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Census tract

From Wikipedia, the free encyclopedia

Acensus tract,census area,census districtormeshblock[1]is a geographic region defined for the purpose of taking acensus.[2]Sometimes these coincide with thelimitsofcities,townsor other administrative areas[2]and several tracts commonly exist within a county. Inunincorporated areasof the United States these are often arbitrary, except for coinciding withpolitical lines.

Census tracts represent the smallest territorial entity for which population data are available in many countries.[3]In the United States, census tracts are subdivided intoblock groupsandcensus blocks.In Canada they are divided into dissemination areas. In the U.S., census tracts are "designed to be relatively homogeneous units with respect to population characteristics, economic status, and living conditions" and "average about 4,000 inhabitants".[4]

By country

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Brazil

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TheBrazilian Institute of Geography and Statisticsuses the termcensus sector(setor censitário).[5]As of the 2010 Census, there were approximately 314,000 sectors in Brazil.

France

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In 1999 in France, in order to prepare for the dissemination of the 1999 French population census, INSEE (Institut national de la statistique et des études économiques) developed a system for dividing the country into units of equal size, known as IRIS2000, but now known simply as 'IRIS'.[6]The acronym stands for 'Ilots Regroupés pour l'Information Statistique' (‘aggregated units for statistical information')[7]and the 2000 in the name referred not only to the upcomingmillenniumyear but to the target size of 2,000 residents per basic unit. Since 1999, IRIS has represented the fundamental unit for dissemination of infra-municipal data in France and itsoverseas departments and regions.Towns with more than 10,000 inhabitants, and a large proportion of towns with between 5,000 and 10,000 inhabitants, are divided into several IRIS units. France is composed of around 16,100 IRIS in total, of which 650 are in the overseas departments.[6]There are 3 types of IRIS unit in use: residential IRIS (pop. between 1,800 and 5,000), business IRIS (containing more than 1,000 employees) and miscellaneous IRIS (specific large zones which are sparsely inhabited and have large surface areas (leisure parks, ports, forests etc.).[6]

Ireland

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In theRepublic of Ireland,theCentral Statistics Office(CSO), established in 1949, organises the census.[8]Beginning from the 2011 census, the CSO website has made available "Small Area Population Statistics" (SAPS) for each "small area",a subdivision of anelectoral division(ED) defined byOrdnance Survey Irelandconstrained by natural landscape features.[9]Formerlymain roadsalso constrained the borders but this was changed to increasedata privacy.[9]A small area has a minimum of 65 and average of 90households.[9]For the 2016 census there were 18,641 small areas.[10]The 2016 census also provides the population of each of 50,117townlands,except those with a population of one sex or two people.[10]

From 1926 to 2006, the smallest unit of public reporting was the electoral division (till 1996 called "district electoral divisions" in counties or "wards"in the cities). There were 3,409 EDs in 2016.[10]Until 1911, the smallest reported unit was the townland in rural areas and the ward in urban areas. Subsequently, townland data was available on application to the CSO. All of the aforementioned are legally defined administrative units, although with no local government functions. From 1996 to 2006, "census enumeration areas" were included in data made available on request for areas within the fivecounty boroughsbut not the 29administrative counties.A census enumeration area was the area covered by a single enumerator, and had an average of 330 households.[11]This data has since been published online.[12]

New Zealand

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Main article:Mesh blocks

In New Zealand census tracts are known asmeshblocks,ormesh blocks,and are defined byStatistics New Zealandas being "the smallest geographic unit for which statistical data is collected and processed by Statistics New Zealand". It is a defined area, varying in size from part of a city block to large areas of rural land. Each of these borders another to form a network covering the whole country including inlets and coasts, and extending out to the 200 mileeconomic zone.Meshblocks are added together to "build up" larger geographic areas such as area units and urban areas. They are also used to draw up and defineNew Zealand electoratesandlocal authority boundaries.[1]

United Kingdom

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See also:ONS coding system

British census tracts were first developed in the city ofOxford.The Inter-University Census Tract Committee was formed in 1955[13]and Oxford was divided into 48 tracts with an average population of 2,645 each.[14]TheRegistrar General,however, opted for enumeration districts containing less than 1,000 people on average, rather than adopting census tracts.[13]While tracts composed of enumeration districts were later developed, these were not extensively used.[15]Census tracts have, however, been constructed and used by British demographers.[16]TheOffice for National Statisticsnow uses enumeration districts only for the collection of data, with output areas used as the base unit in census releases.[17]

United States

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See also:List of boroughs and census areas in Alaska

The concept of the census tract was first developed in the United States. In 1906, Walter Laidlaw originated the concept of permanent, small geographic areas as a framework for studying change from one decennialUnited States Censusto another in neighborhoods withinNew York City.[18]For the1910 Census,eight cities—New York,Baltimore,Boston,Chicago,Cleveland,Philadelphia,Pittsburgh,andSt. Louis—delineated census tracts (then termed ‘‘districts’’) for the first time. No additional jurisdictions delineated census tracts until just prior to the1930 Census,when an additional ten cities chose to do so. The increased interest in census tracts for the 1930 Census is attributed to the promotional efforts of Howard Whipple Green, who was a statistician in Cleveland,Ohio,and later the chairman of the American Statistical Association's Committee on Census Enumeration Areas. For more than 25 years, Green strongly encouraged local citizens, via committees, to establish census tracts and other census statistical geographic areas. The committees created by local citizens were known as Census Tract Committees, later called Census Statistical Areas Committees.

