Description

For respondents who lived in a different residence 1 year before the survey date, MIGMET23 identifies the metropolitan area where the respondent lived at that time if the prior residence was in an identifiable metropolitan area.

A metropolitan area, or metro area, is a region consisting of a large urban core together with surrounding communities that have a high degree of economic and social integration with the urban core.

MIGMET23 identifies metro areas using the 2023 definitions for metropolitan statistical areas (MSAs) from the U.S. Office of Management and Budget (OMB). The 2023 MSAs are the first to be based on 2020 standards and 2020 census data.

Note that the 00000 code applies to individuals who lived in the same residence 1 year ago as well as those whose previous residence was not in an identifiable metro area. Users who wish to distinguish these two conditions should use MIGRATE1 in conjunction with MIGMET23.

Inexact Correspondence with Official Delineations
IPUMS determines MIGMET23 codes based on Migration PUMAs (MIGPUMA1).

Because Migration PUMAs occasionally straddle official 2023 MSA boundaries,
MIGMET23 cannot identify the exact set of households residing in each metro area
.

The protocol IPUMS uses for MIGMET23 is to identify the MSA in which the majority of each Migration PUMA's population resided. If MIGMET23 identifies a metro area for a given respondent, it indicates that, for the Migration PUMA in which the respondent previously resided, a majority of the population resided in the identified metro area.

Match Errors and Code Suppression
MIGMET23's code assignment protocol yields errors of omission (residents of a metro area who are not identified as residents) and errors of commission (non-residents who are identified as residents). Migration PUMAs often nest within MSA boundaries, resulting in small match errors. For many metro areas, however, especially smaller metro areas, the Migration PUMAs are a poor match.

As an index of mismatch, IPUMS uses the sum of percent omission error (the portion of an MSA's population residing in excluded PUMAs) and percent commission error (the portion of the population in associated PUMAs that did not reside in the MSA).

MIGMET23 reports no code for MSAs where the sum of match errors is 15% or more.

For each reported MIGMET23 code, the MIGMET23ERR variable identifies the level of the sum of errors. Researchers may use MIGMET23ERR to impose a more restrictive error limit if desired.

To compute match errors, IPUMS uses 2020 populations for 2022-2031 ACS and PRCS samples and 2010 populations are used for 2012-2021 ACS and PRCS samples.

For detailed information about 2023 MSA delineations and their correspondence with Migration PUMAs, see the 2023 Migration Areas geographic resource page.

Comparability

MIGMET23, based on 2023 MSA delineations, is available only for ACS and PRCS samples. MIGMET131, based on 2013 MSA delineations, is also available only for ACS and PRCS samples. For the 2005-2011 samples, another variable, MIGMETAREA1, identifies previous metro area of residence using older metro area delineations and a different coding scheme. For earlier decennial census samples, the metro area of previous residence is identified by the MIGMETAREA5 and MIGMET135 variables.

MIGMET23 and MIGMET135 differ from MIGMET1 and MIGMETAREA5 in several ways:

• Delineation base year: MIGMETAREA1 and MIGMETAREA5 use different metro area delineations for different samples, generally following the delineations in use at the time of each decennial census and following the 1999 OMB delineations for all ACS and PRCS samples through 2011. The MIGMET13 variables use only the 2013 OMB delineations and the MIGMET23 variables use only the 2023 OMB delineations.
• County basis: For samples from 1950 through 2011, MIGMETAREA1 and MIGMETAREA5use OMB delineations that are county-based, defining each metro area as a set of one or more contiguous counties, except in New England, where each metro area is defined as a set of cities or towns. The 2013 delineations used by MIGMET13 and 2023 delineations used by MIGMET23 variables are instead entirely county-based, even in New England.
• Code scheme: MIGMETAREA1 and MIGMETAREA5 use 4-digit codes based on 1990 and 1999 OMB codes, but with several adjustments to reflect historical hierarchical relationships among metro areas. The MIGMET13 and MIGMET23 variables instead use the 5-digit 2013 and 2023 OMB codes, respectively, with no adjustments, making it easier to associate MIGMET13/MIGMET23 codes with data from other sources where the OMB codes are used.
• Representativeness: MIGMETAREA1 and MIGMETAREA5 identify metro areas only for previous residents of areas that lie entirely within a single metro area, which prevents errors of commission (no non-residents of a metro area are identified as residents), but it puts no limit on errors of omission (sizable portions of many metro areas' populations are not identified by MIGMETAREA1 and MIGMETAREA5). The MIGMET13 and MIGMET23 variables instead use a majority-assignment protocol that aims to maximize representativeness and they suppress codes for areas where the sum of omission and commission errors is 15% or more.
• Error reporting: IPUMS does not currently supply a summary of the omission errors in MIGMETAREA1 and MIGMETAREA5 identifications. For the MIGMET13 and MIGMET23 variables, IPUMS supplies separate variables, MIGMET13ERR and MIGMET23ERR, that indicate the combined omission and commission error by metro area.

Universe

Availability

• 2024: All samples
• 2023: All samples
• 2022: All samples
• 2021: All samples
• 2020: All samples
• 2019: All samples
• 2018: All samples
• 2017: All samples
• 2016: All samples
• 2015: ACS
• 2014: ACS
• 2013: ACS
• 2012: ACS
• 2011: --
• 2010: --
• 2009: --
• 2008: --
• 2007: --
• 2006: --
• 2005: --
• 2004: --
• 2003: --
• 2002: --
• 2001: --
• 2000: --
• 1990: --
• 1980: --
• 1970: --
• 1960: --
• 1950: --
• 1940: --
• 1930: --
• 1920: --
• 1910: --
• 1900: --
• 1880: --
• 1870: --
• 1860: --
• 1850: --

• 2024: All samples
• 2023: All samples
• 2022: All samples
• 2021: All samples
• 2020: All samples
• 2019: All samples
• 2018: All samples
• 2017: All samples
• 2016: All samples
• 2015: PRCS
• 2014: PRCS
• 2013: PRCS
• 2012: PRCS
• 2011: --
• 2010: --
• 2009: --
• 2008: --
• 2007: --
• 2006: --
• 2005: --
• 2000: --
• 1990: --
• 1980: --
• 1970: --
• 1930: --
• 1920: --
• 1910: --

Flags

Editing Procedure

There is no editing procedure available for this variable.