Half of Dead Divers on Their First 20 dives

[Geekhybrid]

Bubbletrubble: Thanks for your reply. To clarify, I wouldn't suggest that a newly minted OW diver's sixth dive is a the first dive of a rescue course. The requirement for PADi Rescue Diver is currently 20 dives, perhaps that's enough to allow some divers to begin to address some of the things you mention, perhaps it isn't. I do know AOW divers that still struggle with some basic buoyancy control and focus issues. So AOW isn't necessarily the fix to that. I suppose my argument really is that AOW need not be a requirement for Rescue, and to some people it might be a disincentive to taking a very important and beneficial course that I'd recommend to all divers, regardless of your long term diving intentions.

Boulderjohn: Thanks for the empathy! I did something similar to what you describe with I turned off my tank, except there was enough residual air in the system to add that puff of air to my bcd. Lesson learned.

And I no longer wear a snorkel. It's just another "point of failure" and drag.

I'm not suggesting I've now experienced and recognize all the common errors. Hence, "i've begun to understand..." in my post. I'm sure I have more embarrassment to come, but hopefully nothing any more life threatening that the gentle errors I've made to date

Jim Lapemta: your description of awareness is exactly the kind of thing I took away from my rescue Class. Before when I did a buddy check I thought of it more as a check that all was operational with my buddy. Now, after having to inflate a bcd, drop weights, remove gear in water for an unresponsive diver, etc. I look at buddy checks and awareness of other diver's gear differently.



Anyway, just a perspective for what its worth from a diver closer to the OP's possible 50%.

 

[2 Big 2 Fail]

There's just no practical way to get useful numbers regarding experience versus accidents. No one can say how many people can be described as "divers with less than 20 dives." Is someone who went through OW for their vacation and made a couple of dives on the trip and nothing for years and likely won't ever again to be counted as a diver in that class? They are, then, the safest of all, a "diver with less than 20 dives" who has zero chance of an accident. If the question is what class of divers have an untoward number of accidents and what might you do about it, you can't know anything unless you know both the number of accidents and how many people there are in the class. And in this case, you can't define the class in any usable way.

I would guess that if it's all those ever certified who have less than 20 dives, it's a really large class, probably by far the largest experience class. So what does a greater or lesser number of accidents in that class mean? Nothing, really, because the class isn't well defined. If I say it is indeed everyone certified with less than 20, then even a large number of accidents is a very small statistical incidence. I can change that incidence just by redefining the class. Maybe I could say it depends on how often they dive or how long it was since their last dive. But that doesn't help much, because you obviously have to keep diving to become an accident statistic.

Simple numbers of this sort just don't tell you anything. Statistical analysis can be useful. But it's unlikely that useful statistical analysis will be produced by the casual observer without sophisticated knowledge. And even with a solid grounding in statistics, if you're not asking the right questions, you're not getting useful answers. In a situation like this where you're trying to discover any significant factors so you can address them, you can't begin counting according to some arbitrary criteria like experience. If you do that, you've violated first principles by deciding without any evidence that experience is a factor. But if you observe enough different potential factors and happen to include the actual ones that matter, you can make useful predictions. The data reveals what factors matter. And very often, it turns out that the factors that matter are not those you would have guessed and not even those where you can see why they operate. If your goal is to discover significant factors, it's not an easy exercise. The list of things you're counting becomes very large, if you want to have a reasonable expectation of finding the right factors. It doesn't matter whether you happen to think something is a factor or not. The numbers will tell you if it is.

Collections of diving accident data that I've heard of are aimed at physical causes, triggers, and such, not prediction. It's like the difference between understanding the nature of automobile accidents and predicting them. Auto accident factors can be discovered, because the formal reporting is structured and rigorous, and even if some factors aren't reported directly, such things as driver experience can be generated from information in the reports, if a statistical investigator is interested. Even the color of the vehicle is reported, and if it happens to be a factor, the analysis will reveal its significance. And there's a nice repository for all those uniform reports. We don't have that kind of data for diving accidents. It would be an enormous job to try to collect the potential factors for a large number of diving accidents.

That leaves us with what we know of the nature of accidents, for which DAN collection is useful, and logical assumptions that new divers need practice and information, and old divers need practice and information.