Beginning with the release of the 2018 CPS-ASEC migration tables, in the metropolitan migration tables the descriptions of one of the geography categories, in a metropolitan area but not in the principal city, were updated to read “balances of metropolitan areas” instead of “suburbs.” This is consistent with the CPS-ASEC technical documentation, which includes more details about migration-related variables. See also information about metropolitan and micropolitan status.
In Historical Table A-3, previous entries reading suburbs (2017 and earlier) and entries reading central cities (2003 and earlier) are kept in place. While balances of metropolitan areas and suburbs have been defined in the same way, the definition of central cities differs somewhat from that of principal cities. In the corresponding Historical Figure A-3, the labels balances of metropolitan areas, nonmetropolitan areas, and principal cities (of metropolitan areas) are used for simplicity. However, migration data users should note these changes in definitions and labels over time, especially when comparing with data from 2003 and earlier.