From the first sight, it seemed clear how to analyze data using DRM in R. However, when I started to build my models I found that have problems to get estimates for all variables in a model. I got NA each time when I add control characteristics.
My dependent variable is numeric. I have social origin and destination of people. I create social mobility patterns and I have several control characteristics.
In common way the simple script looks like:
MODEL00 <- gnm (LN ~ -1 + Dref (EDUC_PAR, EDUC_MY, delta = ~ 1 + downward + upward),
constrain = "delta1",
family = gaussian,
data = data1,
verbose = F)
When I added smth else (sex or age) I got NA instead estimations. What am I missing?