Also, in online analysis, if I am using the UNION variable does the sample automatically get reduced to the Outgoing Rotation Group?
For the union variable in the CPS, what is the difference between NIU (not in union) and "no union coverage"?
I’ll address each question one at a time.
First, the difference between NIU and UNION==1 “No union coverage” is the former identifies individuals who do not meet the universe definition for the UNION variable and the latter identifies individuals who do meet the universe definition, but do not have union coverage. For example, in the 2018 ASEC sample, the universe for UNION is defined as civilians 15+ years old who are currently employed as wage/salary workers and are asked “earner study” questions. So, individuals who do not fall inside this definition are UNION==0 “NIU” and those who do, but have no union coverage, are UNION==1 “No union coverage.”
Second, in the online analysis tool if you filter based on UNION > 0 then you will be filtering out anyone who is not eligible to answer the UNION question. Said differently, this effectively reduces the sample to those who meet the universe definition for UNION.