Is it worth it?

[PfcAJ]

I don't have a figure on how many dives were done in the entire. world. Sry. All I can show is that new divers are more likely to die than divers who have been certified longer.

 

[T.C.]

I don't have a figure on how many dives were done in the entire. world. Sry. All I can show is that new divers are more likely to die than divers who have been certified longer.

Well, unlike you, I will withhold judgment until I can read the full report. Were these the only three categories? What about divers between 1 year and 10? Do we just ignore them in the statistics?

These divers probably account for the vast majority of divers, but if there are more new divers than old, the statistics will skew. Given that many people start diving, then give it up within a year, there is a very good chance that divers with 1 year or less are equal or greater in number than 10+ year divers.

A set of numbers with no background is essentially worthless. You can make them say whatever you want. Remember; 90% of statistics are false.

 

[Omisson]

I just took a gander at the 2009 Annual Diving Report from DAN. Page 64 has a graph of # of years certified and %of deaths reported in 1yr.

The curve looks bimodal at first till you consider the total population, how many divers would fit into each category, and how many years each category spans.

In the "certified less than 1yr" and "1yr" categories the total is 30ish % divers died fell into those two groups. For the greater than 10yrs category it has 40%. That seems to suggest to me that newer divers are more likely to experience a fatal accident. <1 and 1yr is a very defined group compared to ALL divers certified for greater than 10yrs.

n=48 for that particular year.

Most fatal accidents were also pretty shallow and off boats. Naturally, most dives are probably really shallow and off boats, but it's at least relevant to the discussion here.

How do you reach the conclusion that newer divers are more likely to experience a fatal accident?

First the raw data says that divers with 10+ years are the greater number of incidents

AND

second the dive population data indicates that there are more people certified in the midrange ( as opposed to under 2 years or over 10 or more years) today than any other category.

AND

The DAN study concludes the average age of divers and length of time diving is on the rise and the highest it's ever been but that 55% of divers are diving under 10 years 45% over (30% under 2 yrs). So on straight percentage:

40% over 10 years
60% under 10
(35% under 2 yrs)

It seems to me it is evenly distributed amongst the groups, statistically.

Maybe you have other numbers than the 09 report?

 

[TMHeimer]

I believe I've heard more than once that new divers lead in accidents/deaths, but 2nd place goes to very experienced ones including instructors, etc.-- because they become too complacent. Don't know if that has anything to do with this discussion, but...

T.C., I certainly agree about statistics often meaning little. But on your point about post-OW courses creating dependent divers maybe not. I would GUESS that the sheep being lead around always by DMs (while on vacation, etc.) probably has little to do with courses. I've heard a lot of these people dive very little locally if at all. I would think that someone taking courses soon after OW also is doing a lot of independent diving (as was the case with myself). Some of these people also would be trying the "zero to hero" pro route I guess.

 

[PfcAJ]

Well, unlike you, I will withhold judgment until I can read the full report. Were these the only three categories? What about divers between 1 year and 10? Do we just ignore them in the statistics?

These divers probably account for the vast majority of divers, but if there are more new divers than old, the statistics will skew. Given that many people start diving, then give it up within a year, there is a very good chance that divers with 1 year or less are equal or greater in number than 10+ year divers.

A set of numbers with no background is essentially worthless. You can make them say whatever you want. Remember; 90% of statistics are false.

Heh. Here we go again, trying to say what I'm thinking and what judgement I've passed. I read the report...unlike you.

I gave you the sample size (n=48). They used % vs a number of divers BECAUSE there might be more (or less) of a certain group. I attempted to articulate that there were multiple groups (the middle groupings aren't that interesting imo). I highlighted the fact that DANs groupings can lead to false conclusions (bimodal appearance) as 0-1yr is a much smaller time frame than >10yrs. If you were to redistribute the ">10" years into 2yr groupings, I'd make a pretty strong bet that there would be a strong negative trend line since a full 30% of the reported fatalities were of divers certified for 1year or less. Interestingly enough, reports from prior years show a similar pattern. I even told you the year, compiler, page, and NAME of the report so you could look at the figures yourself.

