Lauren Jones from U Toronto asks
I have a question about semantics. You use the word "random" to describe both the treatment assignment variables D in RCTs, and also to describe the outcome variables Y in regression analysis. "Random" means something different in the first application than in the second. Indeed, you explain that Y varies with "systematic randomness" (MHE p. 29), but I am still a little confused about how to square away the two uses of the word. Any help?
Good question, lauren. There are many sorts of randomness in the 'Metrics world: random variables, random samples, randomized trials. We try to make the distinction clear in our new book, Mastering 'Metrics