Do Dive computer get you bent more than tables?

[blacknet]

Hello,

After reading over this issue of Dan’s magazine on accident stats I couldn't help but notice some rather interesting data. This is the section in question.

Dive computer uses continued to increase over previous years, with 73% of the injured divers reporting using them. 20% used dive tables, and 7% reported following a guide or dive instructor, using neither computer nor tables

From this data it SEEMS to me that use of computer usage will be more liable to get you bent over tables. Even lower odds if you are in a group dive and following an instructor/DM and NOT using either tables or computers.

In conclusion is it time to start calling dive computers bend-O-matics?

Ed

[large_diver]

Ed,

I think it would be premature to blame computers on DCS incidents based on these sparse statistics.

It could be that these statistics are representative of the entire diving population (e.g., that 73% of ALL divers use computers).

Regardless, these statistics tell us nothing about the main reasons behind the DCS incidents...other than that they happened and that some of the people were using computers.

-LD

[Green_Manelishi]

Statistically speaking, if there is no increase in the number of
divers being bent, but there is an increase in the number of
'puters being used then it would *appear* to support the claim
that 'puters get you bent. This is a perfect example of the ability
of statistics to prove almost any point, valid or otherwise.

I would say that MIS-use of 'puters will get you bent. Of course
the MIS-use of tables will get you bent.

[roakey]

In a quality control class Edward Demming showed us the above headline, published by a major newspaper, to illustrate most people’s complete lack of knowledge in terms of statistics.

You can gather NO useful information from just the numbers you quoted unless the percentages of divers using computers, tables and following DMs are known.

If, for instance, 90% of divers are using computers, 2% are using tables and 8% are following DMs, resulting in DCS incidence rates of 73%, 20% and 7% respectively, then we should start calling the tables bend-O-matics, not the computers.

To add even more confusion, probably most divers using tables are deep technical divers, so the data gathered from that class of divers cannot be drawn upon for any useful information applicable to recreational divers.

My guess that the number of divers using computers (in the pool of divers who, if they encounter DCS, DAN will see the information) exceeds even the 90% I used in the example above, meaning that computers are really, really safe.

Does DAN go on to give a breakdown on the percentage of divers using computers, tables and following DMs, or is this just more DAN fuzzy statistics that seems to be plaguing the organization lately?

Roak

[large_diver]

Statistics aside, as GM said -- it is mis-use of computers that may be the culprit......thus poor training is probably the real reason for increasing DCS incidents....

[Stone]

I agree with large_diver that the statistics aren't enough to say there is a correlation between computer usage and getting bent; however, "Being paranoid doesn't mean there's not really someone out to get you."

Since computers are touted as a means to maximize your bottom time, I would not be suprised to find out that computer divers spend more time right at the NDL than a table diver.

Regardless, "Computers don't bend divers, divers bend divers"
(Sentiment borrowed from the NRA)

[large_diver]

Stone -- well put

[rcohn]

You also need to know more about diving habits. As Roakey pointed out deep technical divers use tables but they are a rather small group and I'm not sure how DAN includes them (trimix, rebreathers, etc.) in the sport diving statistics.

The other group of table users is much larger, the new and occasional divers with minimal gear of their own. These divers may generally stick to shallower safer dives and burn air faster shortening the bottom times. If so they would be less likely to be bent using either tables or computers.

Most computer users (a very large group) fall in between these extremes. They may dive deeper and more frequently than the newbies/occasional group, have a tendency to do more intensive multiday diving (liveaboards etc.), and are capable of longer bottom times, which would lead to more cases of DCS.

Without evaluating all these factors and knowing how many divers use computers, how many divers use tables, and how many and what type of dives each group does in a year, you can't conclude anything about the safety of computers relative to tables. Although I've seen "experts" try to use these statistics to support their preconceived biases.

Ralph

[tombiowami]

I had the same reaction with the DAN info, but with the seemingly high percentage of dead divers with coronary/heart/artery disease. It is really hard to determine what is what with the stats presented.

Tommy

[Lost Yooper]

I agree with all of the responses. The majority of DCS cases are occuring with very new divers. Herein, lies the bulk of the problem followed by divers having obvious and not so obvious preconditions that would invite DCS, and utilizing poor deco procedures (as well as predive and post dive activities) as taught (or ignored) by agencies and used by divers.

The problem I see with computers (and even some tables) is the fact they can't account for individual preconditions (that the user may or may not even know about) that could facilitate DCS and then incorporate less than ideal decompression alogorithms. I think computers are partly to blame (a small part). A lot of the blame falls on the diving industry as a whole, and yet a piece of the pie must fall on some of the divers getting bent, IMO.

Later.

Mike