It doesn't take an advanced degree in statistics to know that life is full of risk and that some activities are riskier than others. No one's going to argue that walking down the street is less risky than skydiving, but how do they truly compare to one another? To answer that, we need a unit of measurement to keep everything mathematically sound, and that's where the aptly named micromort comes in.
The micromort was the brainchild of engineer Ronald A. Howard from Stanford University, who wanted an accurate unit to gauge the 'risk of death' we experience on a regular basis. Basically, a micromort stands for a one-in-a-million chance of death, reports Esther Inglis-Anrkell for io9. So, if you have 2 micromorts, you have a two-in-a-million chance of dying.
To better understand that, let's look at marathon running. According to data from the US National Library of Medicine, 0.75 male marathon runners out of 100,000 will die while racing. When adjusted, this means that roughly 7.5 marathon runners out of 1 million will die during a race. Since micromorts represent a one-in-a-million chance, running a marathon would equal 7.5 micromorts (for men), which is quite low compared to other sports.
Using this unit, we can evaluate almost any activity we want. According to Cambridge University's Understanding Uncertainty site, getting out of the bed every morning for an 18-year-old costs roughly 1 micromort. For a 90-year-old man, that number skyrockets to a whopping 463 micromorts, which means that getting out of bed kills roughly 463 90-year-old men out of one million.
The numbers are interesting to look at while comparing different sports and everyday activities. The average scuba dive is around 8 micromorts, depending on experience. Base jumping comes in at 430 micromorts per jump while mountain climbing in the Himalayas is rated at 12,000 micromorts per climb.
However, what's really disheartening is that these numbers are all added together per day. Say, for example, you're a 90-year-old man who woke up, climbed Mount Everest, then base jumped off - all of that comes to about 12,893 micromorts, which is still slightly off because there were other activities involved that day like going to the bathroom and eating, which of course come with their own (relatively low) risks.
Not to mention that if getting out of bed raises a 90-year-old's micromorts so much, climbing a mountain exponentially increases it further.
To get the your full micromort rating for a day, you have to look up the stats and calculate your grand total. The more you do, and the more adventurous you are, the higher you micromorts because it seems like everything is out to kill us. But hey, that's life.
The funny thing is that Howard wanted a better, less-scary way of looking at risk. Instead, we now have the tools to freak ourselves out.
How about the original question? How much riskier is skydiving than a stroll down the street? Quite a bit, actually. One skydive is about 10 micromorts, while you'd have to walk at least 17 miles (27.2 kilometres) to even earn 1.