Down to earth.

We’re all familiar with the parachute analogy to criticize the notion that randomized trials are the gold standard for absolutely any intervention. Well, the Brits are at it again with an actual randomized trial reporting no benefit with parachute use among subjects jumping from a plane. The catch? They only enrolled participants on parked planes. The authors’ cheeky point is that, while pre-existing convictions about an intervention don’t negate the need for confirmatory data, they can negate the applicability of results due to crippling selection bias. | Yeh, BMJ 2018