The Empirical Evidence of Bias in Trials Measuring Treatment Differences

Steve Simon

2016-01-25

Figre 1. Exceprt from website

When I wrote a book about Evidence Based Medicine back in 2006, I talked about empirical evidence to support the use of certain research methodologies like blinding and allocation concealment. Since that time, many more studies have appeared, more than you or I could easily keep track of. Thankfully, the folks at the Agency for Healthcare Research and Quality commissioned a report to look at studies that empirically evaluate the bias reduction of several popular approaches used in randomized trials. These include

The general finding was that failure to use these bias reduction approaches tended to exaggerate treatment effects, but the magnitude and precision of these exaggerated effects was inconsistent.

Nancy D Berkman, P Lina Santaguida, Meera Viswanathan, and Sally C Morton. The Empirical Evidence of Bias in Trials Measuring Treatment Differences. Available in pdf format.

You can find an earlier version of this page on my blog.