The death of SAS and SPSS in academia

Where is the growth? In R and Stata, of course: What’s interesting is the discrepancy between the death and growth rates. Mixed in here is a hidden trend, I believe, where scholars are much less likely in general to mention the statistical software they used in their research. http://r4stats.com/articles/popularity/

Understanding weight calculations in Stata’s psmatch2

If you’ve ever used psmatch2 in Stata, you know that it has one of the least useful help files ever created. I’ve always been frustrated with not understanding how the weights in psmatch2 are calculated, so I decided to sit down and figure it out. After running psmatch2 in Stata, the program creates a variable…

How to interpret interaction terms

I keep referring to this issue in manuscript reviews, so I thought it worth a post. If you include an interaction term in a model, the statistical significance of the main effects and the interaction term tells you nothing about the interactive effect. This seems contrary to your intuition. Turns out the interactive effect may…

Exporting Stata output

This is the most comprehensive list I have seen on all the different ways of exporting Stata output into Excel: http://www.cpc.unc.edu/research/tools/data_analysis/statatutorial/misc/exporting_results

Making my code public

My New Year’s resolution for 2014 is to publicly post all of my Stata code for my projects. Why? This will force me to be more careful with my code, even though I am already somewhat anal when it comes to my code.