Experience levels & diving deaths

[Rhone Man]

I recently finished reading Jablonski's Fundamentals of Better Diving and one statistic he quoted jumped out at me: nearly 60% of diving fatalities involved divers who had 20 or fewer career dives. He cites Elliott and Bennett, The Physiology and Medicine of Diving (4th ed. (1993), pages 238-252) as a source, so I took that statistic as gospel (although I have never checked the primary source).

However, by coincidence a little later on I was leafing through the DAN accident statistics for 2008, and they publish a table showing length of time diving (this table is subject to DAN's copyright) which strongly indicates the reverse is true:

Going back to 2007, the equivalent table shows a very similar pattern.

In the text, the report indicates that: "Fifty-six of the victims (75% of all cases) were known to be certified but information on the certification level was missing in half of these cases. The cases with known information included three student divers, six with open water certification, six with an advanced or specialty certification, six with technical certifications, and four instructors."

The report for 2007 was similar: "Seventy-one of the victims were known to be certified but information on the certification level was missing in half of the cases. The half with information included one student, nine with open water certification, 13 with an advanced or specialty certification and 22 with higher certification."

That very much seems to be at odds with the earlier statistic - we have moved from predominantly the rookies who were dying to predominantly veterans. Does anyone have any idea why? Can there have been that great a statistical shunt between 1993 and 2007/8?

 

[Peter Guy]

Rhone Man -- I certainly don't have a clue as to the answer but I wonder:

a. Are there a significantly higher percentage of "technical" divers now which would mean that the absolute numbers of deaths would increase?

b. If there are a significantly higher percentage of technical divers, would that lead to a greater number doing more "risky" dives, hence the higher number of deaths?

c. Despite what "some" might say, has the basic training/gear for the newbie gotten better and thus reducing the death rate for newbies which would then increase the percentage rate for "advanced" divers?

My guess would be that there is a substantial increase in advanced and/or technical divers which would lead to the higher death numbers of that group -- even if the death rate stayed the same or decreased.

 

[elan]

IMHO number of years in diving are not related to the experience level anyhow I would think the more correct indication of experience would be number of dives done per year supported by number of total dives or number of years related to the environment where the accident occurred. Otherwise it's just measuring and average body temperature in the hospital. This kind of statistics does not tell anything.

 

[ligersandtions]

I'm curious if the statistics actually do work with each other (for example, if the majority of the people who died in the >10 years diving had fewer than 20 career dives).

I also don't know how relevant I feel those statistics are. I would be more curious how many active divers were dying (and whether they were in open water or an overhead/deco environment) versus those who dive once a year or every other year.

 

[Rhone Man]

Just to flesh it out a bit more, I went back to 2006 and 2005. 2006 showed a big jump in the number of "rookie" deaths (tables below - copyright is DAN's), but 2005 went back to the pattern of 2007 and 2008 - deaths being more prevalent amongst the veterans.

 

[Rhone Man]

I wonder if it is simply that age overall is a more important indicator. Most diving deaths seem to occur with divers in their 50s (often as a result of existing medical conditions). How long they have been diving is less important than the fact that they are getting old, and exertion or stress is more likely to create a fatal scenario?

If that is right, then the switch in the statistics could simply be blamed on the baby boomers (why not, we blame them for everything else...).

 

[TSandM]

I've read before that there is a bimodal distribution. New divers tend to die from complications of buoyancy problems, or from panic; more experienced divers tend to die from pushing their limits or from complacency, often in the setting of more complicated and unforgiving dives. For example, the distribution of cave diving deaths is moving away from uncertified or incompletely trained divers and toward experienced people who fail to follow the basic safety rules.

But my first take on the "number of years diving" graph is that if you've been diving more than 10 years, you're older . . . and an awful lot of diving deaths get signed out as heart attacks.

