Selecting variables for Food Security Supplement

Analyzing the FSS, my results do not match published figures unless I filter for the RELATE variable

where RELATE eq 101

That matches USDA documentation and IPUMS codebook and works well.

To get RELATE and any other demographic variables, the IPUMS extract pulls the full December sample rather than just the FSS.

Extracting the FSS itself for the 2000s gets over 4 million records. Adding the necessary RELATE and any other demographic variables makes the extract over 8 million records. But for the analysis, I am using only households that completed the survey


That yields the 2.4 million records I am actually using.

Unless I’m mistaken, I cannot use the FSSUPINT variable in SELECT CASES to filter the extract. I don’t mind pulling millions of extra records and filtering them out on my end. I just feel like it’s a very inefficient use of the IPUMS resource to pull many times more records than I’m using.

Is there a better way to be doing the extract?

Thank you.

Dan Keating

Filtering to include only one observation per household is the correct way to conduct household-level analyses of the food security supplement variables; using RELATE = 101 is one way to do so, though we typically recommend filtering to observations with PERNUM = 1 instead. This will allow you to use FSHWTSCALE and FSSUPPWTH to produce estimates regarding households that are representative of the U.S. population (e.g., the percent of households that are food insecure). Researchers may also want to conduct individual-level analyses to estimate, for example, the percent of children under 18 who live in food insecure households. In this case, users should retain all cases of RELATE/PERNUM and use the FSS person weight FSSUPPWT.

You are correct that FSSUPINT can’t be used with the select cases tool. As a result, you will need to filter these observations using a stats package once you’ve downloaded the entire extract. Because of occasional cases that don’t adhere to expected universes in the CPS data (in particular for supplement eligibility or completion flags), we have not historically offered variables like FSSUPINT for case selection. I have, however, shared this idea with the IPUMS CPS team to consider.