Stata 11 Factor Variable / Margins Links
| Gabriel |
Michael Mitchell posted a brief tutorial on factor variables. (This has nothing to do with the “factor” command — think interaction terms and “xi,” not eigenvectors and structural equations). People who are already familiar with FV won’t really get anything out of the tutorial, but should serve as a very good introduction for people who are new to this syntax. Like all of Mitchell’s writing (e.g., the graphics book) it is very clearly written and generally well-suited to the user who is transitioning from novice to advanced usage.
The new Stata newsletter has a good write-up of “margins” syntax, which is useful in conjunction with factor variables for purposes of interpreting the betas (especially when there’s some nonlinearity involved). In a recent post explaining a comparable approach, I said that my impression was that margins only really works with categorical independent variables, but I’m please to see that I was mistaken and it in fact works with continuous variables as well.