Why is this the case? Are these variables created variables? Thank you.
INCLONGJ corresponds to the variable ERN_VAL (Question 48aa) in the original March ASEC data. This question asks for the income earned from the employer for whom the respondent worked for longest during the previous year.
I hope this helps. Please let us know if there are any other IPUMS-CPS variables you are having difficulty matching to the original CPS questionnaire.