Forum: open-discussion

Issues with Weight and base category of Dummies in mvProbit [ Reply ]
By: Arnob Hoque on 2013-02-27 06:13

Hi Arne
I am a new user in R.
I am using multivariate probit to model farmers' simultaneous crop adoption decision. Most of my independent variables are category variables. For estimation, I am considering mvProbit in R. Is there any difference between Stata's "mvprobit" package and R's "mvProbit" package? The results I am getting using Stata and R does not match. One impression I have is that maybe the two packages are not using same categories of the "category variables" as base category. Is there any other reason for the results to be different?

I wonder what mvProbit in R is treating as base category for the category variables. For example if "age is a category variable in my model with 3 categories "less than 50" , "50-65" and "above 65", which one would the package consider as base category? My understanding is that it is not considering the lowest category as base category. How can I check in "R" which category of each variable has been considered as base category?

Since the estimation results in R with mvProbit are given without label( gives as as b_2_0, b_2_1, b_2_2....b_3_0, b_3_1...), I cannot identify which categories are omitted as base category. Is there any way I can set the option to see the label of variables in the result instead?

In addition, would you please tell how to use weights in mvProbit directly?

Asking too many questions in one thread. Thanks and appreciation in advance.