2023 Migration Areas: Delineations and PUMA Correspondence

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Overview

The MIGMET23 variable identifies migration metropolitan areas using the 2023 delineations of metropolitan statistical areas (MSAs) from the U.S. Office of Management and Budget (OMB). This page provides information about these delineations and their correspondence to Migration Public Use Microdata Areas (MIGPUMA1).

Migration PUMAs are the only sub-state-level geographic area identified in public-use microdata samples from decennial censuses and the ACS/PRCS since 1990. Migration PUMAs occasionally straddle official metro area boundaries. To identify 2023 MSAs in microdata, IPUMS USA associates Migration PUMAs with MSAs by determining which (if any) MSA contains a majority of each Migration PUMA's population. See the MIGMET23 variable description for complete details on the identification approach.

MIGMET23's code assignment protocol yields errors of omission (residents of a MSA who are not identified as residents) and errors of commission (non-residents who are identified as residents). MIGMET23 reports no code for MSAs where the sum of match errors is 15% or more.

The crosswalks provided here describe all spatial associations between 2023 MSAs and PUMAs, including the population in each area of intersection. The match summaries identify the best-matching set of Migration PUMAs for each 2023 MSA (i.e., the Migration PUMAs where a majority of population resides in the MSA) along with omission and commission errors. Match summaries are provided for all 2023 MSAs, including those that exceed MIGMET23's 15% mismatch limit.

MIGMET23 is available only for 2012 and later samples. For information about other variables identifying migration metropolitan areas, see the geographic resources overview page: Geographic Tools and Resources.

Delineation File

The Census Bureau provides delineation files for every version of core-based statistical areas (CBSAs), which include both metropolitan and micropolitan statistical areas. (For definitions of these terms and related concepts, see the Census Bureau's Glossary for metropolitan and micropolitan areas.) Each CBSA corresponds to a set of counties. The delineation files identify which counties are in each CBSA along with other info: which areas are metropolitan or micropolitan, which counties are in a metropolitan division, which CBSAs are in a consolidated statistical area (CSA), and whether each county is classified as "central" or "outlying."

IPUMS USA provides a copy of the 2023 CBSA delineation file here:

MSA-MIGPUMA Crosswalks and Match Summaries

2022-2031 ACS and PRCS samples:

2012-2021 ACS and PRCS samples:

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