Can a Parachute Save Your Life? Not According to Science.

This priceless paper, published in the BMJ, makes us take a good, hard look at our assumptions. Sure, we think that parachutes save lives. But in the end, as this study shows, the evidence is weak.

Here is a paper that will either make you like scientists a little more, or a lot less. "Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised control trials," has in its title my favorite scientific euphemism - "challenge." When scientists rub viruses in your face, you are being "challenged" with a virus. When they let mosquitoes bite your hand, you are being "challenged" with infection vectors. And when they drop you out of a plane, you are undergoing a "gravitational challenge." This paper adds to my glee by saying that the death and major trauma are "related to," the gravitational challenge, as if we still haven't hammered out the fact that gravity makes people fall.

Then again, the whole point of this study is that we haven't hammered out much. Sure, we think that parachutes are helpful after people hurl themselves out of airplanes, but can we be sure? In its conclusion the study states:

As with many interventions intended to prevent ill health, the effectiveness of parachutes has not been subjected to rigorous evaluation by using randomised controlled trials. Advocates of evidence based medicine have criticised the adoption of interventions evaluated by using only observational data. We think that everyone might benefit if the most radical protagonists of evidence based medicine organised and participated in a double blind, randomised, placebo controlled, crossover trial of the parachute.

A double blind, randomized, placebo controlled crossover trial of the parachute means that the "advocates of evidence based medicine" would be put on a plane, given packs, and made to hurl themselves toward the ground. Neither the givers or the receivers of the packs would know which ones held parachutes, and which held "placebos."

This is satirizing the view of people who feel observational studies - studies in which everyone is treated with the experimental medicine and the response of the entire group is evaluated - aren't clear enough or rigorous enough to prove that a drug works. True, these studies sometimes lack the clarity of a perfect randomized double-blind study, but as we see with the parachute, sometimes the results are pretty clear anyway. And in a life-or-death situation, no one wants to take the chance on a placebo. In other words, the "advocates of evidence based medicine" are being "challenged" with a little sarcasm.

The best part is at the end. The contributors to the paper are listed as Gordon C S Smith, and Jill P Pell. The final note on the paper reads, "Contributors GCSS had the original idea. JPP tried to talk him out of it. JPP did the first literature search but GCSS lost it. GCSS drafted the manuscript but JPP deleted all the best jokes. GCSS is the guarantor, and JPP says it serves him right."

Image: U.S. Air Force photo by Tech. Sgt. Jeremy T. Lock