| How can you distinguish between real placebo effects and get-better-anyway effect? The only way to measure the size of genuine placebo effects is to compare in an RCT the effect of a dummy treatment with the effect of no treatment at all.

I hear a lot about placebo effects, but I hadn't ever appreciated that regression to the mean might be a stronger factor.

ooli:

A classical example concern concerns the effectiveness of speed cameras. They tend to be installed after a spate of accidents, and if the accident rate is particularly high in one year it is likely to be lower the next year, regardless of whether a camera had been installed or not.

The Regression To the Mean effect seems to explain so many strange results! It's a powerfull tool for any skeptic around here.

posted 3053 days ago