To the Editor.—
The long-awaited article on the National Institute of Mental Health (NIMH) research program comparing interpersonal psychotherapy (IPT), cognitive behavior (CBT), placebo case management (PLA-CM) and imipramine case management (imipramine-CM) has finally arrived!1 Outstanding is the lack of lucidity with regard to just what specific hypotheses are being tested. Since the meaningful pairwise contrasts are not stipulated, counterproductive and arbitrary significance level "adjustments" were inflicted on the data, thus obscuring the findings.It should be noted that all six contrasts between the four treatments are of clinical interest and public health importance. We want to know the relative merits of all the treatments. The logic of multigroup data analysis often proves difficult for the cally sophisticated reader, so I present a parable indicating why the Bonferroni correction, selected as the familywise type I error control strategy in this report, interferes with seeing real differences between the treatments.
Klein DF. NIMH Collaborative Research on Treatment of Depression. Arch Gen Psychiatry. 1990;47(7):682-684. doi:10.1001/archpsyc.1990.01810190082012