The explanation for sample design suggests that in 1970 dataset form 1 and form 2 contain a somewhat different set of variables. I didn’t find questionaire text. Could you tell me where I can find out what these different variables are? Thanks!
You can find the 1970 Census questionnaire here. Before each question, it indicates whether the question was included on Form 1 only, Form 2 only, or All Forms.
Hope this helps.