Hi Mark! On Sun, Jan 3, 2010 at 9:08 PM, Mark Bulling <mark.bull...@googlemail.com> wrote: > Hi there > > Within sampleSelection, I'm trying to calculate the marginal effects for > variables that are present in both the selection and outcome models. > > For example, age might have a positive effect on probability of selection, > but then a negative effect on the outcome variable. i.e. > Model<-selection(participation~age, frequency~age, ...) > > Documentation elsewhere describes one method for doing this in Stata based > on Sigelman and Zeng: http://polisci.osu.edu/prl/Selection%20Models.pdf - > see page 16. > > I'd like to replicate this in r, but wanted to check I'm not reinventing the > wheel, before doing so.
I don't know a function/method that does this in R. So if you want to implement this in R, I suggest that you add a "marginalEffects" (or similar) method for objects of class "selection" to the "sampleSelection" package. You can get (write) access to the source code of this package on R-Forge [1]. Please let me (and Ott) know if you need any assistance. [1] http://r-forge.r-project.org/projects/sampleselection/ /Arne -- Arne Henningsen http://www.arne-henningsen.name ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
