This presentation updates Nichols and Schaffer's 2007 UKSUG talk on clustered standard errors. Although cluster-robust standard errors are now recognized as essential in a panel data context, official Stata only supports clusters that are nested within panels. This rules out the possibility of...

Several options for estimation and prediction in regressions using nonnegative skewed dependent variables are compared. Often, Poisson regression outperforms competitors, even when its assumptions are violated and the correct model is one that justifies a competitor.