By SAURABH JHA
Sequels generally disappoint. Jason couldn’t match the fear he generated in the original Friday the 13th. The sequel to the Parachute, a satirical piece canvassing PubMed for randomized controlled trials (RCTs) comparing parachutes to placebo, matched its brilliance, and even exceeded it, though the margin can’t be confirmed with statistical significance. The Parachute, published in BMJ’s Christmas edition, will go down in history with Jonathan Swift’s Modest Proposal and Frederic Bastiat’s Candlemakers’ Petition as timeless satire in which pedagogy punched above, indeed depended on, their absurdity.
In the Parachute, researchers concluded, deadpan, that since no RCT has tested the efficacy of parachutes when jumping off a plane, there is insufficient evidence to recommend them. At first glance, the joke was on RCTs and those who have an unmoored zeal for them. But that’d be a satirical conclusion. Sure, some want RCTs for everything, for whom absence of evidence means no evidence. But that’s because of a bigger problem which is that we refuse to acknowledge that causality has degrees, shades of gray, yet causality can sometimes be black and white. Somethings are self-evident.
In medicine, causation, even when it’s not correlation, is often probabilistic. Even the dreaded cerebral malaria doesn’t kill everyone. If you jump from a plane at 10, 000 feet without a parachute death isn’t probabilistic, it is certain. And we know this despite the absence of rigorous empiricism. It’s common sense. We need sound science to tease apart probabilities, and grayer the causality the sounder the empiricism must be to accord the treatment its correct quantitative benefit, the apotheosis of this sound science being an RCT. When empiricism ventures into certainties, it’s no longer sound science. It is parody.