Beginning to look a lot like Christmas

In particular, the Christmas issue of the medical journal BMJ, which traditionally includes some research and commentary making serious points in a somewhat non-standard way.

As you may know, a famous BMJ Christmas research paper from 2003 summarised all the existing randomised trials of parachute use when jumping from a plane. There were none.  The paper concluded

 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.

The paper was pushing the idea that a lot of interventions are so obviously beneficial as to not need evaluation. This idea hasn’t gained much ground since then; probably the reverse. So, it’s appropriate that the highlight of this year’s Christmas issue is a randomised controlled trial of parachute use when jumping from a plane, measuring the effect (impact?) on the risk of being dead or seriously injured, both immediately after the jump and 30 days later.

The trial found no suggestion of a difference between the participants who used a parachute and the ones who used an ordinary North Face backpack. As the researchers note, however,

the trial was only able to enroll participants on small stationary aircraft on the ground, suggesting cautious extrapolation to high altitude jumps.

That is, the paper is making the point that randomised trials often recruit very non-representative sets of people, and this especially true when the medical community, rightly or wrongly, thinks it knows the treatment is effective.