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Bob_Church

Parchustist' equipment reports for fatalities

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I think maybe it's time for USPA to revamp the fatalities reports as far as the gear goes. I think it should start including things like wing suit type. I'd also like to see helmet and goggle types. I realize that's a lot of info to collect but it would be worth if if we could detect for instance a combination of a particular helmet and goggles that keeps showing up in canopy collisions.

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VTmotoMike08

All that would do would be to tell you the most popular type of helmet and googles.



Why? If some combinations of gear is causing too much loss of visual or audible cues it would be nice to know. Do you feel the same way about the listing of canopy and rig?

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councilman24

It's hard to get complete fatality reports now. Or at least it was for the 20 years I was a S&TA. Getting that detail would be difficult for little benefit. Remember USPA has not right to any of the information.



Getting someone to gather the information can be difficult, but once someone is filling out the form this is just a couple more boxes to fill in. As to benefit, how can we know if it's helpful or not if we don't gather the information? I know that one reason for collisions is just people who aren't watching, I jump with one guy that you just know not to get in front of. Unless you're wearing a jumpsuit with a design that looks like pea gravel he'll never see you. But I've also seen near collisions and videos of actual canopy collisions that seem to me can only be caused by blind spots. Or maybe not.
It would be nice to know.

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I think the point is that this data would not be statistically significant without being normalised to the prevalence of each piece of equipment on all jumps.

Just because every incident involves a G3 does not tell you that the G3 is causal. It tells you simply that it’s highly likely that a person having an accident is wearing a G3, simply because it’s highly likely that a person leaving an aircraft at 12,000ft is wearing a G3.

Unless you can say that the G3 accounts for 50% of all jumps but 70% of all incidents, the latter number doesn’t give you any useful information.

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benlangfeld

I think the point is that this data would not be statistically significant without being normalised to the prevalence of each piece of equipment on all jumps.

Just because every incident involves a G3 does not tell you that the G3 is causal. It tells you simply that it’s highly likely that a person having an accident is wearing a G3, simply because it’s highly likely that a person leaving an aircraft at 12,000ft is wearing a G3.

Unless you can say that the G3 accounts for 50% of all jumps but 70% of all incidents, the latter number doesn’t give you any useful information.



Thank you! Someone that understands statistical analysis!

Also the n number would be impossibly small making the sample irrelevant.

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Anachronist

***I think the point is that this data would not be statistically significant without being normalised to the prevalence of each piece of equipment on all jumps.

Just because every incident involves a G3 does not tell you that the G3 is causal. It tells you simply that it’s highly likely that a person having an accident is wearing a G3, simply because it’s highly likely that a person leaving an aircraft at 12,000ft is wearing a G3.

Unless you can say that the G3 accounts for 50% of all jumps but 70% of all incidents, the latter number doesn’t give you any useful information.



Thank you! Someone that understands statistical analysis!

Also the n number would be impossibly small making the sample irrelevant.

And ham is saltier than turkey.

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JerryBaumchen

Hi Anachronist,

Quote

understands statistical analysis!



***the n number would be impossibly small making the sample irrelevant.



^^^^ These comments.

Jerry Baumchen

Is any of the gear information gathered after a fatality statistically significant? Should we just skip the whole thing?

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benlangfeld

It’s probably useful for better understanding of individual incidents. It’s not useful (indeed it’s possibly dangerous) for the purpose of spotting patterns.



And that's different from the information we gather now in what way? If we can't punch it into SPSS then just let it go?

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Hi Bob,

Quote

information gathered after a fatality statistically significant?



Not according to my Stats instructor ~49 yrs ago.

I doubt that it has changed over the years.

About 30 people die jumping in the USA each year. 30 is a VERY, VERY small sample to make any probable predictions.

Jerry Baumchen

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Bob_Church



Is any of the gear information gathered after a fatality statistically significant? Should we just skip the whole thing?



Not really.

In part, the sample size is very small. Not only the total number of incidents, but the number of gear related incidents is miniscule.*

In part, there's no baseline. We can say that (for example) a Vector H/C was involved in "X' accidents, and "Y" percentage of total accidents, but without knowing how many Vectors are in use, or the percentage of H/Cs that are Vectors, the X & Y are useless.

I don't think we should 'skip the whole thing', mainly because you never know what info is important.

But the sorts of things that statistical analysis reveals are usually already known from the accident investigation.

It's pretty rare that the cause of an incident, particularly gear related ones, isn't understood. While there have been a few things that were caused by faulty gear, every one that I can think of had a cause determined and a fix implemented before the number got high enough to show up in the stats.

* - If every incident, every malfunction that resulted in a cutaway was reported in full detail, then we might have enough data to draw conclusions, even without the baseline.
"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo

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Ok, so this comes down to yet another area of "don't ask don't tell" about skydiving equipment. Personally I feel that we should gather information then see what, if anything, it tells us. But I've noticed the growing opinion of best left unasked and unanswered. It's a matter of opinion I guess.

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No, I think you've misunderstood, or are taking it personally for some reason. The argument that's being presented is a purely mathematical one which states that anything that you might do with the data once gathered that you wouldn't have planned to do before gathering it would be an attractive un-scientific trap. "See what it tells us" sounds like code for "if X brand helmet shows up a lot, there MUST be something wrong with it", which would be lacking in rigour.

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Bob_Church

Ok, so this comes down to yet another area of "don't ask don't tell" about skydiving equipment. Personally I feel that we should gather information then see what, if anything, it tells us. But I've noticed the growing opinion of best left unasked and unanswered. It's a matter of opinion I guess.



No.

I don't see any real problem gathering as much info as possible, other than making the form longer by asking for more detailed info may result in fewer people willing to fill out the forms.

I just don't see any real benefit to it.
"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo

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benlangfeld

No, I think you've misunderstood, or are taking it personally for some reason. The argument that's being presented is a purely mathematical one which states that anything that you might do with the data once gathered that you wouldn't have planned to do before gathering it would be an attractive un-scientific trap. "See what it tells us" sounds like code for "if X brand helmet shows up a lot, there MUST be something wrong with it", which would be lacking in rigour.



Now you've added that I'm taking it personally. I don't know where that's coming from. Yes, I believe in gathering as much information about a fatality as possible. That's must my opinion.
Some people seem to think that gathering this information isn't a good idea. Ok. I disagree. I disagree a lot, but it's not like it's some kind of problem.

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wolfriverjoe

***Ok, so this comes down to yet another area of "don't ask don't tell" about skydiving equipment. Personally I feel that we should gather information then see what, if anything, it tells us. But I've noticed the growing opinion of best left unasked and unanswered. It's a matter of opinion I guess.



No.

I don't see any real problem gathering as much info as possible, other than making the form longer by asking for more detailed info may result in fewer people willing to fill out the forms.

I just don't see any real benefit to it.

I don't think we can know if information will have benefits or not unless we gather it.

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Well, the push-back you're getting is that any conclusion you might come to based on the aggregate data gathered would be highly likely to be false, and you're suggesting that there's some sort of cover-up going on. I think a majority of people in this thread have also said that the data might be useful, just not for patterns.

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Bob_Church

I don't think we can know if information will have benefits or not unless we gather it.



But that's just not how statistics works. The data being written in front of you doesn't change the rules about how you must analyze it in order to reach defensible conclusions.

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