Statistics aren't false. People's interpretation of them can be false because they don't understand statistics. Stats was a decent chunk of my undergrad and I use simple stats semi-frequently in my day job.

 

[T.C.]

T.C., I certainly agree about statistics often meaning little. But on your point about post-OW courses creating dependent divers maybe not. I would GUESS that the sheep being lead around always by DMs (while on vacation, etc.) probably has little to do with courses.

That's not what I'm saying. What I'm saying is that taking a course just to be supervised, like the poster I was responding to said, develops a habit of relying on on the 'supervisor' to do the dive planning and decisions, which leads to dependent divers.

 

[PfcAJ]

How do you reach the conclusion that newer divers are more likely to experience a fatal accident?

First the raw data says that divers with 10+ years are the greater number of incidents

AND

second the dive population data indicates that there are more people certified in the midrange ( as opposed to under 2 years or over 10 or more years) today than any other category.

AND

The DAN study concludes the average age of divers and length of time diving is on the rise and the highest it's ever been but that 55% of divers are diving under 10 years 45% over (30% under 2 yrs). So on straight percentage:

40% over 10 years
60% under 10
(35% under 2 yrs)

It seems to me it is evenly distributed amongst the groups, statistically.

Maybe you have other numbers than the 09 report?

Happy to explain.

>10 years is really open ended and non specific. Think of how ridiculous their graph would have to be if they had a diver at 11 years, 2 at 15, then 1 who had been certified for 30years. What are they going to do? Have 20 "0"s? Silly from a presentation standpoint, so they consolidated.

Lets take a look at your 3rd point for a moment. 35% under two years. 2. Thats it. The next group (under 10, more than 1) is 5 times that. So a bit less than double the % roughly (35% to 60%), but five times the number of years we're looking at. Its not apples to apples.

Back to the 2nd point, if there are more divers certified in the 'mid range' as defined as greater than 2yrs but less than 10yrs, why is that segment so under represented? If all groups were equally likely to experience a fatal accident, we'd see a higher % than 40%. Heck, looking at the divers with <1 and 1 is nearly that value alone, and its a WAY smaller time period.

Its a little late, so I could be off a little here, but I think its fairly clear cut that year for year, the newer a diver is the more likely they are to experience a fatal accident. There's probably some sort of upward trend eventually (complacency factor), but our sample size is just too small to show it. We don't have the data to draw a meaningful conclusion about that.

I hope what I wrote makes sense, and I'll be happy to clarify anything if need be.

 

[T.C.]

Heh. Here we go again, trying to say what I'm thinking and what judgement I've passed. I read the report...unlike you.

I haven't read it because my computer is being stupid tonight. I will read it tomorrow at work, and debuke your conclusion further; however, Omission did a good job of pointing out that these groups are roughly equal, and not showing the conclusion you believe.

Stats was a decent chunk of my undergrad and I use simple stats semi-frequently in my day job.

Then you may want to relook at these statistics. If Omission is right, it'd make me wonder about the quality of your work.

There are alot more variables involved to take these few numbers and state: New Divers dive more than old.

 

[PfcAJ]

I haven't read it because my computer is being stupid tonight. I will read it tomorrow at work, and debuke your conclusion further; however, Omission did a good job of pointing out that these groups are roughly equal, and not showing the conclusion you believe.


Then you may want to relook at these statistics. If Omission is right, it'd make me wonder about the quality of your work.

There are alot more variables involved to take these few numbers and state: New Divers dive more than old.

SO even if the data supports what I said, you're going to debunk it.

OKAY....

 

[Redshift]

Judging from the way a lot of lot divers behave on a dive boat (spread their gear all over the place, block walkways with mounds of gear, take up all the storage space, etc). I would say that a lot of people NEED to take a boat diving course.

Those are not divers needing a boat diving course, those are people needing manners.