What’s available in the ACS for single year data: via maps Maps showing counties and places for each state (or the nation) http://www.census.gov/acs/www/Product s/users_guide/acs_2008_reference_map s.htm http://www.census.gov/acs/www/Product s/users_guide/acs_2008_reference_map s.htm
States where all counties are over 20,000 Connecticut Delaware District of Columbia New Hampshire New Jersey Rhode Island
What geographies are available in the 2006-2008 ACS? http://www.census.gov/acs/www/acs-php/2006_2008_beginner_users_guide.php
What’s available in the ACS: via Look-up tables Geographic entities available for 1-year data (2007) Geographic entities available for 1-year data (2007) Geographic entities available for 3-year data (2005-2007) Geographic entities available for 3-year data (2005-2007)
Not ready for prime-time: census tracts and zip codes Need 5-year estimates file 2005 – 2009 Available 2010 Annual updates thereafter 2006 – 2010 2007 – 2011, etc.
Zip codes Not census geography However, big demand for zip code data Census Bureau builds ZCTAs via census blocks ZCTA FAQs http://www.census.gov/geo/ZCTA/zctafaq. html Fun resource http://en.wikipedia.org/wiki/Zip_code
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... Can be valuable for bypassing geographic restrictions when one wants national information at the county level Create pseudo counties based on a cross-walk between PUMAs and counties
Statistics based on 1-year ACS data Unit is county
Statistics based on 3-year ACS data Unit is county
Statistics based on 1-year ACS data Unit is PUMA
PUMAs via Maps Reasonable tool for rural parts of a state Somewhat unwieldy for urban areas Multiple maps per state http://usa.ipums.org/usa/volii/2000pumas.shtml
PUMAs via text Describes PUMA composition By: County County subdivision Place Census tract http://usa.ipums.org/usa/volii/2000pumas.shtml http://usa.ipums.org/usa/volii/2000pumas.shtml
Metropolitan areas Defined by Office Management Budget (OMB) http://www.census.gov/population/www/estimat es/metrodef.html http://www.census.gov/population/www/estimat es/metrodef.html Frey, et. al. “Field Guide” http://www.psc.isr.umich.edu/dis/census/brooki ngs.pdf http://www.psc.isr.umich.edu/dis/census/brooki ngs.pdf Users are free to follow own definitions Census Bureau follows OMB definitions