A micromort (from micro- and mortality) is a unit of risk defined as one-in-a-million chance of death. Micromorts can be used to measure 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.
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 ball-park, average figure.
|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 Table 5.|
|All causes||Canada||2011||242,074||33,476,688||20 per day
7,200 per year
|All causes||US||2010||2,468,435||308,500,000||22 per day
8,000 per year
|CDC Deaths Table 18.|
|Non-natural cause||England and Wales||2012||17,462||56,567,000||0.8 per day
300 per year
|ONS Deaths Table 5.19.|
|Non-natural cause||US||2010||180,000||308,500,000||1.6 per day
580 per year
|CDC Deaths Table 18|
|Non-natural cause (excluding suicide)||England and Wales||2012||12,955||56,567,000||0.6 per day
230 per year
|Non-natural cause (excluding suicide)||US||2010||142,000||308,500,000||1.3 per day
460 per year
|CDC Deaths Table 18.|
|All causes – first day of life||England and Wales||2007||430 per first day of life||Walker, 2014|
|All causes - first year of life||US||2013||16.7 per day
6100 per year
|CDC Life Tables |
Blastland & Spiegelhalter, 2014
|Murder/homicide||England and Wales||2012/13||551||56,567,000||10 per year||ONS Crime|
|Homicide||Canada||2011||527||33,476,688||15 per year||Statistics Canada|
|Murder and non-negligent manslaughter||US||2012||14,173||292,000,000||48 per year||FBI Table 16|
|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|
|Scuba diving||UK: non-BSAC||1998–2009||122||12,000,000 dives||10 per dive||BSAC|
|Scuba diving||US – insured members of DAN||2000–2006||187||1,131,367 members||164 per year as member of DAN
5 per dive
|Skiing||US||2008/9||39||57,000,000 days skiing||0.7 per day||Ski-injury.com|
|Skydiving||US||2000–2016||413||48,600,000 jumps||8 per jump||USPA|
|Skydiving||UK||1994–2013||41||4,864,268 jumps||8 per jump||BPA|
|Running marathon||US||1975–2004||26||3,300,000 runs||7 per run||Kipps C 2011|
|Base-jumping||Kjerag Massif, Norway||1995–2005||9||20,850 jumps||430 per jump||Soreide 2007|
|Mountaineering||Ascent to Matterhorn||1981–2011||213||about 75,000 ascents
(about 2500 per year)
|about 2840 per ascent attempt||Bachmann 2012|
|Mountaineering||Ascent to Mt. Everest||1922–2012||223||5,656 successful ascents||37,932 per ascent attempt||NASA 2013|
Activities that increase the death risk by roughly one micromort, and their associated cause of death:
Increase in death risk for other activities on a per event basis:
An application of micromorts is measuring the value that humans place on risk: for example, one can consider the amount of money one would have to pay a person to get him or her to accept a one-in-a-million chance of death (or conversely the amount that someone might be willing to pay to avoid a one-in-a-million chance of death). When put thus, people claim a high number but when inferred from their day-to-day actions (e.g., how much they are willing to pay for safety features on cars) a typical value is around $50 (in 2009). However utility functions are often not linear, i.e. the more a person has already spent on their safety the less they are willing to spend to further increase their safety. Therefore, the $50 valuation should not be taken to mean that a human life (1 million micromorts) is valued at $50,000,000. Furthermore, the local linearity of any utility curve means that the micromort is useful for small incremental risks and rewards, not necessarily for large risks.
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 stands at £1.6 million for road improvements. 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 (US$2.70). The US Department of Transportation uses a VSL of US$6.2 million, pricing a Micromort at US$6.20.
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.
Algor mortis (Latin: algor—coldness; mortis—of death), the second stage of death, is the change in body temperature post mortem, until the ambient temperature is matched. This is generally a steady decline, although if the ambient temperature is above the body temperature (such as in a hot desert), the change in temperature will be positive, as the (relatively) cooler body acclimates to the warmer environment. External factors can have a significant influence.
The term was first used by Dowler in 1849. The first published measurements of the intervals of temperature after death were done by Dr John Davey in 1839.Dead on arrival
Dead on arrival (DOA), also dead in the field and brought in dead (BID), indicates that a patient was found to be already clinically dead upon the arrival of professional medical assistance, often in the form of first responders such as emergency medical technicians, paramedics, or police.
