Many of us participate in activities and sports that are at least somewhat dangerous.  However, most of us also do not have a full appreciation of how risky these activities really are, especially compared to other things that we could be doing instead.

We just love our favorite pastime and facing up to its risks can be stressful because we also want to be safe while having fun. Psychologists call this type of stress “cognitive dissonance”, and we intuitively look for ways to remove the discomfort of our conflicting emotions, often by downplaying the risks to ourselves and to others. 

E.g., when I became a glider pilot some 35 years ago, my instructors used to proclaim that “the most dangerous aspect of the sport is the drive to the airport”.  This was a widely held belief at the time even though it could not have been further from the truth. And while the slogan was famously debunked by the prominent German pilot Bruno Gantenbrink in his speech “Safety comes first“, our instinct to downplay the risks to ourselves (and to others) has of course remained.

Given our natural inclination to deceive ourselves, it is not surprising that good data about the factual risks of many activities can be difficult to come by.  And even if data are reported, they are often accompanied by statements that soften, blur, or contradict the facts, frequently through the use of misleading comparisons.

Here is just one such example from scuba diving in which the author asserts that scuba diving is safer than driving a car. She does this by comparing the statistic that 1 in 5,555 people were killed in a car accident in 2008 with the statistic that only 1 out of 212,000 dives ended deadly.  Did you catch the fundamental flaw?  The comparison would be ok only if each driver would drive just once a year.  In reality, each driver makes on average 2 trips per day, i.e. 730 car trips per year, which means that the 5,555 drivers drove in aggregate about 4 million times (5555*730).  I.e., 1 in 4,000,000 drives ended deadly vs 1 in 212,000 dives. By this – still not perfect, but definitely more comparable – measure diving isn’t safer than driving but instead about 19x more dangerous! No matter the sport or activity, you’ll quickly find similar examples of apples to oranges comparisons and a conscious or subconscious attempt to downplay the risks.

When I looked for data on risky sports and activities, I also found the other extreme: a Google search will return plenty of articles listing “the most dangerous sports in the world,” almost all of which try to make most sports sound insanely dangerous. However, more often than not these articles are just click-bait to generate ad revenue and lack any serious effort to get to the facts.  Even the most well-intentioned ones that actually quote their sources tend to suffer from one of two major problems: either they lack a common denominator and therefore compare stats that are just not comparable; or they use a denominator that isn’t all that meaningful such as the general population while ignoring the differences in participation rates among different sports.

I wanted to know the honest truth and so I set out to do the research myself.  The most important decision that I had to make at the outset was to select the most appropriate basis of comparison and hence, what denominator to use.  I concluded that the most meaningful datapoint to me is the risk of dying (and the risk of getting injured) per hour of participating in a particular activity.  There are two reasons I picked this risk per participation hour as the most sensible base of comparison: First, it allows me to compare different choices for my spare time, e.g., the risk of spending an afternoon riding a mountain bike vs the risk of spending the same afternoon flying a sailplane. Second, it gives me a sense of how serious the risk really is and therefore how carefully I should prepare to mitigate it.

The graphic that we’ll get to below shows what I came up with.  To facilitate the readability of the comparison, I benchmarked all activities against traveling on commercial airlines, which happens to be one of the safest things you can do when you leave your home:  only once in 10 million passenger hours (i.e., once in 1,141 years) will a passenger die when traveling on a commercial airline.  In other words, the chance of a person dying within their next 1,000 participation hours is only 0.01%.

Other activities that I participate in regularly such as driving, cycling, skiing (on and off piste), or marathon running aren’t nearly as safe as traveling on an airliner but they are still quite safe.

Unfortunately, my favorite sport, flying sailplanes, aka soaring, is one of the more dangerous activities.  There are no reliable participation data available for the US but I found quite solid information for Germany and France where soaring is much more practiced than in the US.  In both countries the sport has a fatality rate of 1 in 50,000 participation hours; i.e., the risk of dying within the next 1,000 hours of participation is 2%, about twice as high as the risk involved in riding motorcycles.  It also means that an active pilot, who flies about 100 hours per season, has a 1 in 50 chance of dying in the sport within the next decade, and it makes soaring about 200 times more dangerous as traveling on a commercial jet. Other air sports tend to have similar risks:  flying powered airplanes is just a little bit safer whereas hang-gliding and paragliding are somewhat more dangerous.

Some of the data surprised me.  E.g., I found driving, skiing, and cycling to be safer that I expected, whereas climbing the Tetons and especially Mt Everest is actually much more dangerous than I anticipated.  Not surprising to me was the insanely high risk involved in Base Jumping, which is shown to be 480,000 times more dangerous than commercial aviation, with an expected death per 21 hours of participation, and practically no chance at all to survive the next 1,000 hours of flying through the air.  If you’re a Base Jumper you are likely to complain that my methodology of counting only the short duration of the jump (and, e.g., not the time you spend climbing up the mountain) puts your sport into an unfair light.  To that I say feel free to count differently if you want to convince yourself that jumping is safer than it really is.  As I pointed out above, you certainly won’t be alone in your desire to deceive yourself.

Unfortunately, all the information in the chart below only refers to the risk of death and does not account for the risk of injuries.  The reason is simply the fact that data about injuries are extremely unreliable since the great majority of sport injuries are never reported and/or accounted as such.  (The omission of injury information also means that activities that tend to have a relatively high injury to death ratio (e.g. skiing, equestrian eventing, marathon running, riding motorcycles, hang gliding, paragliding, downhill mountain biking) might look relatively safer than they really are, and activities that have a relatively low injury to death ratio (e.g. general aviation, soaring, skydiving) might appear relatively more dangerous than they really are.)

Without further ado, here is the chart:

Another way to look at the same data is to compare them to the normal risk of dying (of any cause) at different life stages.  Life insurance companies keep track of these risks as they seek to adjust their premiums based on the age of the insured.  It should be intuitive that an 18 year old person has a much lower risk of dying within their next 1,000 life-hours than a 90 year old.

Below is a chart that shows how this normal risk of death increases as you get older. E.g, the odds that an average 18-year-old American male will die within their next 1,000 life-hours is about 0.01%.  This happens to be exactly the same odds as traveling on a commercial airliner, once again illustrating how save commercial air travel has become. A 90-year-old male, by comparison, has a 1.9% chance of dying within their next 1,000 life hours.  You can see how the slope of the curve remains fairly flat until the age of 50, and how it really steepens around 75. If someone manages to survive until the age of 119, their odds of dying within the next 1,000 life-hours will have risen to 10.2%.

(The source of this information is the US Social Security Administration.  Note that they report the risk of dying within the next year, which I converted to the
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