Recently I demonstrated a common incorrect technique for comparing percentage rate performances—based of course in the usual normal distribution nonsense. Let’s revisit those data with a superior alternative.

To quickly review the scenario: In an effort to reduce unnecessary expensive prescriptions, a pharmacy administrator developed a protocol to monitor and compare individual physicians’ tendencies to prescribe the most expensive drug within a class.

Data were obtained for each of a peer group of 51 physicians—the total number of prescriptions written and how many of them were for the target drug. During this time period, these 51 physicians had written 4,032 prescriptions, of which 596 were for the target drug—an overall rate of 14.8 percent.

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