I am participating in a Project with data from a complex survey. We are going to analyze data from a national fertility survey. Some of the questions in the questionnaire were only asked by a subsample. For example, a question about the job was only asked to employed people. This variable and others like that are important in our study and we would like to include it in our logistic model. What approach do you recommend? I have seen in some papers of this area to set up another category “else”, that is, they combine other people (to which the question was not raised) creating an additional category. If this approach is acceptable, should i attributed random values to the income variable in order to reduce bias?
I will be very grateful if you could help me.