Is anecdotal evidence dangerous?

[Teamcasa]

I have read so many posts that use only anecdotal evidence to support a particular point of view. To me this is down right dangerous in some cases. When it comes to diving, I see this as very troubling. How many times have we all read “ I’ve been to 160’ fsw on air and did fine” or “I came up from 100’ and did not do a safety stop” or “I don’t get narcked at 120’ fsw”. This sends a message that if I did it, you should be fine so go ahead and try it! I am always dubious when the only evidence is anecdotal.

I believe in the premise that science trumps anecdotal evidence every time. This not to say some have in fact done some of these things but is it safe for anyone, no. So when someone presents a situation where the only evidence is anecdotal, do more research before trusting the information.


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[RICHinNC]

The problem with anecdotal evidence is that it is tainted by personal view and not supported by emperical evidence gathered in a scientific controlled environment.

What one person does and succeeds in is not necessarily good for another.

Bottom line....in many cases you just have to take things with a grain of salt....and that include the "real" info.

 

[TSandM]

Dave, I agree with you. It's one thing to discuss the merits of various brands of equipment, where anecdotal evidence may be the only thing available. It's another thing to do it with things like decompression strategies, oxygen toxicity, or narcosis.

This is one of the enormous values of the Rubicon Research Archive. There, you can search a large database of published scientific studies on a wide variety of diving, or diving-pertinent topics.

 

[Web Monkey]

I have read so many posts that use only anecdotal evidence to support a particular point of view. To me this is down right dangerous in some cases. When it comes to diving, I see this as very troubling. How many times have we all read “ I’ve been to 160’ fsw on air and did fine” or “I came up from 100’ and did not do a safety stop” or “I don’t get narcked at 120’ fsw”. This sends a message that if I did it, you should be fine so go ahead and try it! I am always dubious when the only evidence is anecdotal.

I know a guy who got drunk and drove home every night for decades (retired now) and lived.

That doesn't make it right or safe.

Just like the people who go into overhead environments "just a little" with no line and no training.

Terry

 

[fweber]

Dave,

With regard to your question or statement, "is it safe for anyone, no." The only approach to diving that would be "safe for anyone" or everyone, is to not dive in the first place. And, while scientific studies certainly have their place and the Rubicon Archive is a massive asset, it must be remembered that many of those studies have been performed on extremely fit military divers that don't compare with the average diver much less all divers. Furthermore, there are some very valuable contributions to diving that have, in their infancy, been based on purely anecdotal evidence. Richard Pyles deep stops would be one that comes to mind.

The dangerous thing is to take anything as fact without serious thought about it's ramifications.

 

[Guba]

Ow, I don't know. Anecdotal "evidence" seems to work just fine for me. Why, just the other day I had a fellow tell me that he'd been listenin' to dive stories all his life and....

Wait a minute--this is another acecdote, isn't it?

 

[dboddy]

I feel that it can be just as dangerous to assume that science will always keep you safe. There are plenty examples of highly skilled divers following scientific, conservative diving practices that still get bent without any obvious reason. Part of the scientific equation involves the use of subjects. Vary the subject...vary the results. Even our own bodys can be different from day to day and that will change how scientific principals apply.

The best approach, IMHO, is to learn your own limitations, slowely and at a safe pace. Strive to do more and to go further with the intent of learning your limitations and not for the reason of breaking records, meeting challenges or impressing others. Use the science as a guide and not a bible and let common sense prevail.

 

[ClayJar]

I've never been hurt by relying on anecdotal evidence...

The thing that annoys me is how confusing it was last time I looked at DAN's Project Dive Exploration. I'd really like to submit my profiles and reports, but the whole thing was so convoluted and confusing, I gave up and went home. (What has to be submitted when, how, to whom, and whahuzny?)

Someone want to suggest they streamline the process and then make a little online seminar "Getting Started with Project Dive Exploration"? It would certainly help collect more data to supplement the anecdotes.

 

[Teamcasa]

Dave, I agree with you. It's one thing to discuss the merits of various brands of equipment, where anecdotal evidence may be the only thing available. It's another thing to do it with things like decompression strategies, oxygen toxicity, or narcosis.

This is one of the enormous values of the Rubicon Research Archive. There, you can search a large database of published scientific studies on a wide variety of diving, or diving-pertinent topics.

Lynne makes a good point about when anecdotal evidence is all that is available we are forced to make a decision knowing the risks.

Where anecdotal evidence is nothing more than a testimonial, I tend to review it carefully. However, in some cases a testimonial works for me. Such as, does this harness fit well, is this camera easy to use or, I did not like the way that mask fit me or that (gear) feel apart after only a few dives.

When it come to real safety issues, I simply don’t trust anecdotal evidence.

 

[bleeb]

Another way to look at this is that an anecdote is like one data point. How much do you want to trust your life to a statistical sample of one? The advantage of the scientific studies (at least some of them) is that they consider a more useful number of cases. The "I've been to 160' on air" anecdote doesn't tell you whether it's one serious injury per hundred dives, which I suspect a significant fraction of divers would be concerned about, or whether it's one in ten thousand, which may be tolerable to most. That's one thing that's always bugged me (probably like the OP) about postings which argue 'but I did X and didn't die.'