Harvard Government 90dn Lecture 4

Government 90dn Mapping the Census Lecture 4: Geographical Units

Sumeeta Srinivasan [email protected]

Outline for Today ƒ ƒ ƒ

Geographical Units in Census How to compare across time/ space Discussion

Major Units: Blocks, Census Blocks, Tracts Source: http://www.census.gov/geo/www/geo_defn.html

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Blocks, Block groups, tracts do not cross the boundaries of any entity for which the U.S. Census Bureau tabulates Tabulation blocks are identified uniquely within census tract and block groups Census 2000 collection blocks, block groups and tracts are numbered uniquely within county (or statistically equivalent entity)

Major Units: Counties Source: http://www.census.gov/geo/www/geo_defn.html

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The primary legal divisions of most states are termed counties. In Louisiana, these divisions are known as "parishes" In Alaska, statistically equivalent entities are organized boroughs and the census areas Maryland, Missouri, Nevada, and Virginia have one or more incorporated places that are independent cities DC is one county

Major Units: County subdivisions Source: http://www.census.gov/geo/www/geo_defn.html

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Census county divisions CCD, census subareas, minor civil divisions MCD, and unorganized territories The boundaries of CCD, MCD etc. follow visible features, and coincide with census tracts where applicable CCD delineated by Census – 21 states (includes Alabama) MCDs are the governmental or administrative divisions of a county in 28 states (includes Mass.)

Counties and County Subdivisions

Major Units: Metropolitan Areas Source: http://www.census.gov/geo/www/geo_defn.html

Concept of a metropolitan area (MA): large population nucleus, with communities that have economic/ social integration Each MA must contain a place with minimum population 50,000 or a U.S. Census Bureau-defined urbanized area An MA contains one or more central counties (with specified level of commuting) Classified as:

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Metropolitan statistical area (MSA) or Consolidated metropolitan statistical area (CMSA) divided into primary MSA (PMSAs)

If MA has more than 1 million people 2 or more PMSAs may be defined

Metropolitan Areas ƒ

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Each MSA, PMSA and CMSA was assigned a unique 4-digit FIPS code, inherited usually from Standard Metropolitan Statistical Areas SMSA of the same or similar name in previous Census. For Massachusetts:

Major Units: Places Source: http://www.census.gov/geo/www/geo_defn.html

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Place is a concentration of population Include census designated places CDP, consolidated cities, and incorporated place CDPs are delineated to provide data for population that are identifiable by name but are not legally incorporated A consolidated city is a unit for which the functions of an incorporated place and its county or MCD merged An incorporated place is established for governmental functions for a concentration of people as opposed to a MCD created to provide services or administer an area without regard to population

Places

Major Units: Urban or Rural Source: http://www.census.gov/geo/www/geo_defn.html

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U.S. Census classifies as urban all territory, population, and housing units located within an urbanized area (UA) or an urban cluster (UC) An urban cluster (UC) consists of densely settled territory that has at least 2,500 people but fewer than 50,000 people An urbanized area (UA) consists of densely settled territory that contains 50,000 or more people. A UA may contain both place and nonplace territory

UA and UC ƒ

For Massachusetts:

Comparing across geographic unit and time ƒ Across time: http://mcdc2.missouri.edu/websas/geocorr2k.ht ml ƒ Across unit: http://www.census.gov/popest/geographic/bound ary_changes/