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UDSkyJunkie

Debunking the "Skydiving is less dangerous than driving" myth

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This isn't true (and it's also fatalist to a scary degree.) There's no rule anywhere that says, "as a sample set becomes large, the individual trials become independent."



If I'm reading what he said correctly, he's not being fatalistic. Quite the opposite. He's showing the gambler's fallacy from the opposite side. Just because you've gambled a million times doesn't make your next time more likely to be a win.

Just like jumping a million times doesn't make your next jump more likely a death.

It's not your cumulative jumps that get you. It's just that last one... training, currency, attitude, and all other variables notwithstanding :P

jason

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If you compare more than two transportation modes, things get really weird. I was shocked when I first learned that walking is hundreds of times more deadly than driving, in terms of deaths per distance.

If this was adjusted for deaths-per-time-traveling, I'm sure it would look a lot different. Someone already mentioned this as a potentially valuable comparison adjustment for jumping vs. driving.



There are many posts of this variety, and each of them tells a different story... yeah, you can measure risk "per mile" "per minute" "per event" "per person" "per enjoyment" whatever.... my method was what made sense to me. In a given year, given the amount driving I do, and given the amount of skydiving I do, how does it stack up? saying 40,000 people died in car accidents and 40 people in skydiving accidents last year has no more meaning than saying that in 1 hour of driving you're a whole hell of a lot safer than 1 hour of freefall. Saying that on average you've exposed yourself to a greater amount of potential risk over the course of a year, while not perfect, is at least reasonable. If you don't accept that logic, fine, it don't bother my ass. If you think you have a better comparison, by all means say so. So far I haven't seen one.

To all those who commented about the assumption of a normal distribution of data, yeah you're right... that's probably not correct... maybe poisson, or einstein, or rush limbaugh came up with a more accurate distribution for skydiving, who knows. A degree in mechanical engineering taught me enough to know a normal distribution almost certainly does not apply, but not enough to know what most of those other ones mean, or if they are likley to apply. But you're really missing the point. The point is that the stats show a hypothetical "average" skydivers amount of risk. It's a good place to start, and if you analyze yourself and those around you (honestly, of course), you ought to be able to place yourself on one side of the average or the other... perhaps WAY on one side or the other. If you don't like those odds, you can change them. If you're happy with them, rock on(I am, or I wouldn't be doing what I do).
"Some people follow their dreams, others hunt them down and beat them mercilessly into submission."

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It's not your cumulative jumps that get you. It's just that last one



I think this should read "it's not the jumps you're already done that get you, it's the ones you intend to do that could"

It's true that if you've done 10,000 jumps successfully, your 10,001st is no more or less dangerous than the 1,000th. But what is also true is that if you only ever intend to do 1 more jump in your life, you're exposed to a small amount of risk, whereas if you intend to do another 10,000 you're exposed to a whole lot more. I'm in this for the long haul, so I won't fall for the argument that on each jump it's say 1 in 100,000, so I'll probably be fine. I've seen enough people die already using that theory. I look at it and say, "I want to do everything in my power to better my odds because I'm going to do another 10,000 jumps in my life." And let me tell you how much I don't like 10% as my odds!:o
"Some people follow their dreams, others hunt them down and beat them mercilessly into submission."

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If you compare more than two transportation modes, things get really weird. I was shocked when I first learned that walking is hundreds of times more deadly than driving, in terms of deaths per distance.

If this was adjusted for deaths-per-time-traveling, I'm sure it would look a lot different. Someone already mentioned this as a potentially valuable comparison adjustment for jumping vs. driving.



There are many posts of this variety, and each of them tells a different story... yeah, you can measure risk "per mile" "per minute" "per event" "per person" "per enjoyment" whatever.... my method was what made sense to me. In a given year, given the amount driving I do, and given the amount of skydiving I do, how does it stack up? saying 40,000 people died in car accidents and 40 people in skydiving accidents last year has no more meaning than saying that in 1 hour of driving you're a whole hell of a lot safer than 1 hour of freefall. Saying that on average you've exposed yourself to a greater amount of potential risk over the course of a year, while not perfect, is at least reasonable. If you don't accept that logic, fine, it don't bother my ass. If you think you have a better comparison, by all means say so. So far I haven't seen one.

