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by vamos_davai 2741 days ago
Would you indicate this is a satirical article? Half the time I was looking for jump height or understanding if adding parachutes to commercial aircraft that suddenly experienced breakage such as a missile would improve passenger survival.
6 comments

The fact that this isn't immediately tagged as satirical and requires actually reading the article and fully understanding the context (rather than just reading the headline and making a quick assumption) is pretty much the entire point of the "study" and the authors of it. Marking it as satirical would sabotage the purpose.
Indeed, this is half the point of the BMJ Christmas Issue, which happens every year.
Yeah, tried reading the summary and then the first few comments and I was still confused about what the heck they were talking about.
Anecdotally I find the slow realization that something is satire to be an integral part of it's entertainment value.
That was, after all, how something like A Modest Proposal was structured. You were supposed to believe the author was serious at first. That's an important element to a lot of satire.
I've done over 900 jumps so I can fill you in, no references ATM because I'm on my phone.

If you jump with a parachute, you will see chance of death go from 0% at zero feet, to approximately 100% at 35 feet. From there, it will remain near 100% until you reach about 600 feet, which is about the minimum distance it takes a parachute to open. Above 1000 feet and chance of death floors out near 0%

35 ft is a little pessimistic, the LD50 is 10.5m (~35 ft) for those with head and chest injuries, and 22.4m (~75 ft) for those without. Which is surprisingly far.

In patients with head and chest injuries, a 50% mortality rate was estimated to occur at falls from 10.5m, compared to 22.4m in those without injuries to head or chest

https://www.ncbi.nlm.nih.gov/pubmed/22860503

Studies like this don't provide good data points for "if you jump[...]" as the GP mentioned. The data is gathered from people who either accidentally fell, or intentionally jumped not intending to live.

They can't just randomly recruit people and have them jump to their near-certain deaths from ever increasing heights due to pesky medical ethics boards.

This matters because a person who's forced to jump from a significant height out of desperation (e.g. to avoid a fire) is likely to take certain precautions that people who accidentally fall don't take, and those trying to kill themselves intentionally avoid.

I distinctly remember seeing a video of a jump my unit did in Honduras (right before I got there) where someone on the ground with a camera followed someone burning-in who opened their reserve at ~50-75ft and "walked" away with just a broken tailbone.

There was another case where someone "successfully" burned-in from 800ft (where we did all our jumps from) and survived because they did a proper landing or, perhaps, just pure luck.

From what I remember there were only a couple jump-related fatalities in the 3 years I was on jump status and the 82nd did something like a million jumps a year...which says a lot because if we went 82 days without a fatality we would get a day off and in 3 years we reached that goal exactly once.

”approximately 100% at 35 feet”

Not sure about that. Although chance of death would be significant, there are many cases of people surviving falls from greater heights.

There are of course extraordinary cases. There is that last tiny fraction of survivors.

But really, falling sucks. There is a reason working in solar is more deadly than working in nuclear. And the reason is occasionally an installer falls off of a roof.

Some people survive such falls but they typically require extensive surgery and long hospital stays. They often suffer serious long-term cognitive or physical deficits. It's not a fun way to survive.
99.9% is approximately 100% ;) But yeah, that's a number I just pulled out of...thin air.
Will jumping from high enough without a parachute ever decrease the odds of death than they the odds of death at a lower altitude?
Theoretically, once you're high enough that you reach terminal velocity, any additional altitude does not increase your speed but does increase your time in the air, potentially giving you more time to navigate towards a more favorable landing site (evergreen grove, mountainside covered in deep snow, pile of 45 mattresses that happens to be outside, etc).
If you're far enough away you'll suffocate before reaching the ground.
Not that I know of. Maybe, if you jump from high enough that you pass out due to lack of oxygen, and you land in a manner that benefits from you being a ragdoll vs an actively bracing person, then it could help, but that seems unlikely(you'd probably also wake back up before you hit the ground, as I've heard stories about this happening to WWII pilots).

But overall, I believe it is better to be conscious. If you are falling from 3 miles up, you can glide to maybe 1 mile in any direction. This gives you the chance to try to land in a snow drift, in some mud, maybe a hay bail, or even a thick shrubbery, etc.

First you must find... another shrubbery! Then, when you have found the shrubbery, you must place it here, beside this shrubbery, only slightly higher so you get a two layer effect with a little path running down the middle. ("A path! A path!") Then, you must cut down the mightiest tree in the forrest... with... a herring!
Not for humans. You're thinking of cats.

https://en.wikipedia.org/wiki/High-rise_syndrome

This is almost certainly survivorship bias[1]. Only middle-height cats that might theoretically survive are going to be taken to a veterinarian; the cats that fell from higher heights were not included, because they were "obviously dead". Which makes "high-rise syndrome" an example of the exact type of bias discussed in this paper.

[1] https://en.wikipedia.org/wiki/Survivorship_bias#In_cats

> Strangely, cats that fall from a height under 6 stories have more severe trauma than those that fall from over 6 stories.

So, the theory is, if a cat falls from a height above 6 stories they either have less severe injuries or are just dead so the owner just doesn't bring them to the vet?

>>6 stories they either have less severe injuries or are just dead so the owner just doesn't bring them to the vet

I would guess that at that height something must've broken the fall such that the cat suffered almost no injuries. I really don't see how the cat would survive the fall otherwise.

There is obviously an element of satire, but are the authors are also trying to make some sort of statement about clinical trials?
Clinical medicine, especially, is often paralyzed by "We don't have an RCT about this particular circumstance therefore we know nothing."

This article is making a comment about that.

Yes. Consider trialling a new drug that is supposed to prevent/cure a terrible disease, and has a well explained mechanism of effect, supported by clinical results of some % of sick people no longer being sick after treatment.

If you want an RCT you need a control group who will be subjected to the horrible disease with standard treatment (and sometimes a group with no treatment), and a group subject to the experimental treatment. Who will volunteer for this trial? Perfectly health people? Or people with the disease?

Like, maybe the measles vaccine is all just placebo effect and good sanitation and handwashing practices. Can we do an RCT where we inject some children with saline instead of vaccine, then see what happens?

Because we can't be certain the children of crunchy hipsters who don't get immunised get measles is related to lack of immunisation, it might be they expose themselves to exotic strains by taking exotic holidays.

Isn't satire always trying to make a serious statement? Or at least, good satire?
Jump height is even in the abstract. You have to read it though, skimming won't work.
"The PARACHUTE trial satirically highlights some of the limitations of randomized controlled trials."