] p75 | |
Paragliding | Turkey | 2004–2011 | 18 | 242,355 flights | 74 per launch | Canbek 2015[16] |
Skiing | US | 2008/9 | 39 | 57,000,000 days skiing | 0.7 per day | Ski-injury.com[17][unreliable source] |
Skydiving | US | 2000–2016 | 413 | 48,600,000 jumps | 8 per jump | USPA[18] |
UK | 1994–2013 | 41 | 4,864,268 jumps | 8 per jump | BPA[19] | |
BASE jumping | Kjerag Massif, Norway | 1995–2005 | 9 | 20,850 jumps | 430 per jump | Soreide 2007[20] |
Mountaineering | Ascent to Matterhorn | 1981–2011 | 213 | about 75,000 ascents
(about 2500 per year) |
about 2,840 per ascent attempt | Bachmann 2012[21] |
Ascent to Mt. Everest | 1922–2012 | 223 | 5,656 successful ascents | 37,932 per successful ascent | NASA 2013[22] |
Travel
Activities that increase the death risk by roughly one micromort, and their associated cause of death:
- Travelling 6 miles (9.7 km) by motorcycle (collision)[23]
- Travelling 17 miles (27 km) by walking (collision)[23]
- Travelling 10 miles (16 km)[24] or 20 miles (32 km)[23] by bicycle (collision)[a]
- Travelling 230 miles (370 km) by car (collision) (or 250 miles)[23]
- Travelling 1,000 miles (1,600 km) by jet airplane (collision)[24]
- Travelling 6,000 miles (10,000 km) by train (collision)[26]
Other
Increase in death risk for other activities on a per-event basis:
- Hang gliding – 8 micromorts per flight[23]
- Ecstasy (MDMA) – 0.5 micromorts per tablet, rising to 13 if using other drugs[27][28]
- Giving birth (vaginal) – 120 micromorts[29]
- Giving birth (caesarean) – 170 micromorts[29]
- AstraZeneca vaccination against COVID-19 – 2.9 micromorts[30]
- COVID-19 infection at age 10 – 20 micromorts
- COVID-19 infection at age 25 – 100 micromorts
- COVID-19 infection at age 55 – 4,000 micromorts
- COVID-19 infection at age 65 – 14,000 micromorts
- COVID-19 infection at age 75 – 46,000 micromorts
- COVID-19 infection at age 85 – 150,000 micromorts (As of December 2020)[31]
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).[32][33] 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.[33]
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 £2 million in 2023[34]).[35] 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.[36]
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,[24] for example, an additional one micromort from:
- Drinking 0.5 liter of wine (cirrhosis of the liver)[24]
- Smoking 1.4 cigarettes (cancer, heart disease)[24]
- Spending 1 hour in a coal mine (black lung disease)[24]
- Spending 3 hours in a coal mine (accident)[24]
- Living 2 days in New York or Boston in 1979 (air pollution)[24]
- Living 2 months with a smoker (cancer, heart disease)[24]
- Drinking Miami water for 1 year (cancer from chloroform)[24]
- Eating 100 charcoal-broiled steaks (cancer from benzopyrene)[24]
- Traveling 6000 miles (10,000 km) by jet (cancer due to increased background radiation)[37]
Such risks are better expressed using the related concept of a microlife.
See also
- Decision analysis – Discipline covering formal decision making
- Decision theory – Branch of applied probability theory
- Ellsberg paradox – Paradox in decision theory
- List of unusual units of measurement – Units of measurement that are not part of a coherent system
- Microlife – Unit of risk – half an hour of life expectancy
- Pascal's Wager – Argument that posits human beings bet with their lives that God either exists or does not
- Precautionary principle – Risk management strategy
- Risk of ruin – Concept in gambling, insurance, and finance
Notes
- ^ however due to the health effects of cycling the net effect of cycling on life expectancy is likely positive in most cases[25]
References
- ^ Fry, A.M.; Harrison, A.; Daigneault, M. (February 2016). "Micromorts - what is the risk?". British Journal of Oral and Maxillofacial Surgery. 54 (2): 230–231. doi:10.1016/j.bjoms.2015.11.023. PMID 26747014.