To all those who commented about the assumption of a normal distribution of data, yeah you're right... that's probably not correct... maybe poisson, or einstein, or rush limbaugh came up with a more accurate distribution for skydiving, who knows. A degree in mechanical engineering taught me enough to know a normal distribution almost certainly does not apply, but not enough to know what most of those other ones mean, or if they are likley to apply. But you're really missing the point. The point is that the stats show a hypothetical "average" skydivers amount of risk. It's a good place to start, and if you analyze yourself and those around you (honestly, of course), you ought to be able to place yourself on one side of the average or the other... perhaps WAY on one side or the other. If you don't like those odds, you can change them. If you're happy with them, rock on(I am, or I wouldn't be doing what I do).



You could present it in terms of reduction in life expectancy. Some years back I calculated that the average loss in life expectancy for a 20 year old doing 100 jumps a year, every year, would be approx. 2 years. This compares with a 20 year old smoking a pack a day, which takes, on average, 6 years off your life expectancy.
...

The only sure way to survive a canopy collision is not to have one.

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You could present it in terms of reduction in life expectancy. Some years back I calculated that the average loss in life expectancy for a 20 year old doing 100 jumps a year, every year, would be approx. 2 years. This compares with a 20 year old smoking a pack a day, which takes, on average, 6 years off your life expectancy.




Wow, I like that one. "Skydiving: Less dangerous than smoking, much more rewarding"

Now what do I tell my motorcycle friends? :S
Good judgement comes from experience, and most of that comes from bad judgement.

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You could present it in terms of reduction in life expectancy. Some years back I calculated that the average loss in life expectancy for a 20 year old doing 100 jumps a year, every year, would be approx. 2 years. This compares with a 20 year old smoking a pack a day, which takes, on average, 6 years off your life expectancy.




Wow, I like that one. "Skydiving: Less dangerous than smoking, much more rewarding"

Now what do I tell my motorcycle friends? :S



Well, averages don't tell the whole story. Smoking takes a few years off the end of the life for a lot of people. Skydiving takes a whole lot of years from a small number of participants.
...

The only sure way to survive a canopy collision is not to have one.

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"It's true that if you've done 10,000 jumps successfully, your 10,001st is no more or less dangerous than the 1,000th. "

This isn't really true. Surely the 9,000 jumps worth of experience since your 1,000th would mitigate your risk somewhat.



Not for a double total...

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"It's true that if you've done 10,000 jumps successfully, your 10,001st is no more or less dangerous than the 1,000th. "

This isn't really true. Surely the 9,000 jumps worth of experience since your 1,000th would mitigate your risk somewhat.



Not for a double total...



Which are exceedingly rare.

Pilot error is responsible for 92% of skydiving fatalities. I worry a lot more about personality, training, and currency than equipment problems.

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- approximately 40% of driving fatalities involved alcohol levels of 0.08 BAL or more. I think it's fair to say that a higher percentage of drivers are drunk than skydivers, giving driving an even greater edge over skydiving, assuming you're sober.
Unless you're driving from LA to NYC to do a tandem;).




So wouldn't it be more accurate for this particular comparison then to figure in the percentage of HUNG OVER drivers that died???

cp

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i'm bored, so i will throw this in there.... htose who say driving is way safer... Any of you been through the "Orange Crush" during rush hour? .. or LA for that matter.. hahahaha. .. not THAT is dangerous.. not to mention accidently driving through compton
CLICK HERE! new blog posted 9/21/08
CSA #720

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Hypothetical discussions about the relative safety and/or danger of skydiving always annoys me and fascinates me at the same time. One the one hand, who cares whether it's safer that driving? Skydivers aren't dropping like flies, so it's obviously not like Russian roulette. Then again, it's really interesting to think about the ways in which we assess danger and acceptable risks.

Anyhoo...that was mostly me just thinking aloud. Moving on...:)

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Plus, how many people actually do a safety check on thier cars everytime they drive, like we do on skydiving rigs, scuba gear, and flying trike.

Somewhere between "on" and "start" on the ignition key, your car has a "lamp test" position where all the little warning lights come on. This tells you if the "brake" warning light is burned out. After you start the engine, if the brake warning light is on or comes on, there's something wrong with your brakes. It's still up to you to look at and care about the light, but it's at least one safety check that is, in a sense, done for you. OK, there are many other things on your car that could fail and hurt you and that don't (yet?) have sensors and warning lights, but the brakes are a common important one.

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And, these systems have back up...I dont think cars have a "reserve brake system." Although semi tractors do have a somewhat failsafe brake system if air presure is lost.



Cars built before about the late 1960s that had hydraulic brakes often had a "single circuit" hydraulic system. If you got a leak anywhere in the system, you had no main brakes at all and had to use the emergency brake/hand brake/parking brake. Cars built since then have a "dual circuit" hydraulic system; if you get a leak in the system, at least half of the system usually still works. Even then, they still come with an emergency brake/hand brake/parking brake. Recent car manuals have quit calling it the "emergency" brake, but it _will_ slow you down some if you have nothing else. (Try it sometime in an empty, dry, and flat parking lot.)

