It’s always a pleasure to meet an introduction that combines elegance with a powerful punch.
In this case, it comes from an article published in the CMAJ, the Canadian Medical Association’s journal, explaining the difference between absolute risk reduction, relative risk reduction, and number needed to treat.
The article aims to help clinicians in their decision making, but these are also useful concepts for patients – or anyone involved in making treatment decisions – to understand.
Here is the introduction:
“Physicians, patients and policy-makers are influenced not only by the results of studies but also by how authors present the results.
Depending on which measures of effect authors choose, the impact of an intervention may appear very large or quite small, even though the underlying data are the same.”
An international group of authors – the “evidence-based medicine teaching tips working group” – is responsible for the article, including Associate Professor Alexandra Barratt from the Sydney School of Public Health, University of Sydney.
The article was published in 2004, but as it is now being circulated via Twitter, I thought I’d pass it on. It doesn’t hurt to be reminded of the merits of interrogating the presentation of data.