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July 22, 1992

The Quality of Mercy Is Not Strained-Reply

JAMA. 1992;268(4):471-472. doi:10.1001/jama.1992.03490040047016

In Reply.  —Contrary to the comments of Dr Finder, our study1 satisfies all the criteria for a controlled trial.2 A controlled trial cannot begin, as Finder seems to suggest, by presuming a causal link between the intervention and the outcome. The purpose of a controlled trial is to test the hypothesis that the intervention is causally effective. This is accomplished by randomly selecting groups that are, to the best of the investigators' knowledge, the same in all respects except their exposure to the intervention. By observing differences in outcome for the experimental and the control groups, the causal hypothesis receives support. Our ethics education intervention was, to the best of our knowledge, the only systematic difference between the control and experimental groups of house officers. This supports the inference that our intervention caused the observed differences.Finder also questions which aspects of our intervention were effective. Education ought