Last weekend, I joined four other statisticians in a skydive. We were treated to marvellous views of Melbourne as we floated down to the ground early on Saturday morning.

Some of our colleagues were disturbed to hear of our plans, and even thought it reckless to be putting so much local statistical expertise at risk! That got me thinking, how dangerous was it? Of course, I waited until after our skydive to look this up…

A convenient measure of this type of risk is a micromort: representing a one-in-a-million chance of dying due to a given event or activity. We can look back at historical data to get a rough assessment for any activity. For skydiving, it is about 8 micromorts. This is averaged across a large number of skydives. In our case, since we were jumping in tandem with very experienced instructors, I would guess our risk would be lower than this average.

How does this compare to other, more familiar, activities?

Running a marathon or doing a scuba dive are of similar risk to a skydive. As is riding a motorbike for 80 km (Melbourne to Geelong), driving a car for 3000 km (Adelaide to Darwin) or flying 13,000 km (Melbourne to Seattle). I don’t know if that would reassure my risk-averse colleagues, or terrify them to stay at home.

Some much riskier activities are BASE jumping (430 micromorts) and climbing Mount Everest (40,000 micromorts). I’m definitely staying away from these!

For more on this topic, I recommend Hassan Vally’s 2017 article in The Conversation on how deadly our daily activities are.

A version of this article was published in the 16 March 2023 edition of SSA’s weekly bulletin.