Clustered standard errors in Stata

Abstract

A brief survey of clustered errors, focusing on estimating cluster–robust standard errors: when and why to use the cluster option (nearly always in panel regressions), and implications. Additional topics may include using svyset to specify clustering, multidimensional clustering, clustering in meta-analysis, how many clusters are required for asymptotic approximations, testing coefficients when the Var–Cov matrix has less than full rank, and testing for clustering of errors.