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