We would like to pool NHIS data for 2023 and 2024 to run analysis using geography breakdowns (urban vs rural). The comparability notes for URBRRL note two different NCHS classification schemes applied (Beginning with the 2024 sample, NCHS uses the 2023 NCHS Classification Scheme; for previous years they used the 2013 version.) The detailed documentation notes that these differences are small. Can this data be pooled, or is this considered a break in series for URBRRL? If we are unable to use URBRRL across 2023 and 2024, is there any other way to create an urban/rural variable outside of the RDC? Thank you!
The NCHS’s rules for assigning rural/urban status have not changed, but the delineations of metropolitan statistical areas and micropolitan statistical areas, as well as the population estimates, used to assign rural/urban status did change. Since the public data do not include any geographic identifiers that would allow you to make the urban/rural classification method more comparable between the samples, you have two options. First, you could use the data as they are, and make note of the change in any reports or publications. Alternatively, you could access more geographically detailed data in an RDC, which is a highly involved process. One indication of how much the change affected individuals’ urban/rural status classification is to look at how counties have been classified as urban versus rural under each classification scheme. The NCHS publishes this information. You may also find our documentation on and crosswalks for 2013 and 2023 MSAs from IPUMS USA helpful.