It is not clear to me whether randomc or keyfitz identify the PSUs. What is the difference between these two variables? I can’t locate the stratification variable. Are there any other ASEC data where income is collected as a continuous variable?
I am using the ASEC CPS March 1967 data. What variables identify the strata and primary sampling units?
RANDOMC and KEYFITZ are included in the original 1968 ASEC file, but the original 1967 ASEC file does not contain these variables. Rather, the 1967 file has a PSU number for each person and family: HPPSUNUM and HFPSUNUM, respectively. I recommend contacting the Census Bureau directly for further guidance on the difference between these variables found in the original CPS files.
Sorry that I could not be of more direct assistance.