In some jurisdictions, first responders must consult verbally with a physician before officially pronouncing a patient deceased, but once cardiopulmonary resuscitation is initiated, it must be continued until a physician can pronounce the patient dead.Death messenger
Death messengers, in former times, were those who were dispatched to spread the news that an inhabitant of their city or village had died. They were to wear unadorned black and go door to door with the message, "You are asked to attend the funeral of the departed __________ at (time, date, and place)." This was all they were allowed to say, and were to move on to the next house immediately after uttering the announcement. This tradition persisted in some areas to as late as the mid-19th century.Death rattle
Terminal respiratory secretions (or simply terminal secretions), known colloquially as a death rattle, are sounds often produced by someone who is near death as a result of fluids such as saliva and bronchial secretions accumulating in the throat and upper chest. Those who are dying may lose their ability to swallow and may have increased production of bronchial secretions, resulting in such an accumulation. Usually, two or three days earlier, the symptoms of approaching death can be observed as saliva accumulates in the throat, making it very difficult to take even a spoonful of water. Related symptoms can include shortness of breath and rapid chest movement. While death rattle is a strong indication that someone is near death, it can also be produced by other problems that cause interference with the swallowing reflex, such as brain injuries.It is sometimes misinterpreted as the sound of the person choking to death, or alternatively, that they are gargling.Dignified death
Dignified death is a somewhat elusive concept often related to suicide. One factor that has been cited as a core component of dignified death is maintaining a sense of control. Another view is that a truly dignified death is an extension of a dignified life. There is some concern that assisted suicide does not guarantee a dignified death, since some patients may experience complications such as nausea and vomiting. There is some concern that age discrimination denies the elderly a dignified death.Fan death
Fan death is a well-known superstition in Korean culture, where it is thought that running an electric fan in a closed room with unopened or no windows will prove fatal. Despite no concrete evidence to support the concept, belief in fan death persists to this day in Korea, and also to a lesser extent in Japan.Lazarus sign
The Lazarus sign or Lazarus reflex is a reflex movement in brain-dead or brainstem failure patients, which causes them to briefly raise their arms and drop them crossed on their chests (in a position similar to some Egyptian mummies). The phenomenon is named after the Biblical figure Lazarus of Bethany, whom Jesus Christ raised from the dead in the Gospel of John.List of unusual units of measurement
An unusual unit of measurement is a unit of measurement that does not form part of a coherent system of measurement; especially in that its exact quantity may not be well known or that it may be an inconvenient multiple or fraction of base units in such systems.
This definition is not exact since it includes units such as the week or the light-year are quite "usual" in the sense that they are often used but which can be "unusual" if taken out of their common context, as demonstrated by the Furlong/Firkin/Fortnight (FFF) system of units.
Many of the unusual units of measurements listed here are colloquial measurements, units devised to compare a measurement to common and familiar objects.Megadeath
Megadeath (or megacorpse) is one million human deaths, usually caused by a nuclear explosion. The term was used by scientists and thinkers who strategized likely outcomes of all-out nuclear warfare.Microlife
A microlife is a unit of risk representing half an hour change of life expectancy.Introduced by David Spiegelhalter and Alejandro Leiva, microlives are intended as a simple way of communicating the impact of a lifestyle or environmental risk factor, based on the associated daily proportional effect on expected length of life. Similar to the micromort (one in a million probability of death) the microlife is intended for "rough but fair comparisons between the sizes of chronic risks". This is to avoid the biasing effects of describing risks in relative hazard ratios, converting them into somewhat tangible units. Similarly they bring long-term future risks into the here-and-now as a gain or loss of time.
"A daily loss or gain of 30 minutes can be termed a microlife, because 1 000 000 half hours (57 years) roughly corresponds to a lifetime of adult exposure."The microlife exploits that for small hazard ratios the change in life expectancy is roughly linear. They are by necessity rough estimates, based on averages over population and lifetime. Effects of individual variability, short-term or changing habits, and causal factors are not taken into account.Micromort (software)
MICROMORT is a computer program (by Heisey and Fuller, 1985) used to estimate mortality rates, commonly used in ecological studies.Mortality rate
Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular population, scaled to the size of that population, per unit of time. Mortality rate is typically expressed in units of deaths per 1,000 individuals per year; thus, a mortality rate of 9.5 (out of 1,000) in a population of 1,000 would mean 9.5 deaths per year in that entire population, or 0.95% out of the total. It is distinct from "morbidity", which is either the prevalence or incidence of a disease, and also from the incidence rate (the number of newly appearing cases of the disease per unit of time).
