Understanding Census Geography Lisa Neidert NPC Workshop: Analyzing Poverty and Socioeconomic Trends Using the American Community Survey June 23 – June 27, 2008
Census Geography
2006 Geographic Areas
Geographic Areas ACS (2006)...
What’s available in the ACS: via maps Maps showing counties and places s/users_guide/2006_maps_for_counties _places.htm s/users_guide/2006_maps_for_counties _places.htm
Almost all counties: DE, MD, MA
Few counties, no places: VT and WY
State with American Indian Places: AK, AL, LA, NC, OK
What’s available in the ACS 2006: via Look-up table: Geographic entities available for ACS (2006) group/34a72eab-daa4-4d14-80e aed6c/Assignments/ACS2006_ Geographies.xls group/34a72eab-daa4-4d14-80e aed6c/Assignments/ACS2006_ Geographies.xls
Not ready for prime-time: census tracts and zip codes Need 5-year estimates file 2005 – 2009 Available 2010 Annual updates thereafter 2006 – – 2011, etc. Test site available – selected counties (34) Selected profiles (demographic, social, economic, housing) s/overview.html#noteforusers s/overview.html#noteforusers
Example Census Tracts for community districts
Community District 11: Manhattan, East Harlem
Zip codes Not census geography However, big demand for zip code data Census Bureau builds ZCTAs via census blocks ZCTA FAQs html Fun resource
What are PUMAs? Public Use Microdata areas Combination of population geographies that sum to at least 100,000 population. In rural areas, several counties will form a PUMA. In an urban area, a county will be subdivided into multiple PUMAs. PUMAs do not cross state boundaries
PUMAs.... PUMAs do not have good comparability over time (1990, 2000). PUMA geographies for the ACS are the same as the 2000 boundaries PUMAs are reasonable substitutes for counties Smallest geography available in the microdata.
PUMAs via Maps Reasonable tool for rural parts of a state Somewhat unwieldy for urban areas Multiple maps per state html
PUMAs via text Describes PUMA composition By: County County subdivision Place Census tract /SUPERPUMA pct.html /SUPERPUMA pct.html
Metropolitan areas Defined by Office Management Budget (OMB) es/metrodef.html es/metrodef.html Historical Definitions es/pastmetro.html es/pastmetro.html Researcher is free to follow own definitions Census Bureau follows OMB definitions