Why is the URBAN variable in IPUMS-USA unavailable in 1950? Can URBAN be constructed from the available data?

Why is the URBAN variable in IPUMS-USA unavailable in 1950? Can URBAN be constructed from the available data?

An urban status variable was not included in the release of the public use sample for 1950. Thus, we do not have information on urban status and as a result cannot create such a variable. I don’t think any of the other geographic variables would allow one to create this variable in 1950, either.