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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.
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.
is the dumbest fucking thing I've read today.
My favorite study along these lines was a randomized selection of men, half of whom were injected with steroids and half got no steroids. Neither group showed muscle gains during the study period. Not mentioned in the headline was that neither group lifted weights or engaged in any exercise. So in a sense the headline was true: just taking steroids doesn't give you big muscles. But the guys in my gym who took steroids got big because they were able to recuperate faster from heavier workouts.
....just guess.
For some reason, nobody has ever done a randomized controlled trial of parachutes.
It would be unethical to send people to their certain deaths when gravity has been sufficiently tested to the point where it is accepted as a physical constant.
However, I'm sure ethicists would be willing to look the other way if all idiots complaining about a lack of controlled trial were used as the subjects of such a test.
Anons need not reply. Questions end with a question mark.
It's making a point about medical researchers making assumptions and/or cherry picking situations/test candidates that will skew results towards a preferred/anticipated outcome. The Christmas issue of BMJ is intentionally lighthearted, something that probably should have been made clearer in TFS to avoid the amount of "WHOOSH!" that's going on.
UNIX? They're not even circumcised! Savages!
The point is that flawed assumptions about "common sense" stuff are a major cause of flawed results.
Indeed, it's the primary cause of irreproducible results.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
It was actually just one guy. And he wasn't using his clothing to brake his descent. He was using it to stabilize his descent so that he would hit the water feet-first with his legs crossed. Also, if I recall correctly, Rama did not spin fast enough to produce a full Earth gravity at even the lowest level of the cylinder. And the plot point was that the jumper had crashed after flying down the zero-g axis of Rama to explore the top of an otherwise unscalable mesa (And, therefore, would be under even less initial acceleration owing to his hight.).
Imagine all the people...
Not if it reminds people how they are constantly lied to via fancy language and assumption manipulation...
BLS numbers on the economy? Every politician ever? Parse them carefully and many take this to high art - not actually lying but saying things in a way that you thought you heard what you wanted to hear. All marketing? Man, I tried all that aftershave, toothpaste, hair gel and treament, still didn't "get the girl"...(you're supposed to know that's a joke).
Why guess when you can know? Measure!
Then you didn't understand it. Which, in all honesty, doesn't reflect on them.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Arthur C Clarke, not Asimov.
And, yes, it's all about terminal velocity for a given aerodynamic configuration.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
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.
The point is that flawed assumptions about "common sense" stuff are a major cause of flawed results.
Except that the "common sense" assumption about the outcome of this experiment is exactly what actually happened.
Nobody with "common sense" would assume a parachute would be helpful for a two foot drop.
My favorite study along these lines was a randomized selection of men, half of whom were injected with steroids and half got no steroids. Neither group showed muscle gains during the study period. Not mentioned in the headline was that neither group lifted weights or engaged in any exercise. So in a sense the headline was true: just taking steroids doesn't give you big muscles. But the guys in my gym who took steroids got big because they were able to recuperate faster from heavier workouts.
My favorites are medical studies on vitamins and supplements and other related.
For example, a 4-week study of Glucosamine/Chondroitin supplements that had no effect on joint pain of Rheumatoid Arthritis patients.
Conclusion? G/C supplementation has no effect.
Reality? We don't really know. 1) G/C supplementation is to make stronger and healthier joints by supplying building blocks not otherwise found in the diet, and 2) Joints have no blood vessels, so change very slowly. Typically 7 weeks or more would be needed to see an effect.
Compare with: St. John's Wort depression studies lasting less than 4 weeks (medical depression meds sometimes take as much as 6 weeks to show an effect), Omega 3 fatty acid supplementation studies in healthy adults (instead of children/adults with behavioral issues), and so on.
Nutrition studies are particularly useless. My favorite example is the guy making Soylent started out by asking the simplest question: what nutrients do we actually need to be healthy?
The answer is: No one knows, the literature is a bewildering mess of confusing and contradictory results, and nutrition experts have differing views.
(If you don't believe me, see if you can determine a) the *minimum* amount of vitamin D needed daily to prevent disease, and b) the *optimum* amount needed for best health. Bonus points if you can determine whether mega doses of Vitamin D are toxic. Supplemental bonus points if you can determine whether mega doses of Iodine are toxic.)