In the generic form, mortality rates are calculated as:
where d represents the deaths occurring within a given time period, p represents the size of the population in which the deaths occur and is a conversion factor from fraction to some other unit (such as multiplying by to get mortality rate per 1,000 individuals).Necronym
A necronym (from the Greek words νεκρός, nekros, "dead" and ὄνομα ónoma, "name") is a reference to, or name of, a person who has died. Many cultures have taboos and traditions associated with referring to such a person. These vary from the extreme of never again speaking the person's real name, often using some circumlocution instead, to the opposite extreme of commemorating it incessantly by naming other things or people after the deceased.
For instance, in some cultures it is common for a newborn child to receive the name (a necronym) of a relative who has recently died, while in others to reuse such a name would be considered extremely inappropriate or even forbidden. While this varies from culture to culture, the use of necronyms is quite common.Necrophobia
Necrophobia is a specific phobia which is the irrational fear of dead things (e.g., corpses) as well as things associated with death (e.g., coffins, tombstones, funerals, cemeteries). With all types of emotions, obsession with death becomes evident in both fascination and objectification. In a cultural sense, necrophobia may also be used to mean a fear of the dead by a cultural group, e.g., a belief that the spirits of the dead will return to haunt the living.Symptoms include: shortness of breath, rapid breathing, irregular heartbeat, sweating, dry mouth and shaking, feeling sick and uneasy, psychological instability, and an altogether feeling of dread and trepidation. The sufferer may feel this phobia all the time. The sufferer may also experience this sensation when something triggers the fear, like a close encounter with a dead animal or the funeral of a loved one or friend. The fear may have developed when a person witnessed a death, or was forced to attend a funeral as a child. Some people experience this after viewing frightening media.The fear can manifest itself as a serious condition. Treatment options include medication and therapy.The word necrophobia is derived from the Greek nekros (νεκρός) for "corpse" and the Greek phobos (φόβος) for "fear".Obituary
An obituary (obit for short) is a news article that reports the recent death of a person, typically along with an account of the person's life and information about the upcoming funeral. In large cities and larger newspapers, obituaries are written only for people considered significant. In local newspapers, an obituary may be published for any local resident upon death. A necrology is a register or list of records of the deaths of people related to a particular organization, group or field, which may only contain the sparsest details, or small obituaries. Historical necrologies can be important sources of information.
Two types of paid advertisements are related to obituaries. One, known as a death notice, omits most biographical details and may be a legally required public notice under some circumstances. The other type, a paid memorial advertisement, is usually written by family members or friends, perhaps with assistance from a funeral home. Both types of paid advertisements are usually run as classified advertisements.Pallor mortis
Pallor mortis (Latin: pallor "paleness", mortis "of death"), the first stage of death, is an after-death paleness that occurs in those with light/white skin.Post-mortem interval
Post-mortem interval (PMI) is the time that has elapsed since a person has died. If the time in question is not known, a number of medical/scientific techniques are used to determine it. This also can refer to the stage of decomposition of the body.Rigor mortis
Rigor mortis (Latin: rigor "stiffness", mortis "of death"), or postmortem rigidity, is the third stage of death. It is one of the recognizable signs of death, characterized by stiffening of the limbs of the corpse caused by chemical changes in the muscles postmortem. In humans, rigor mortis can occur as soon as four hours after death.Skeletonization
Skeletonization refers to the final stage of decomposition, during which the last vestiges of the soft tissues of a corpse or carcass have decayed or dried to the point that the skeleton is exposed. By the end of the skeletonization process, all soft tissue will have been eliminated, leaving only disarticulated bones. In a temperate climate, it usually requires three weeks to several years for a body to completely decompose into a skeleton, depending on factors such as temperature, humidity, presence of insects, and submergence in a substrate such as water. In tropical climates, skeletonization can occur in weeks, while in tundra areas, skeletonization may take years or may never occur, if subzero temperatures persist. Natural embalming processes in peat bogs or salt deserts can delay the process indefinitely, sometimes resulting in natural mummification.The rate of skeletonization and the present condition of a corpse or carcass can be used to determine the time of death.After skeletonization, if scavenging animals do not destroy or remove the bones, acids in many fertile soils take about 20 years to completely dissolve the skeleton of mid- to large-size mammals, such as humans, leaving no trace of the organism. In neutral-pH soil or sand, the skeleton can persist for hundreds of years before it finally disintegrates. Alternately, especially in very fine, dry, salty, anoxic, or mildly alkaline soils, bones may undergo fossilization, converting into minerals that may persist indefinitely.