Description

CITY identifies the city of residence for households located in identifiable cities. The Comparability section provides a discussion of factors affecting which cities are identified and how well they are represented in each sample.

The identified cities are generally consistent with U.S. Census "place" definitions. For an explanation and history of the concept, see Chapter 9 in the Census Bureau's Geographic Areas Reference Manual.

Comparability

This variable is essentially comparable across years, but not all cities are identified in all years, and there are some variations in the exact correspondence between CITY codes and city residents. A year-by-year discussion follows. All rank and size measurements refer to contemporary (not current) population figures, unless otherwise noted:

• 1990, 2000, 2010, ACS and PRCS: In source PUMS files since 1990, the most detailed geographic information available is for Public Use Microdata Areas (PUMAs), which are designed to contain at least 100,000 residents each. (See Geographic Tools for detailed PUMA maps and composition lists.) PUMAs are sometimes coterminous with city boundaries, but they also frequently encompass multiple cities and occasionally straddle city boundaries. Therefore, for most cities, and even for some very large cities, it is impossible to identify the exact set of corresponding PUMS records.

The protocol used for the CITY variable in 1990 and later samples is to identify the city in which the majority of each PUMA's population resided. Where a city is identified, it indicates that, for the PUMA in which the household resided, a majority of the PUMA's population resided in the identified city, according to population counts from the reference census for the PUMA definitions (e.g., 2000 populations for 2000 PUMAs). A household might not in fact have resided in its identified city, but given its PUMA's population distribution, it is likely that the household resided in the city.

This protocol yields errors of omission (where a CITY code is not assigned to some residents of the corresponding city) and errors of commission (where a CITY code is assigned to some non-residents). As an index of mismatch for each CITY code, IPUMS uses the sum of percent omission error (the portion of a city's population residing in excluded PUMAs) and percent commission error (the portion of the population in associated PUMAs that did not reside in the city).

To ensure that CITY codes are generally representative of city populations, cities are identified only where the sum of match errors is less than 10%.

For each CITY code in 1990 and later samples, the CITYERR variable identifies the level of the sum of errors. Researchers may use CITYERR to impose a more restrictive error limit if desired.

For census samples, CITY identification is based on the PUMAs, place definitions, and population counts associated with the corresponding census. For ACS and PRCS samples, CITY identification is based on census information corresponding to the PUMA definitions used in the source samples, as follows:

• 2022-forward ACS/PRCS: 2020 PUMAs, places, and population

• 2012-2021 ACS/PRCS: 2010 PUMAs, places, and population

• 2005-2011 ACS/PRCS: 2000 PUMAs, places, and population

In multi-year ACS/PRCS samples that span different PUMA definitions, this variable is based on whichever PUMA definition is associated with the respondent's survey year (as given by MULTYEAR). This occurs only in the 2022 5-year samples and in multi-year samples that include both 2011 and 2012 survey years. For more information about how PUMA definitions vary within multi-year samples, see the PUMA variable description.

For more detailed information about PUMA-city relationships and CITY match errors, IPUMS provides these tables (in Excel spreadsheets) summarizing relationships between PUMAs and "large" places, defined here as places with populations exceeding 75,000:

• Crosswalk Between Large Places and 2020 PUMAs

• PUMA Match Summary by Large Place

• Crosswalk Between Large Places and 2010 PUMAs

• PUMA Match Summary by Large Place

• Crosswalk Between Large Places and 2000 PUMAs

• PUMA Match Summary by Large Place

• Crosswalk Between Very Large Places (>300,000 Population) and 2000 Super-PUMAs

• Super-PUMA Match Summary by Very Large Place (>300,000 Population)

• Crosswalk Between Large Places and 1990 5% PUMAs

• PUMA Match Summary by Large Place

• Crosswalk Between Large Places and 1990 1% PUMAs

• PUMA Match Summary by Large Place

• 1980: The State, Metro, and Urban/Rural samples cover geography differently (see Sample Designs). The State and Metro samples identify the city of residence for households in many, but not all, cities with populations of 100,000+, but the State and Metro lists of identifiable cities are not the same. In the Urban/Rural sample, only the central cities of urbanized areas are identified; see URBAREA for a definition of urbanized areas. In some instances in the Urban/Rural sample, urbanized areas have multiple central cities; these central cities cannot be identified separately. The following cities are combined for purposes of CITY in the 1980 Urban/Rural sample, and receive the code of the first city listed below (the largest):

• 1950 100%: The city of residence is given for households in any city with 10,000+ inhabitants.

• 1940 1% and 1950 1%: The city of residence is given for households located in central cities of metropolitan areas only if the metropolitan central city and the remainder of the metropolitan area each had a population of 100,000+ (a total minimum of 200,000+) in 1980. In the 1940 and 1950 samples, a city can only be identified if it was the central city of a metropolitan area. Some metropolitan areas had more than one central city. In 1940 and 1950, the following cities share the same city code (i.e., they cannot be separately distinguished in the samples). Each city combination receives the code of the first city (the largest):

• 1920 and 1930: The city of residence is given for households in any city with 25,000+ inhabitants. For corresponding variables on the Puerto Rican barrios (township) and pueblos (city) codes in 1910 and 1920, see PRTWNSHP and PRCITYCO, respectively.

• 1900 and 1910: The city of residence is given for households in any city with 25,000+ inhabitants. For corresponding variables on the Puerto Rican barrios (township) and pueblos (city) codes in 1910 and 1920, see PRTWNSHP and PRCITYCO, respectively.

• 1860 and 1870: The city of residence is given for households in any city with 10,000+ inhabitants.

• 1850 and 1880: The city of residence is given if the household was in one of the nation's 98 largest cities.

Universe

Availability

• 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: All samples
• 2014: All samples
• 2013: All samples
• 2012: All samples
• 2011: All samples
• 2010: All samples
• 2009: All samples
• 2008: All samples
• 2007: All samples
• 2006: All samples
• 2005: All samples
• 2004: --
• 2003: --
• 2002: --
• 2001: --
• 2000: 5%; 1% old; 1% unwt; 1%
• 1990: 5% state; 1% metro; 1% unwt; 3% elderly
• 1980: 5% state; 1% metro; 1% urban
• 1970: --
• 1960: 5%
• 1950: All samples
• 1940: All samples
• 1930: All samples
• 1920: All samples
• 1910: All samples
• 1900: All samples
• 1880: All samples
• 1870: All samples
• 1860: All samples
• 1850: 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: All samples
• 2014: All samples
• 2013: All samples
• 2012: All samples
• 2011: All samples
• 2010: All samples
• 2009: All samples
• 2008: All samples
• 2007: All samples
• 2006: All samples
• 2005: All samples
• 2000: All samples
• 1990: --
• 1980: --
• 1970: --
• 1930: All samples
• 1920: --
• 1910: --

Flags

Editing Procedure

There is no editing procedure available for this variable.