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.
I mean, unless I've missed it, there doesn't seem to be any post here thinking about how to make this "true".
Sure, the study was ridiculous and intended to make a unrelated point, but the nerds should be focusing on the fact that there have been survivors of high falls without parachutes. So the most important barrier to serious R&D has been broken - the possibility is provably there!
In looking at many of the accounts on the web of high falls, I have to discount those that had parachutes that didn't open properly or were likely within the wreckage of an aircraft for most of the fall. Those were likely slowed down by things like the drag of a defective parachute or the body of a plane.
The more intriguing accounts are the falls from high buildings. In most cases, they seem to have been helped by landing on something that absorbed some of the shock of landing. Several landed on roofs. A very intriguing one landed on the roof of a car after a fall of 22 stories and "walked away" with only a broken elbow.
One can imagine that these folks likely benefited from some combination of positioning their bodies for high drag and/or maneuvers that translated vertical speed to horizontal speed that was bled off by traversing more air distance and landing in some particular way on a surface that absorbed a lot of the shock.
So how might a compact device that could be carried at all times enhance the possibility of surviving something like this?
A smartphone app could detect the freefall as well as that it is still on the person. If connected to cameras around the area it might be able to spot the best surface to hit. Guiding the arms and legs of the person to positions that will fly them toward that while minimizing downward airspeed would be problematic. That would seem to require either an exoskeleton (maybe a soft motor one) built into clothing or some muscle control interface like those being experimented with on paralyzed people. So that's a stretch today. As for having to find a roof or car to hit, that might be made less necessary with something like a personal explosive airbag and some means of ground proximity detection.
It is an interesting rabbit trail that could have application in something like the construction industry, as a failsafe for climbers, military, etc.
Sounds like most of your "scientist" friends like living off of grants doing useless "research". The "researchers" here weren't making a joke, they were trying to prove a point. Unfortunately the point was already understood by anyone with half a brain. It sounds like you don't understand it yourself if you think it was hilarious.
Since some commenters appear to have misunderstood the point of the article it's worth quoting from the BMJ paper (I recommend actually reading the entire paper and/or this BMJ blog):
...
The study also has several limitations. First and most importantly, our findings might not be generalizable to the use of parachutes in aircraft traveling at a higher altitude or velocity. Consideration could be made to conduct additional randomized clinical trials in these higher risk settings. However, previous theoretical work supporting the use of parachutes could reduce the feasibility of enrolling participants in such studies.
...
Finally, although all endpoints in the study were prespecified, we were unable to register the PARACHUTE trial prospectively. We attempted to register this study with the Sri Lanka Clinical Trials Registry (application number APPL/2018/040), a member of the World Health Organization’s Registry Network of the International Clinical Trials Registry Platform. After several rounds of discussion, the Registry declined to register the trial because they thought that “the research question lacks scientific validity” and “the trial data cannot be meaningful.” We appreciated their thorough review (and actually agree with their decision).
The PARACHUTE trial satirically highlights some of the limitations of randomized controlled trials. Nevertheless, we believe that such trials remain the gold standard for the evaluation of most new treatments. The PARACHUTE trial does suggest, however, that their accurate interpretation requires more than a cursory reading of the abstract. Rather, interpretation requires a complete and critical appraisal of the study. In addition, our study highlights that studies evaluating devices that are already entrenched in clinical practice face the particularly difficult task of ensuring that patients with the greatest expected benefit from treatment are included during enrolment.
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120...ish. I fall closer to 130. I might be able to slow down to 120, but it takes some work on my part. The fastest speed on my digital altimeter is 205 mph, attained in a very steep dive at 9000 feet. I leveled into a track shortly after that, since opening a parachute at 205 mph would kill me just about as fast as not opening a parachute at 205 mph. Some of the kids I've seen flying in the wind tunnel fall at 70-80 mph. If you weigh less than 90 pounds and know how to fall slowly, I reckon you might be able to survive a terminal velocity fall if you land on the right surface. If you can find a surface that doesn't shatter some bones in the process, that'd actually be a fun party trick.
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?