Thursday, June 16, 2011

Radiation, Drug Testing, Critical Thinking, Analytical Reading and Probability

I've written extensively on the ridiculous nonsense that passes for news and how too many people in this day and age seem unable to filter through the crap and make a logical assessment of what they should and should not believe.

A traditional American song about nonsense.

Yesterday's article was a good example of junk that was being passed for "news". In "Metallic Tastes in Mouths Proves Nuclear Disaster in Japan! Or Does it?" I wrote:

Once again, Arnie Gundersen and a bunch of illogical panic stricken fools say something stupid about Fukushima and radiation. 

They are now saying that there is "anecdotal evidence" of people having a metallic taste in their mouths and, from this, they draw the wild conclusion that this means there is an uncontrollable nuclear chain reaction going on at Fukushima. This nonsense has no basis in science, reality, nor does it have any evidence backing it up. It is fantasy. I has no real meaning to anyone who actually has more than two brain cells functioning.

If you do a random search today on Google, you can find some people who have now "drank the poison" and, in their uncontrolled paranoia have begun to believe that they, too, have a metallic taste in their mouths.

This "anecdotal evidence" is pure idiocy. Anecdotal comes from the word, Anecdote. "Anecdote" in the Merriam Webster dictionary is defined as:

a usually short narrative of an interesting, amusing, or biographical incident.

"Anecdotal" is defined as:

: based on or consisting of reports or observations of usually unscientific observers <anecdotal evidence>
of, relating to, or being the depiction of a scene suggesting a story 

"Suggesting a story"? Indeed.

Once again, this question comes down to a problem of critical reading and analytical thinking abilities. In the above case, concerning that clown Arnie Gundersen, I find it astounding that anyone, for even a split second, would consider this "metallic taste" and "anecdotal evidence" nonsense as proof of a problem (other than hypochondria). I also can't believe that this guy opens his mouth up and says this stupid stuff and then doesn't want to crawl back into a hole in embarrassment.

These problems repeatedly come down to a basic understanding of logic which lies in an even more basic understanding of math and probabilities. I'm not sure what the percentage probability of "Anecdotal" is, but I would put it at about 0%.

Anyone care to debate that point?

Here's a good question for dear reader to consider. It is from The Power of Logical Thinking - Easy Lessons in the Art of Reasoning … and Hard Facts About Its Absence in Our Lives by Marilyn Vos Savant:

"A particularly and important question today is that of testing for drugs. Suppose it is assumed that about 5 percent of the general population uses drugs. You employ a test that is 95 percent accurate, which we'll say means that if the individual is a user, the test will be positive 95% of the time, and if the individual is a nonuser, the test will be negative 95% of the time. A person is selected at random and given the test. It's positive. What does the result suggest? Would you conclude that the individual is highly likely to be a drug user?"

I think that most people would say that the odds of this randomly selected person, who tested positive for drugs, are 95% correct. This is a very common misunderstanding. The tests show that this person has a 95% chance of being a drug user. But the result of a one-time random test is way off from the actual odds of this person being a drug abuser. The chances that this person is a drug abuser are nowhere near 95%. Understanding this should make people who consider the results of drug testing great pause.

The correct answer to this test, once again, lies in logic and math. 

I hope some reader will be able to solve this puzzle. The correct answer is actually quite simple and can be done with a pencil and piece of paper or with common sense. Of course, like the metallic taste in mouths, the common sense method is much better and more fun.

In a weaselly attempt to get dear reader to come back to this blog I will post the actual percentage of this person being a drug abuser with a simple explanation tomorrow. 

I wonder what my odds are of etting you to come back tomorrow? 50/50?


James said...

Fifty-fifty indeed!

Perform this test on one hundred people. 95 of them will be non-drug users, but 5% of them will get false positives on the test = 4.75 people.

Five people will be drug users and will get true positives 95% of the time = 4.75 people.

So out of the 9-10 people out of 100 that this test will flag as positive for drugs, only half of them will actually be drug users.

That right?

Anonymous said...

I despise drug testing. Some of the safest and best workers I had the pleasure of working around wouldn't pass such a test.

But more importantly, a hand eye coordination test - and simply talking to People - is a better method of determining who should be on the clock and who shouldn't. IMHO.

Some of the most dangerous People and some of the stupidest People ever pass drug tests and I wouldn't want to be anywhere near them in dangerous circumstances.

- Clark

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