The Decennial U'S' Census

1
The Decennial U.S. Census

• Brief History and Introduction

2
Decennial Population Census

• Begun in 1790 to determine representation and
  taxation
• Six questions on the first survey
• First inquiries on another topic, manufacturing,
  were made in 1810
• 1820 Census asked more in-depth population
  questions

3
Decennial Census (contd.)

• Other censuses added to the population census
• Agriculture, Mining, Governments, Religious
  Bodies (discontinued after 1936), Business,
  Housing, and Transportation adding e-commerce
  survey and detail on service sectors
• Legislation (1948 and later) specified that the
  various economic, agriculture, and government
  censuses be taken at separate times than
  population and housing censuses
• 2000 Census first in which primary medium is
  electronic

4
Logic of the Data Releases

• Public Law (P.L.) data data necessary for
  voting district configuration
• over 18 total population race
• Summary File 1 Short form data (100)
• Summary File 3 Long form data (sample)

5
Content of the Data Releases

• P.L. Data
• Population, total and over 18 (voting)
• Race and ethnicity

• SF1
• Age sex
• Race ethnicity
• Household relationships
• Housing units tenure data vacancy
  characteristics
• Group quarters data
• Urban/rural

6
Content of the Data Releases

• SF3 Population
• Age (cross-tab)
• Race ethnicity (cross-tab)
• Marital Status
• Employment Income
• Language spoken at home, ancestry migration
• Military service
• Farm residence
• Disability
• Grandparents as caregivers
• School enrollment educational attainment

• SF3 Housing
• Heating fuel fuel cost
• Number of rooms bedrooms
• Occupation, industry, class of worker work
  status in 1999
• Year structure built units in structure
• Telephone service
• Plumbing kitchen facilities
• Utilities, mortgage, taxes, insurance
• Value of home/monthly rent paid
• Vehicles available
• Year moved into residence

7
Future of the Census American Community Survey
(ACS)

• Will replace the long form and provide data every
  year
• but as a multi-year average for geographies with
  less than 65,000 people
• Began in 2004 and in full operation by 2010
• Will sample 3 million households annually

8
American Community Survey

• Rolling survey of certain number each month with
  telephone and personal followups
• 2005 incls data for areas of 65,000 (every
  year)
• 2007 incls data for areas of 20,000 65,000
  (3-year aver.)
• 2009 incls data for areas smaller than 20,000
  (5-year aver.)
• More information at http//www.census.gov/acs/www/
  
• Data available through American FactFinder at
  http//factfinder.census.gov

9
Census GeographyAn Abbreviated Hierarchy
AIANHH

• Nation

State
ZCTA 3- and 5-digit summary levels
Cong. District
County
Place (Muncipalities CDPs)
Cnty Subdivision (Township)
Census Tract
Block Group
Block
AIANHH - American Indian/Alaskan Native/Hawaiian
Homelander CDP - Census Designated Place ZCTA -
Zip Code Tabulation Areanever to be confused
with a Zip Code
10
Zip Code Tabulation Areas

• Only roughly comparable to actual zip codes
• No corporate/institutional zip codes
• Some P.O. box codes included
• Total area coverage, land water
• HH fresh water
• XX salt water
• Better off with ESRIs zip code layer if need
  current boundaries

11
Important Distinctions

• Race versus Ethnicity
• Household versus Family
• Metropolitan versus Urban

12
Primary Resources for GIS Census Data

• Search http//www.lib.ncsu.edu/gis/ for Census
• Lots of existing layers with Census attributes
• Most common geographic levels
• If cant find variables you need there

13
Primary Resources for GIS Census Data

• GeoLytics discs
• NR Library or D. H. Hill
• Georeferenced and easily downloaded in shape file
  format
• 1970 through 2000 data available
• Quirky DOS program may encounter errors
• No ACS data

• American FactFinder
• http//factfinder.census.gov
• Not georeferenced must be joined to a GIS layer
• 1990, 2000 decennial data and ACS data
• 2000 data has Geo within Geo option
• 20-minute limit

14
Online Resources

• Starting Guide to Census Resources
• http//www.lib.ncsu.edu/data/cendata.html
• User Guide for GeoLytics Resources
• http//www.lib.ncsu.edu/data/giscensusdata.html