To get somewhat back on topic, I had this discussion with someone before I started to jump. His point was that you couldn't really "test" a parachute before you used it to make sure it was OK. He also gave the example of car brakes, pointing out that the way most cars are parked, you can't just start the engine, shift into gear, and accelerate up to highway speeds. First, you have to maneuver at low speeds to get out of the parking spot, and somewhere in this process you'll step on the brakes. If the brakes are not working correctly, it's very likely you'll notice it yet still be able to stop the car safely, so you can investigate the problem or use a different car. I agreed that you couldn't really "test" a parachute in that way, which is the reason for the inspect-canopy/pack/inspect-packed-rig for the main and the rigger inspection/pack for the reserve.

Eule
PLF does not stand for Please Land on Face.

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Somewhere between "on" and "start" on the ignition key, your car has a "lamp test" position where all the little warning lights come on. This tells you if the "brake" warning light is burned out. After you start the engine, if the brake warning light is on or comes on, there's something wrong with your brakes.



The "brake warning" lamp is activated by either the ABS computer throwing a code, or a float switch in the fluid res. on the master cylinder. It doesn't tell you that your brakes are working, or if you brake line is about to blow a hole.

Unless you crawl under the car each day you don't give 1/10 of the inspection you give to your personal rig.
"The restraining order says you're only allowed to touch me in freefall"
=P

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Unless you crawl under the car each day you don't give 1/10 of the inspection you give to your personal rig.



But what components of your car, upon failing, will cause as much danger as a failed rig? As long as the wheels, suspension, and brakes work, you're fine as far as I can see. Pull off the road and stop. I've had engines seize up on me and it was much less stressfull than having parachutes stop working on you. :D
www.WingsuitPhotos.com

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I've thought about this on and off too. There are several different replies in this thread already, but here is my take:

When I got involved in skydiving in 1973, I was told that if I kept at it, I would know someone who went in. Sure enough, someone did that same year. I have seen that same comment posted by people who have just started jumping within the last year or two, that someone told them they would know someone who went in.

Well, over the next 7 years, I knew 5 people who went in and in the remaining time until now, the number is in the 60s or 70s (I don't really want to know).

In all that time, I have always known at least as many drivers as skydivers (actually a ton more).

To this day (I am now 53), I have never known anyone killed in an auto accident.

So, to those participating in this thread and have more than say 3 years of active jumping behind them I ask "how many fatalities due to jumping vs. how many due to driving of people you have known?"

Not very statistical maybe, but I bet most will know no one killed driving and at least 1 killed jumping. It is dangerous... my method certainly does not compare overal rates of jumping vs. driving, but to me it's a fairer comparison to include all the skydivers I know vs. all the drivers I know.

-----------------------
Roger "Ramjet" Clark
FB# 271, SCR 3245, SCS 1519

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Interesting perspective.

But my first reaction is that I'm 28 and been skydiving for 2 years. I've not yet personally known anyone who died skydiving, but I have personally known 3 people who died driving. I guess that's why most people will take a statistical approach to defining activities as "dangerous"; individual experiences will vary.

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Interesting perspective.

But my first reaction is that I'm 28 and been skydiving for 2 years. I've not yet personally known anyone who died skydiving, but I have personally known 3 people who died driving. I guess that's why most people will take a statistical approach to defining activities as "dangerous"; individual experiences will vary.



Well, Nerd, your exposure to skydiving is 1/14th of your exposure to driving.

I've been around 61 years and have known 3 driving fatalities. I've been skydiving 10 years and have known 9 skydiving fatalities. So I guess my experience mirrors Roger's.
...

The only sure way to survive a canopy collision is not to have one.

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>but I have personally known 3 people who died driving.

I know one person who died driving. I know lot of people who have died skydiving/flying jump planes. The ones that come to mind first:

Harry the pilot
John O
Diego
Chris Martin
Taz
Shannon
Will
Shannon

I didn't jump at Perris before 1992 or I would have known 16 more.

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>That individual experiences ARE more relevant than statistical
>approaches to defining an activity as dangerous?

Well, if direct personal experiences really do have the most influence, then whuffos should think skydiving is perfectly safe - after all, most whuffos don't know _anyone_ personally who has died skydiving!

But clearly that's not true, so from a whuffo standpoint, something else is going on.

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