Published 28 July 2009, doi:10.1136/bmj.b3035
Cite this as: BMJ 2009;339:b3035

Letters

Statistics for health

Let’s start with reporting

The first 150 words of the full text of this article appear below.

Clinical epidemiology is now well established. Therefore no article should be published without mentioning the number needed to treat. This is especially important when dealing with issues around medical prevention, such as statins.¹

Gigerenzer et al recommend using frequency statements instead of single event probabilities, absolute risks instead of relative risks, death rates instead of survival rates, and natural frequencies instead of conditional probabilities.²

They also say: "reporting relative risk reductions without clearly specifying the base rates is bad practice because it leads readers to overestimate the magnitude of the benefit. Consider one medication that lowers risk of disease from 20% to 10% and another that lowers it from 0.0002% to 0.0001%. Both yield a 50% relative risk reduction, yet they differ dramatically in clinical importance."

The communication of risks or therapeutic effects is a critical and responsible task. So why is a meta-analysis published without the number needed to . . . [Full text of this article]

¹ Medical University of Graz, 8010 Graz, Austria

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This doesn't make sense

Marko Tostad
bmj.com, 2 Aug 2009 [Full text]

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