Is anecdotal evidence dangerous?

[Cacia]

There are some great threads on this

I use anecdotal evidence like a tap on the shoulder....a clue for direction

 

[Teamcasa]

No, the problem is statistical sample size. Anecdotal evidence may be completely objective and verifiable, but it's a single datum, or, at best, a few data points. You can't demonstrate a correlation, let alone causation, for n = 1. You can't establish a reliable principle with a single observation, because you haven't established that it's repeatable.

Anecdotal evidence is not completely without value. A single datum is sufficient to rebut a blanket generalization - any statement involving the terms "always" or "never" can be disproved with a single verifiable counter-example. Of course, when dealing with the dynamics of human performance, as most dive safety/training questions do, it's very probable that the generalization was ridiculous to begin with, and thus no one who cares about valid proofs took it seriously anyway.

I concur. It is always a straight line between any two points.

 

[Cacia]

I have seen a lot of scientists, okay, medical doctors, completely miss the boat, becuase they were so in love with empirical evidence only. And then the question becomes, what is the statistical probablity that this is another random event?

(IMV)

 

[Nemrod]

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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Scuba is full of antedotal sayings and psuedo science. Just the other day there was a thread on shallow DCS and claims that you can get hit in four, (4), FOUR feet of water---lol. There is no science for that claim, just opinion tainted by legal necessity and PC BS. The Navy Tables that many of us still dive by used a 60FPM ascent and did not require a safety stop. I don't think using those tables is antedotal even if they don't agree with whatever might be in fashion at the moment.


For example, DIR is full of antedotal evidence, like, my team and I were blah, blah and I deployed my long hose and saved the day and we would have all died otherwise. OK, such examples as that we read over and over are antedotal. MOFH, antedotal, snorkel, antedotal, ascent rates, antedotal, safety stops, antedotal, Jetfins, antedotal, big knife vs little knife, antedotal, black skirted mask vs clear mask, antedotal, this tank vs that tank, antedotal, spg, vs wireless, antedotal, pony bottles vs small doubles, antedotal, solo vs buddy vs team, antedotal, sharks never bite, antedotal, sharks eat divers, antedotal. It is all antedotes and opinions. Yes, I agree with you, science is better than opinion and antedotes, the truth is out there if you can find it and failing the truth, logic will have to suffice.N

 

[JeffG]

For example, DIR is full of antedotal evidence

True. Mainly because the sample group is so small that it would be almost impossible to get a statistically sound result.

Makes for good debating though.

 

[Teamcasa]

True. Mainly because the sample group is so small that it would be almost impossible to get a statistically sound result.

Makes for good debating though.

Anecdotal evidence presented as fact is nothing more than an opinion based on a little actual experience. Separating the two is the basis for a good debate.

 

[Cacia]

DIR is full of antedotal evidence, like, my team and I were blah, blah and I deployed my long hose and saved the day and we would have all died otherwise.

lol...sorry...too great

My version: I dived by myself and saved myself a lot of grief.

hey...those LA death stats cited *buddy issues* as 10%....

 

[JeffG]

Separating the two is the basis for a good debate.

Actually, it is usually two sides, each with their own Anecdotal evidence and where no true "facts" exist. Only opinion and maybe some "thought experiments" to go along with the Anecdotal evidence..

 

[Cacia]

Let's suppose a diver commutes in a car and gets sick at depth on a 100 ft Ice Dive.

Then the next month, it happens again to someone else who made a commute to a dive, in the same ratty car.

If you are resistant to anecdotal evidence, you will see them as two isolated random events.

Otherwise, you will be calling the guy to check his exhaust system, or looking for rusted out hole in the floor, etc.

I could argue that anecdotal evidence is very useful, and that we use it more often than we even realize.

 

[Thalassamania]

Is anecdotal evidence dangerous?

Only when it's wrong.