Transcript Understanding Census Geography Lisa Neidert NPC Workshop: Analyzing Poverty and Socioeconomic Trends Using the American Community Survey June 23 – June 27, 2008

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
 http://www.census.gov/acs/www/Product
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)
 https://ctools.umich.edu/access/content/
group/34a72eab-daa4-4d14-80e09150727aed6c/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 – 2010
 2007 – 2011, etc.
 Test site available
 – selected counties (34)
 Selected profiles (demographic, social, economic,
housing)
http://www.census.gov/acs/www/AdvMeth/Multi_Year_Estimate
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

http://www.census.gov/geo/ZCTA/zctafaq.h
tml
 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 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.s
html
PUMAs via text
 Describes PUMA composition
 By:




County
County subdivision
Place
Census tract
 http://usa.ipums.org/usa/volii/2000pumas.shtml
 http://www.psc.isr.umich.edu/dis/data/ref/PUMA
/SUPERPUMA-2000-5pct.html
Metropolitan areas
 Defined by Office Management Budget (OMB)
 http://www.census.gov/population/www/estimat
es/metrodef.html
 Historical Definitions
 http://www.census.gov/population/www/estimat
es/pastmetro.html
 Researcher is free to follow own definitions
 Census Bureau follows OMB definitions