- ^ Walker, KF; Cohen, AL; Walker, SS; Allen, KM; Baines, DL; Thornton, Jg (May 2014). "The dangers of the day of birth". BJOG. 121 (6): 714–718. doi:10.1111/1471-0528.12544. PMID 24521517. S2CID 24808758.
- ^ Howard, R. A. (1980). J. Richard; C. Schwing; Walter A. Albers (eds.). On making life and death decisions. Societal Risk Assessment: How Safe Is Safe Enough? General Motors Research Laboratories. New York: Plenum Press. ISBN 0306405547.
- ^ a b "Deaths Registered in England and Wales (Series DR), 2012" (PDF). Office for National Statistics. 22 October 2013. Archived (PDF) from the original on 6 June 2014. Retrieved 3 June 2014.
- ^ "Leading causes of death, by sex (Both sexes)". Statistics Canada. Archived from the original on 24 September 2015. Retrieved 14 August 2015.
- ^ a b c SL Murphy; J Xu & KD Kochanek (8 May 2013). "Deaths: Final Data for 2010" (PDF). US: Centers for Disease Control and Prevention. Archived (PDF) from the original on 11 May 2015. Retrieved 3 June 2014.
- ^ "Suicides in the United Kingdom, 2012 Registrations". Office for National Statistics. 18 February 2014. Archived from the original on 13 May 2014. Retrieved 11 June 2014.
- ^ KF Walker; AL Cohen; SH Walker; KM Allen; DL Baines; JG Thornton (13 February 2014). "The dangers of the day of birth". British Journal of Obstetrics and Gynaecology. 121 (6). London: Royal College of Obstetricians and Gynaecologists: 714–8. doi:10.1111/1471-0528.12544. PMID 24521517. S2CID 24808758.
- ^ "Life Tables". cdc.gov. Centers for Disease Control and Prevention. 2013. Archived from the original on 26 November 2013. Retrieved 24 November 2013.
- ^ Blastland, Michael; Spiegelhalter, David (2014). The Norm Chronicles: Stories and Numbers About Danger and Death (1 ed.). Basic Books. p. 14. ISBN 9780465085705.
- ^ "Crime Statistics, Focus on Violent Crime and Sexual Offences, 2012/13 – ONS". Office for National Statistics. 13 February 2014. Archived from the original on 8 April 2014. Retrieved 12 June 2014.
- ^ "Leading causes of death, total population, by age group and sex, Canada". Statistics Canada. 26 November 2020. Archived from the original on 3 July 2013. Retrieved 14 August 2015.
- ^ "Crime in the United States, 2012: Table 16". FBI. Federal Bureau of Investigation. Archived from the original on 29 May 2016. Retrieved 12 June 2014.
- ^ a b British Sub-Aqua Club. "UK Diving Fatalities Review". Archived from the original on 28 July 2014. Retrieved 12 June 2014.
- ^ Divers Alert Network (DAN). "Fatalities_Proceedings.pdf" (PDF). Archived (PDF) from the original on 16 January 2015. Retrieved 12 June 2014.
- ^ Canbek, Umut; Ahmet İmerci; Ulaş Akgün; Murat Yeşil; Ali Aydin; Yasemin Balci (1 September 2015). "Characteristics of injuries caused by paragliding accidents: A cross-sectional study". World Journal of Emergency Medicine. 6 (3): 221–224. doi:10.5847/wjem.j.1920-8642.2015.03.011. PMC 4566014. PMID 26401185.
- ^ Ski-injury.com. "Ski Injury". Archived from the original on 28 May 2014. Retrieved 12 June 2014.
- ^ United States Parachute Association. "Skydiving Safety". Archived from the original on 22 August 2018. Retrieved 10 April 2018.
