Two-Stage Regression and Multilevel Modeling: A Commentary
These articles demonstrate, in several different examples, the effectiveness of two-level regression: the procedure of fitting several separate regression models, and then fitting a second, higher-level, regression to the estimated coefficients (for example, fitting a separate regression model to survey data from each of several countries, then regressing the coefficient estimates on country-level predictors). For simplicity, we will refer to the first- and second-level units as “persons” and “countries,” respectively, but our points apply more generally.