After 1930, the Census Bureau saw the need to standardize the delineation, review, and updating of census tracts and published the first set of census tract criteria in 1934. The goal of the criteria has remained unchanged; that is, to assure comparability and data reliability through the standardization of the population thresholds for census tracts, as well as requiring that their boundaries follow specific types of geographic features that do not change frequently. The Census Bureau began publishing census tract data as part of its standard tabulations beginning with the1940 Census.Prior to that time, census tract data were published as special tabulations.

For the 1940 Census, the Census Bureau began publishing census block data for all cities with 50,000 or more people.Census blocknumbers were assigned, where possible, by census tract, but for those cities that had not yet delineated census tracts, ‘‘block areas’’ (called ‘‘block numbering areas’’ [BNAs] in later censuses) were created to assign census block numbers. Starting with the1960 Census,theCensus Bureauassumed a greater role in promoting and coordinating the delineation, review, and update of census tracts. For the1980 Census,criteria for BNAs were changed to make them more comparable in size and shape to census tracts. For the1990 Census,all counties contained either census tracts or BNAs.

Census 2000was the first decade in which census tracts were defined in all counties. In addition, the Census Bureau increased the number of geographic areas whose boundaries could be used as census tract boundaries. It also allowed tribal governments of federally recognizedAmerican Indian tribeswith a reservation and/or off-reservation trust lands to delineate tracts without regard to State and/or county boundaries, provided the tribe had a 1990 Census population of at least 1,000.[19]

Census tracts are also used by theSmall Business Administrationto define boundaries ofHUBZones.

References

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  1. ^ab"Meshblock (Concept)".Statistics New Zealand.2 February 2016.
  2. ^ab"Census Tracts and Block Numbering Areas".U. S. Census Bureau. 2000-04-19.Retrieved2007-12-05.
  3. ^Domínguez-Berjón, Felícitas; Borrell, Carme; López, Rosario; Pastor, Vicente (2005)."Mortality and socioeconomic deprivation in census tracts of an urban setting in Southern Europe".Journal of Urban Health.82(2): 225–236.doi:10.1093/jurban/jti047.PMC3456560.PMID15888637.
  4. ^"U.S. Census Bureau definition".Archived fromthe originalon 2017-05-13.Retrieved2017-10-19.
  5. ^IBGE."IBGE | censo 2010 | materiais | guia do Censo | operação censitária".censo2010.ibge.gov.br(in Brazilian Portuguese).Retrieved2018-06-01.
  6. ^abc"IRIS. DEFINITIONS. Publication date: 13/10/2016".INSEE.Retrieved2022-05-13.
  7. ^"IRIS. DÉFINITIONS. Date de publication: 13/10/2016".INSEE.Retrieved2022-05-13.
  8. ^Seanad Éireann (17 June 1993)."Statistics Bill, 1993: Second Stage".Seanad Éireann debates.Houses of the Oireachtas.Retrieved8 January2019.
  9. ^abc"Small Areas Ungeneralised".data.gov.ie.Ireland. 2015. Archived fromthe originalon 8 January 2019.Retrieved8 January2019.
  10. ^abc"Census 2016 Small Area Population Statistics".Ireland: Central Statistics Office.Retrieved8 January2019.
  11. ^"2006 Census Enumeration Areas Boundaries".Central Statistics Office.Ireland.Retrieved8 January2019.
  12. ^"Census Reports 1821-2006".Central Statistics Office.Ireland.Retrieved8 January2019.
  13. ^abLongley, Paul; Clarke, Graham (1996).GIS for Business and Service Planning.New York: John Wiley & Sons. pp.80–81.ISBN0-470-23510-1.
  14. ^Robson, Brian Turnbull (1969).Urban Analysis: A Study of City Structure with Special Reference to Sunderland.Cambridge: Cambridge University Press. pp.44.ISBN0-521-07272-7.
  15. ^Exeter, Daniel J.; Boyle, Paul; Feng, Zhiqiang; Flowerdew, Robin; Schierloh, Nick (2005)."The creation of 'Consistent Areas Through Time' (CATTs) in Scotland, 1981–2001"(PDF).Population Trends.119:28–36. Archived fromthe original(PDF)on 2011-06-05.Retrieved2009-10-25.
  16. ^"Tracts – Information page".Social and Spatial Inequalities Group, Department of Geography,University of Sheffield.Archived fromthe originalon 2009-02-25.Retrieved2009-10-25.
  17. ^"Beginners' guide to UK geography: Census geography".Office for National Statistics. 2007-10-30. Archived fromthe originalon 2011-06-04.Retrieved2009-10-25.
  18. ^Krieger, Nancy (2006)."A century of census tracts: Health & the body politic (1906–2006)".Journal of Urban Health.83(3): 355–361.doi:10.1007/s11524-006-9040-y.PMC2527201.PMID16739037.
  19. ^"Census Tract Program for the 2010 Decennial Census—Final Criteria"(PDF).Federal Register.U. S. Census Bureau. 2008-05-14.Retrieved2008-10-14.
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