 

[openmindOW]

I am by no means an expert on the questions at hand, but I have to agree with the suggestion made above that cardiac events account for some dive fatalities. I read DAN's annual report on dive incidents. (The 2008 edition is out now and can be ordered through DAN.) There seem to be a lot of fatalities with divers in their 50s and with divers who are described as obese.

 

[Ken Kurtis]

Good discussion and thread.

In my work with the LA County Corner as a forensic consultant, we've lately been compiling stats and trying to discern trends. Don't forget that with scuba diving though, it's a fairly small sample size to begin with and with very few deaths, one or two more (or less) in this category or that significantly skews the numbers.

I'll get to the numbers we have in a moment but a few things to consider:

1. There's no question that newer divers get into trouble through inexperience.
2. Experienced divers get into trouble either because they've become complacent over the years or . . . they stopped diving for a while and started again, effectively making them just like a newer diver but with an older cert card.
3. Undiagnosed underlying medical conditions, especially with divers over 50, seem to be playing a larger and larger role.
4. Don't hang you hat on cert level. I've got a guy who dives with me who has been diving for 40 years, has a couple of thousand dives, and has a basic card. If he died, he'd go under "basic".
5. Don't lose sight of the fact that sometimes things like cert level and number of dives and other things are based not necessarily on hard evidence but on best recollections of family members and they're sometimes just plain wrong.

Because the numbers we have in LA County are so relatively small, I took a look at the national stats based on the DAN published numbers for 2003-2005. (I'll amend this soon now that the 2006 numbers are available.) Remember that DAN's numbers reflect deaths in the US, and US citizens (and maybe Canadiens - I can't recall offhand) who die abroad. I complied DAN's numbers and came up with the following:

TOTAL DEATHS FOR THE 3-YEAR PERIOD: 266

AGE OF THE DEAD DIVER:
10-17 - 1 (>1%)
18-29 - 28 (11%)
30-39 - 37 (14%)
40-49 - 76 (29%)
50-59 - 93 (35%)
60-69 - 19 (7%)
70+ - 6 (2%)

KEN'S GENERAL CLASSIFICATION OF THE CAUSE OF DEATH:
Bad luck (i.e, run over by a boat) - 5%
Bad health (heart attack, etc.) - 25%
Bad diving (diver error) - 70%

OF THOSE WITH "BAD HEALTH" (63 OUT OF 266 - MEANING A MEDICAL COMPONENT CAUSED OR DIRECTLY CONTRIBUTED TO THE DEATH):
10-17 - 0 (0%)
18-29 - 2 (3%)
30-39 - 6 (10%)
40-49 - 19 (22%)
50-59 - 31 (49%)
60-69 - 9 (14%)
70+ - 1 (2%)

The numbers merit a lot more investigation and discussion. But part of what we see is that there's quite a strong argument for divers, esepcially those of us over 50, to have a REGULAR (perhaps annual??) medical checkup to clear oursevles to dive.

But also don't lose sight of what I think is the most glaring statistic and obvious lesson to learn here: 70% of the dead divers (186) made stupid mistakes (diving uncertified, untrained divers in caves, running out of air, etc.). If they'd simply used their heads and been a little smarter/dilligent, they'd still be alive.

Stupidity kills. If we can teach our divers to be smarter, we could IMMEDIATELY cut fatalties by 70%. That's a significant number (IMHO) and a valuable walk-away lesson.

- Ken

P.S. - If you're in the LA area and book speakers for your shop or club, I have this talk in a PowerPoint 45-60 minute version and am happy to come pontificiate to your group. Just give me a shout.

 

[ianr33]

My problem with those graphs is that the time spans for each bar are not the same.

>10 years of diving covers a lot of ground. Anyone in diving for the long haul might be a diver for 30 years. Divide the height of the >10 bar by 30 and it will be tiny.

Lets look at it another way. Just split the graph into 2 bars:
1)Less than one years experience and
2)More than one years experience.

the second bar will be much higher . Therefore "proving" that more experience makes you less safe.

IMHO it is very shoddy reporting/statistics and DAN should know better.