Information Technology Reference
In-Depth Information
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Scientists eject us from their laboratories when we suggest that
only the animal caretakers be permitted to know which cage
houses the control animals.
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Engineers at a firm that specializes in refurbishing medical devices
objected when Dr. Good suggested that they purchase and test
some new equipment for use as controls. “But that would cost a
fortune.”
The statistician's lot is not a happy one. The opposite sex ignores us
because we are boring,
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and managers hate us because all our suggestions
seem to require an increase in the budget. But controls will save money in
the end. Blinding is essential if our results are to have credence, and care
in treatment allocation is mandatory if we are to avoid bias.
Randomize
Permitting treatment allocation by either experimenter or subject will
introduce bias.
Controls
To guard against the unexpected, as many or more patients should be
assigned to the control regimen as are assigned to the experimental one.
This sounds expensive and is. But shit happens. You get the flu. You get a
headache or the runs. You have a series of colds that blend one into the
other until you can't remember the last time you were well. So you blame
your silicone implants. Or, if you are part of a clinical trial, you stop
taking the drug. It's in these and similar instances that experimenters are
grateful they've included controls. This is because when the data are
examined, experimenters learn that as many of the control patients came
down with the flu as those who were on the active drug, and they also
learn that those women without implants had exactly the same incidence
of colds and headaches as those who had implants.
Reflect on the consequences of not using controls. The first modern sili-
cone implants (Dow Corning's Silastic mammary prosthesis) were placed
in 1962. In 1984, a jury awarded $2 million to a recipient who com-
plained of problems resulting from the implants. Award after award fol-
lowed, the largest being more than $7 million. A set of controlled
randomized trials was finally begun in 1994. The verdict: Silicon implants
have no adverse effects on recipients. Tell this to the stockholders of bank-
rupt Dow Corning.
Use positive controls.
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Dr. Good told his wife he was an author—it was the only way he could lure someone that
attractive to his side. Dr. Hardin is still searching for an explanation for his own good
fortune.
