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ROBERT D. MAURO, MD
The Children's Hospital University of Colorado School of Medicine 1056 E 19th Ave Denver, CO 80218

Am J Dis Child. 1990;144(6):620-621.

	Since this article does not have an abstract, we have provided the first 150 words of the full text PDF and any section headings.

Sir.—I want to bring to your readers' attention the problem of type II errors in clinical research studies that reach conclusions of "no difference." Please forgive me as I cover some territory that is no doubt familiar, but I want to develop my argument fully.

An investigator typically analyzes data by subjecting them to a statistical test, to see whether the difference observed is likely to have resulted from chance alone. When P<.05, the investigator concludes that there is a less than 5% chance that a difference of this magnitude could have resulted from chance, and so he or she concludes that the difference is real. So far, so good. But what happens when P>.05? Many investigators unfortunately conclude, without further analysis, that the two outcomes studied are not different. What's worse, many medical journals let these investigators publish this erroneous conclusion. Merely knowing that P>.05 does not tell . . . [Full Text PDF of this Article]

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