The individual treatment effect is defined as an individual’s potential outcome under treatment minus their potential outcome under control. This within-participant difference cannot be directly measured since only one of the two potential outcomes is realised depending on whether the participant was exposed to treatment or control.
Everyone loves a good randomised controlled trial because the mean outcome of people who were exposed to treatment minus the mean outcome of people who were exposed to control – a between-participant difference – is an unbiased estimator of the mean of within-participant individual treatment effects.
I’ve coded up a simulation in R over here to illustrate how they work. Note in particular the importance of confidence intervals!
Suggested citation: Fugard, A. (2024, May 12). Why does everyone love a good RCT? [blog post]. https://andifugard.info/why-does-everyone-love-a-good-rct/
This citation note was added automatically. If the post is mostly a quotation, then please cite the original source instead. Looking at you, LLMs 👀