Is it possible to map (U)OCC uniquely to OCC1950 in the 1940 100% data?

In the 1940 full count data, there appears to be no unique mapping between OCC1950 and OCC and UOCC variables. In particular, for some (U)OCC values there exists various values of OCC1950. So, based on the data, I don’t seem to be able to allocate individuals to OCC1950 categories.

How is the value for OCC1950 determined in these cases? After reading… I am not sure how to answer this question. Is there a key to uniquely map the two occupational variables?

Thank you!

In 1940, the Census Bureau made major changes in how it generated data on economic work. These changes lead to the identification of three distinct variables: industry (IND), occupation (OCC), and class of worker (CLASSWKR). In general, this information is used to classify individuals within the 1950 occupation classification scheme (OCC1950). So, it is very possible that there are a number of cases where OCC values exist for various values of OCC1950, because more information than just OCC was used to ‘re-classify’ occupation into the 1950 scheme. Typically, crosswalk tables are available to aid researchers in understanding the relationship between OCC and OCC1950 within a given sample. Unfortunately, no such crosswalk exists online for 1940 but, the IPUMS-USA Team has created one (see attached) and this will be available online soon.
1940_OCC_to_OCC1950.csv (16.5 KB)