Calculating the Risk of Death Through Micromorts
In the 1970s, researchers at Stanford University developed the concept of the “micromort” to measure the likelihood of sudden death. We use amperes to measure electrical current, and Celsius or Fahrenheit to measure temperature. The micromort is used by statisticians to calculate the probability of a one-in-a-million chance of experiencing sudden death. It gives us a handy way of comparing the risk of various activities, although we all know intuitively that running with the bulls in Pamplona carries more risk than doing The New York Times crossword.
Here’s The Sydney Morning Herald: “If something exposes you to a micromort of risk, this means it exposes you to a one-in-a-million chance of dying.”
How about some context please? Okay. Flip a coin in the air 20 times and the odds of it coming down heads every time is about one million to one. (Actually, it’s one in 1,049,000.) So, one micromort means the probability of your life being snuffed out suddenly is low.
The BBC has calculated the micromorts from a general anaesthetic. Statistically, this happens about once in every 100,000 operations, or 10 deaths per one million operations carried out under general anaesthetic. That is 10 micromorts. But, you only have to go skydiving once to rack up 10 micromorts, or ride a motorcycle for just 96 km (60 miles) for the same score.
The risks associated with everyday life can be divided into acute and chronic.
Being out on the golf course on a sultry summer afternoon carries a certain level of risk that can be calculated.
We hear of golfers being killed by lightning strikes but this happened only nine times in the United States between 2006 and 2016. The chances of this happening are one in 600,000, that means about 1.7 micromorts.
Heart attacks are another golf course problem, although statistics on how often they happen are hard to come by. However, golfwisconsin.com notes that “Golf courses are rated in the top five public venues in which cardiac arrests occur.”
And, the chances of surviving a heart attack on a golf course are slim; about five percent. The defibrillator, if the golf course even has one and many don’t, is in the clubhouse and the victim is in a bunker on the seventh fairway. Every minute in delay of starting resuscitation means a 20 percent increase in fatality.
On the plus side, a Swedish study found that golfers live, on average, five years longer than non-golfers (ABC Health and Wellbeing). However, before golf gets the complete credit for the extra years, let’s remember that golf is a pastime of the affluent; people likely to have better diets and health care than the average.
Chronic Risk and Microlives
Chronic risk is what caused our golfer to lie face down in the sand trap as his life ebbed away. His lifestyle built up the number of micromorts in his ledger. He smoked a pack of cigarettes a day, drank too much, and had a high-fat, high-salt diet. All of these factors carved years off his expected lifespan. This can be measured in “microlives,” a unit of time that lasts 30 minutes.
We all live our lives at different speeds. Understanding Uncertainty.org explains how our heavy-smoking golfer raced through his life more quickly than a non-smoker: “… someone who smokes 20 a day is using up around 10 microlives, which could be loosely interpreted as their rushing towards their death at around 29 hours a day instead of 24.” Similar calculations can be made about alcohol use that mounts up and knocks a few months or years off your life.
The BBC adds that “… for every extra 5kg you are overweight, it will cost you around one microlife a day.”
Would you rather swim off the coast of Australia where sharks are known to live or run a marathon? The option of sitting in a recliner and knitting sweaters for the grandkids is not on offer.
If it wasn’t quite beyond the ability of a certain elderly and chubby writer he would choose the marathon. He would be wrong to do so.
One average, between three and four swimmers are killed by sharks in Australian waters each year. Australia’s population is around 24 million, so that means about a one in eight million chance of an unfortunate encounter with Jaws.
Calculation delivers 0.125 micromorts; whereas, marathoners drop by the dozen every year and increases each runner's chance of dying by seven micromorts per outing. That’s a 56 times greater chance of dying with your Nikes on than in your bathers.
Of course, many variables come into play. An 18-year-old man getting out of bed in the morning costs about one micromort. But, a 90-year-old man performing the same activity faces 463 micromorts.
There are those among us who need a couple of shots of liquor or a Valium before getting on a plane. However, they won’t think twice about getting into Uncle George’s car for a ride to the airport.
Here’s The Irish Times to put some perspective on relative risk: “The lifetime risk of dying in an air crash is 1 in 7,178, according to the National Safety Council of America. This is far lower than the 1 in 98 chance of dying in a car crash or the 1 in 701 chance of being killed as a pedestrian.”
The perceived risk of flying is created by media coverage of plane crashes. They are few and far between but when they happen they become the lead item on national news and are repeated over several cycles. A fatal car crash will be covered locally, but will soon fade from view.
This disparity in coverage tends to cause people to grossly overestimate one risk and grossly underestimate another.
But, if you want to try to beat the odds, climb Mount Everest. Between 1922 and 2012 there have been 5,656 successful ascents. During that same period 223 people have died trying. The micromort risk works out to 37,932 per attempted ascent.
Bodies Litter the Slopes of Everest Because There is no Practical Way of Recovering them.
Micromorts and microlives are different. If you ride your Yamaha crotch-rocket to the top of a cliff, jump off it wearing one of those wing suits, and survive you will have racked up a hefty micromort score. When you wake up the next morning your slate is clean; you do not accumulate micromorts. However, microlives add up, in a negative way. Here’s how the folks at Understanding Uncertainty put it: “It’s like a lottery where the tickets you buy each day remain valid for ever - and so your chances of winning increase every day. Except that, in this case, you really don’t want to.”
Micromort values can vary from country to country. The risk of being murdered in the United States is 48 micromorts per year, in Canada it’s 15.
(As an aside, in 1977, 74-year-old Bing Crosby had just finished a round of golf in Madrid. He had shot an 85 and said to his companions “That was a great game of golf, fellas. Let’s go have a Coca-Cola.” Then, he collapsed and died from a heart attack.)
- “Golf: a Game of Life and Death.” Peter Lavelle, ABC Health and Wellbeing, September 4, 2008.
- “What Can Golf Courses Do To Save Heart Attack Victims?” Brian Weis, golfwisconsin.com, undated.
- “What’s Most Likely to Kill You? Measuring How Deadly our Daily Activities Are.” Hassan Vally, The Conversation, February 21, 2017.
- “Microlives: A Lesson in Risk Taking.” David Spiegelhalter, BBC Future, February 16, 2012.
- “Which Do You Think Is Riskier?” Niamh Dornan, Irish Times, July 12, 2012.
- “Microlives.” Understanding Uncertainty.org, November 22, 2011.
- “This Unit of Measurement Figures Out How Likely You Are to Die Today.” Josh Hrala, sciencealert.com, March 25, 2016.