Codes and Frequencies
Most IPUMS data transformations are performed using variable harmonization tables that specify how each value in the source data is recoded. Some variables also require programming logic in addition to the harmonization table. The harmonization documents for this variable are:
GEO1_ US1970 identifies the household's state within United States in 1970. States are the first level administrative units of the country. A GIS map (in shapefile format), corresponding to GEO1_ US1970 can be downloaded from the GIS Boundary files page in the IPUMS International web site.
The full set of geography variables for United States can be found in the IPUMS International Geography variables list. For cross-national geographic analysis on the first and second major administrative level of any country refer to GEOLEV1, and GEOLEV2. More information on IPUMS-International geography can be found here.
Comparability — General
The 1970 U.S. sample privileges the identification of metropolitan areas over states. If knowing both the state and metro area of residence would allow the identification of a subpopulation less than 250,000 persons, then state is coded to "State not identified"
The following states are coded to "State not identified":
- North Dakota
- South Dakota
- All households
- United States: 1970