Description

MIGCOGRP identifies the county group where the respondent lived 5 years ago. 1980 county groups are (usually) contiguous areas of 100,000+ residents, consisting of single counties, groups of counties, or other census-designated "places," defined by the Census Bureau to meet confidentiality requirements.

For the most part, the same state-dependent codes were used for county group of current residence (in CNTYGP98) and county group of residence 5 years ago (in MIGCOGRP). In six counties in Michigan (Genesee, Kalamazoo, Kent, Macomb, Oakland, and Wayne), there are discrepancies between the two. The differences arise because "county groups" are defined in terms of townships in CNTYGP98, but migration data were not coded to the township level in Michigan. For MIGCOGRP, the original county groups are approximated in terms of designated places and the remainders of the affected counties outside of places. In some cases, the approximation is very close; at worst, county groups can be combined to achieve coincidence between areas for current and past residence (see Codes, below).

Responses to questions about migration in the 1980 census were coded for only half the persons included in the IPUMS. These cases provide accurate proportional distributions but not correct absolute numbers for the general population. For correct absolute numbers, users should select cases coded as 2 in MIGSAMP and multiply by 2 as well as by PERWT.

MIGCOGRP is a 3-digit numeric code identifying the county group where the respondent lived 5 years ago. MIGCOGRP specific variable codes for missing, edited, or unidentified observations, observations not applicable (N/A), observations not in universe (NIU), top and bottom value coding, etc. are provided below by Census year (and data sample if specified).

MIGCOGRP Specific Variable Codes
000 = N/A
999 = Same house

See the 1980 County Groups: Detailed Composition and Boundary files for detailed composition of County Groups.

User Note [1]: 1980 County Group and Composition Map for Puerto Rico are currently unavailable.

User Note [2]: For people who lived in a US state outside of PR in 1975, values higher than "25" point to the county groups in that particular state.

Comparability

This variable is only available for 1980. In other years, the Census Bureau designated other areas of 100,000+ residents for analyzing place residence of five years ago. For 1940, the geographic unit is State Economic Area, and the analogous migration variable is MIGSEA5. For 1990 and the 5-percent sample of census 2000, the geographic unit is the Public Use Microdata Area (see PUMA), and the analogous migration variable is MIGPUMA. For the 1-percent sample of census 2000, the geographic unit is the Super-PUMA of 400,000+ residents (see PUMASUPR), and the analogous migration variable is MIGPUMAS. See MIGRATE5 for discussion of general issues relating to the measurement of migration using census data.

Universe

Availability

• 2023: --
• 2022: --
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• 2000: --
• 1990: --
• 1980: 5% state; 1% metro
• 1970: --
• 1960: --
• 1950: --
• 1940: --
• 1930: --
• 1920: --
• 1910: --
• 1900: --
• 1880: --
• 1870: --
• 1860: --
• 1850: --

• 2023: --
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• 1990: --
• 1980: All samples
• 1970: --
• 1930: --
• 1920: --
• 1910: --

Flags

Editing Procedure

There is no editing procedure available for this variable.