Description

For respondents who lived in a different residence 5 years before the census, MIGMET135 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.

MIGMET135 identifies metro areas using the 2013 definitions for metropolitan statistical areas (MSAs) from the U.S. Office of Management and Budget (OMB). The 2013 MSAs are the first to be based on 2010 standards and 2010 census data.

The metro area delineations and codes used by MIGMET135 are consistent with those used by MIGMET131, which identifies the metro area of residence one year ago for ACS and PRCS samples.

Note that the 00000 code applies to individuals who lived in the same residence 5 years 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 MIGRATE5 in conjunction with MIGMET135.

Inexact Correspondence with Official Delineations
IPUMS determines MIGMET135 codes based on Migration PUMAs (MIGPUMA5), which are the only sub-state geographic units identified in the source PUMS data for previous residence.

Because Migration PUMAs occasionally straddle official MSA boundaries, MIGMET135 cannot identify the exact set of households residing in each metro area.

The protocol IPUMS uses for MIGMET135 is to identify the MSA in which the majority of each Migration PUMA's population resided. If MIGMET135 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 2000 population resided in the identified metro area.

Match Errors and Code Suppression
MIGMET135'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).

MIGMET135 reports no code for MSAs where the sum of match errors is 15% or more.

For each reported MIGMET135 code, the MIGMET13ERR variable identifies the level of the sum of errors. Researchers may use MIGMET13ERR to impose a more restrictive error limit if desired.

To compute match errors, IPUMS estimates the populations of the areas of intersection between 2000 Migration PUMAs and 2013 MSAs by summing the populations of 2000 census blocks that had their geographic center in each area.

For more detailed information about relationships between Migration PUMAs and MSAs and about MIGMET135 match errors, IPUMS provides these tables (in Excel spreadsheets):

• Crosswalk Between 2013 MSAs and 2000 Migration PUMAs

• MIGMET135 Omission and Commission Errors by MSA

Codes

This variable is not available for any of the currently selected samples.

Comparability

MIGMET135 is available only for 2000 census samples. Another variable, MIGMET5, also identifies the metro area of previous residence for 2000 samples as well as for earlier decennial censuses.

MIGMET135 differs from MIGMET5 in several ways:

• Delineation base year: MIGMET5 uses different metro area delineations for different samples, generally following the delineations in use at the time of each decennial census. MIGMET135 uses only the 2013 OMB delineations.
• County basis: The metro area delineations used by MIGMET5 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 variables are instead entirely county-based, even in New England.
• Code scheme: MIGMET5 uses 4-digit codes based on 1990 and 1999 OMB codes, but with several adjustments to reflect historical hierarchical relationships among metro areas. MIGMET135 instead uses the 5-digit 2013 OMB codes with no adjustments.
• Representativeness: MIGMET5 identifies 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 MIGMET5). MIGMET135 instead uses a majority-assignment protocol that aims to maximize representativeness. MIGMET135 also suppresses codes for areas where the sum of omission and commission errors is 15% or more.
• Error reporting: IPUMS does not at this time supply a summary of the omission errors in MIGMET5 identifications. For MIGMET135, IPUMS supplies a separate variable, MIGMET13ERR, that indicates the combined omission and commission error by metro area.

Universe

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• 2000: PR 5%
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Flags

Editing Procedure

There is no editing procedure available for this variable.