- ^ British Parachute Association (2012). "How Safe". Archived from the original on 27 July 2014. Retrieved 12 June 2014.
- ^ Soreide, Kjetil; Ellingsen, Christian Lycke; Knutson, Vibeke (May 2007). "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. 62 (5): 1113–1117. doi:10.1097/01.ta.0000239815.73858.88. PMID 17495709.
- ^ Bachmann, Stefan (September 2012). "Tod am Matterhorn" (PDF). Beobachter (in German).
- ^ "The World's Tallest Mountain". Earth Observatory. NASA. 2 January 2014. Archived from the original on 25 October 2014. Retrieved 25 October 2014.
- ^ a b c d e "Understanding Uncertainty". Plus Magazine. 12 July 2010. Archived from the original on 4 August 2020. Retrieved 22 July 2020.
- ^ a b c d e f g h i j k * Howard, Ron Risky Decisions (Slide show), Stanford University
- ^ de Hartog, Jeroen Johan; Boogaard, Hanna; Nijland, Hans; Hoek, Gerard (August 2010). "Do the Health Benefits of Cycling Outweigh the Risks?". Environmental Health Perspectives. 118 (8): 1109–1116. doi:10.1289/ehp.0901747. PMC 2920084. PMID 20587380.
- ^ Safety Overview 2023 (PDF) (Report). European Union Agency For Railways. March 2023. p. 7, fig. 6.
- ^ "MDMA ('ecstasy'): a review of its harms and classification under the Misuse of Drugs Act 1971". London: Advisory Council on the Misuse of Drugs. 2009. p. 18. Archived from the original on 5 October 2012 – via Internet Archive.
- ^ Blastland, Michael; Spiegelhalter, David (2014). The Norm Chronicles: Stories and Numbers About Danger and Death (1 ed.). Basic Books. p. 8. ISBN 9780465085705.
- ^ a b Spiegelhalter, David; Blastland, Michael (30 May 2013). The Norm Chronicles: Stories and numbers about danger (Main ed.). London: Profile Books. ISBN 9781846686207.
- ^ Nina Weber, DER SPIEGEL (22 April 2021). "Coronaimpfung und Risikoabwägung: Einmal impfen ist weniger riskant als eine Woche Skiurlaub". Der Spiegel (in German). Archived from the original on 18 February 2022. Retrieved 11 June 2021.
- ^ Levin AT, Hanage WP, Owusu-Boaitey N, Cochran KB, Walsh SP, Meyerowitz-Katz G (December 2020). "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. doi:10.1007/s10654-020-00698-1. PMC 7721859. PMID 33289900.
Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License Archived 16 October 2017 at the Wayback Machine.
- ^ Howard, R. A. (1989). "Microrisks for Medical Decision Analysis". International Journal of Technology Assessment in Health Care. 5 (3): 357–370. doi:10.1017/S026646230000742X. PMID 10295520. S2CID 37558060.
- ^ a b Russell, Stuart; Norvig, Peter (2009). Artificial Intelligence (3rd ed.). Prentice Hall. p. 616. ISBN 978-0-13-604259-4.
- ^ UK Retail Price Index inflation figures are based on data from Clark, Gregory (2017). "The Annual RPI and Average Earnings for Britain, 1209 to Present (New Series)". MeasuringWorth. Retrieved 7 May 2024.
- ^ "Unit A4.1: Social Impact Appraisal" (PDF). Transport analysis guidance. London: Department for Transport. January 2014. p. 6.
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ignored (help) - ^ 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 Archived 2 November 2014 at the Wayback Machine
- ^ "Radiation dose issues and risk" (PDF). European Society of Radiology. Archived from the original (PDF) on 19 February 2014. Retrieved 18 November 2013.
Further reading
- Ronald A. Howard (1984). "On Fates Comparable to Death". Management Science. 30 (4): 407–422. doi:10.1287/mnsc.30.4.407.
- Center for the Study & Improvement of Regulation. "What is a MicroMort?". Archived from the original on 15 April 2013.[unreliable source?]