Researchers Show Parachutes Don't Work, But There's A Catch (npr.org)

Reader Beeftopia shares a report: Research published in a major medical journal concludes that a parachute is no more effective than an empty backpack at protecting you from harm if you have to jump from an aircraft. But before you leap to any rash conclusions, you had better hear the whole story. The gold standard for medical research is a study that randomly assigns volunteers to try an intervention or to go without one and be part of a control group. For some reason, nobody has ever done a randomized controlled trial of parachutes. In fact, medical researchers often use the parachute example when they argue they don't need to do a study because they're so sure they already know something works. Cardiologist Robert Yeh, an associate professor at Harvard Medical School and attending physician at Beth Israel Deaconess Medical Center, got a wicked idea one day. He and his colleagues would actually attempt the parachute study to make a few choice points about the potential pitfalls of research shortcuts.

They started by talking to their seatmates on airliners. [...] In all, 23 people agreed to be randomly given either a backpack or a parachute and then to jump from a biplane on Martha's Vineyard in Massachusetts or from a helicopter in Michigan. Relying on two locations and only two kinds of aircraft gave the researchers quite a skewed sample. But this sort of problem crops up frequently in studies, which was part of the point Yeh and his team were trying to make. Still, photos taken during the experiment show the volunteers were only too happy to take part. The drop in the study was about 2 feet total, because the biplane and helicopter were parked. Nobody suffered any injuries. Surprise, surprise. So it's technically true that parachutes offered no better protection for these jumpers than the backpacks.

Comments

This

[Anonymous Coward]

is the dumbest fucking thing I've read today.

Re:This

[Zocalo]

And from this I can conclude that either you did not actually read it, failed to comprehend what you read, or (just possibly) really took issue with how they presented their point, despite the Christmas issue of BMJ being intentionally lighthearted.

Hint: this has nothing to do with people jumping out of planes and everything to do with the extent that medical researchers assume things are so rather than actually demonstrate that is the case.

Re:This

[MikeDataLink]

is the dumbest fucking thing I've read today.

Then you quite simply do not understand the point of it smarty pants.

At 2ft the parachute provided no better protection than an empty backpack. This is a silly of course, but the point is that in medical research when shortcuts are taken they miss the point and come to a conclusion like this on something that actually DOES matter.

It's an analogy to help the layman understand. Get with the program.

Re: This

[jd]

Frozen salmon have brain activity, according to research winning an Ignobel prize in its demonstration of poor controls and poor statistical analysis in fMRI studies.

So, yes, null results are published and are valuable, when they show up flawed methodology.

Re: Bullshit is bullshit.

[jd]

Why would you send people?

Crash test dummies loaded with sensors would give you much more information.

Re: Why are the most educated people dumb as brick

[jd]

Then you didn't understand it. Which, in all honesty, doesn't reflect on them.

The takeaway

[Rick Schumann]

If someone doesn't inherently understand what the real takeaway from this story is, then I question their IQ, their capacity to think critically, or both.

Their point was selecting patients

[raymorris]

Their point was that the results of my medical study very much depend on which patients are selected for the study.

Those who are likely to recover probably won't show much benefit from the treatment, because they were going to be okay anyway. Those who have a really bad prognosis may not show much benefit because they are past the point of no return, beyond help. In other studies, using patients who have a bad prognosis may exaggerate the benefits of the treatment by neglecting to include the fact that most people would be fine without the treatment. That is, the study might seem to indicate "the treatment doubles your chance of survival", but that's not true if the 90% of people with mild cases aren't included in the study.

Here, they used subjects with a very mild case of "jump out airplane". The study showed that parachutes provide no benefit - but only because the study participants had a very mild degree of the problem. One could also do a study of extreme cases and discover parachutes don't work for jumping out of an SR-71 at cruise. The study would need to include participants with varying "a priori" prognosis, and probably run stats for each class - good prognosis, bad prognosis, and in between.