Tuesday, December 23, 2008

The Texas Sharpshooter

Someone looking at the graph in my last posting asked what the increase in aggression around age 45 might mean.

It may represent a sampling problem. There may be an outlier, a single individual who is very aggressive pushing up the numbers. Or there may be a disproportionate number of 45 year-olds in the group.

But let's say we rule out a sampling problem. Then we might have fun speculating about why humans seem to become more aggressive around age 45. Midlife crisis? Brain changes? Hormones? Empty nest syndrome? Seven year itch? When inventing explanations, one's powers of imagination are the only limit.

Hence the reason we don't take post-hoc explanations for apparent correlations very seriously. Such explanations are like a rustling in the leaves - might be the wind, might be an animal, might be a friend come to visit. We can't know without further investigation.

The Texas sharpshooter fires his rifle at the side of a barn repeatedly and randomly. He then searches for a cluster of shots close together and he draws a bullseye around them. We control for this kind of error by insisting that the researcher predict what he expects to find before seeing the data.

The alt med guys are Texas sharpshooters. They order hundreds of lab tests without first predicting what they expect to see or what those results might mean. Order enough tests and it's a statistical certainty that something will come back abnormal.

An honest researcher looking at the graph with the bump in aggressions around age 45 would say, "Could be this; could be that. Can't be sure without further study."

But here's the typical alt med doc:

Our group has found that toxin accumulation in the colon becomes critical by the age of 40. Take a look at this graph BigPharma doesn't want you to see...

Symptoms of CTS or Colonic Toxic Syndrome include:

- depression
- irritability
- low self-esteem
- bad breath
- stinky feet
- a tired feeling

If you haven't had regular colonic irrigations and think you might have CTS ...blah blah blah free consultation bogus testing and so on.

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