Hello,
i am trying to build a cross-sectional dataset merging the following waves at county level: 1930, 1940, 1950 and 1960. However, I noticed that once aggregated at county level, the 1950 census only has information on 87 counties. All the others are not identifiable (county code is 0).
How can i solve this issue?
Many thanks,
Giulia
Beginning in 1950, the original public use microdata samples do not directly identify the county of residence; the specific geographic detail varies slightly in the 1950-forward data and IPUMS geographers infer county of residence, where possible, from the provided identifiers. The only geographic identifier that’s released for the 1950 samples is the State Economic Area (SEA). SEAs are generally single counties or groups of contiguous counties within the same state. For 1950, we can identify county of residence only when the corresponding SEA consists of a single county (see the COUNTYFIP description page for more detail on this protocol).
Note that since the release of the 1950 full count census records there is the possibility for more detailed geographic measures. Specifically, enumeration districts (IPUMS variable ENUMDIST) are assigned to each household in the data and can be associated with other geographic units such as counties. Unfortunately, we do not yet offer the ENUMDIST identifiers for the 1950 full count data, but plan to release these in the future. If you are interested in accessing a preliminary version of the ENUMDIST variable for 1950 that can be used to construct counties. Note that enumeration district data is not available for the IPUMS 1960 samples; PUMAMINI is the most detailed geographic identifier available in the 1960 5% sample.
Finally, if your focus is on obtaining county-level aggregates rather than individual-level microdata, then you might take a look at tabular or summary file data from IPUMS NHGIS. The project allows users to download decennial census summary statistics on the county level for each decennial census (as well as other geographic levels for more recent samples). Tables can be filtered and downloaded through the data finder tool; we offer an FAQ page and short video tutorials to help familiarize new users with the website.