How to merge EARNWEEK variable from subsequent months to increase sample size in earlier non-March sample?

CPS
1

I am trying to generate a continuous income variable for respondents in non-March samples (specifically November). I cannot use the categorical version of the income variable available in this sample because I am using income to roughly calculate a person’s Federal Poverty Level (FPL) for that year. The best option that I could think of was to use the earnweek variable and combine it with any potential spouse’s earnkweek value (earnweek_sp). I understand that this is a flawed method for many reasons, but it is the best solution that I could devise. Before I continue with this question, is anyone aware of a better way to get a continuous income variable for the November supplement that would allow me to calculate FPL?

If not, as I proceed with using earnweek to calculate family income I have encountered a few problems. Given that earnweek is only asked in the outgoing rotation group, I wanted to attach the earnweek variable from the subsequent months that still had participants in the November sample (i.e. December, January, and February) to increase my sample size. I tried to link my IPUMS CPS sample from these months to the November sample using HRHHID, HRHHID2, and LINENO, but I return a number of false matches. (When I use race as the test variable, I get 8137 incorrect matches). If I include race and sex in the match, it doesn’t solve the problem. Do you know how I can merge this information without generating duplicates?

Once I solve this problem, I plan to append this generated “income” variable to every person in the same household. First, I plan to use the variable RELATE to delete anyone not part of the family by Federal Poverty Level-calculation standards. I can then extend the “income” variable to everyone remaining in the household by first creating a new variable called Fam_earnweek. I would then use YEAR, SERIAL, and PERNUM to uniquely identify households, and select the maximum value of Fam_earnweek within a given household to use for the household value. I would then drop all other records with the same serial number. I plan to then merge this household level information onto the original person-level data by using a many-to-one merge on YEAR, PERNUM, and SERIAL. Does this make sense?

My apologies for the length of these questions! I greatly appreciate your help.

2

As you have identified, EARNWEEK is the only continuous “income” variable in the November samples. Keep in mind that respondents not in the universe are given a value of 9999.99 for EARNWEEK. It also might be helpful if you read this User’s Note on calculating poverty rates, especially the discussion of what comprises a family unit. It may be worthwhile for your purposes to combine more than just spouse’s earnings.
Since the CPS interviews households, I suspect the discrepancies you are seeing in the race variable are due to a change in the residents of the interviewed household. To check on the accuracy of linking across months, I attempted to merge the December IPUMS CPS sample to the November IPUMS CPS sample (after sequentially merging both with the respective Basic CPS dataset). The unique identifiers I used were GESTCEN, HRHHID, HRHHID2, PRFAMNUM, and PULINENO (same as from this previous answer). Using age to check the merge, there were 7,982 differences (out of 95,264 households appearing in both months). However, all but 487 of these age differences were an increase of 1 year, which makes sense since a portion of the sample will have had a birthday in the time between the November and December surveys. Taking this into account, less than 100 of the persons that matched on age did not match on race or sex. In other words, less than 1% of the possible matches failed to match when judging by age, sex, and race.
The method you describe for creating a family income variable sounds reasonable.
Hope this helps.