Issues in Housing: Investigating a Census Tract

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Census Tract Data

What is a census tract?

A census tract is a small statistical subdivision of a county. Census tract data allows a user to find population and housing statistics from the decennial census about a specific part of an urban area. This is particularly important when you want information about part of a city (such as Northridge or other communities which are part of the City of Los Angeles). A single community may be composed of several census tracts. Always determine the boundaries of a census tract as they usually differ from the boundaries of communities within the city, the boundaries used for neighborhood councils, and zip code boundaries.

How to find census tract data

Use Finding Census Tract Data on the Internet, an online guide with detailed instructions on how to find data at the census tract level in the 2000 Census of Population and Housing and/or the 1990 Census of Population and Housing using the Census Bureau's American Factfinder database.

1. Find Your Tract Number and View a Map of the Tract, including how to find a Fact Sheet about a specific tract and a map showing the tract's boundaries.
2. Finding the Data using American Factfinder's Data Sets. Follow the directions on using American Factfinder to access all the Census 2000 data about the population and housing characteristics of the census tract. (This gives you more information than a Fact Sheet has about a specific tract).

What topics were included in the census?

• Census Overview and Census Questionnaires (2000 and 1990)
• American Factfinder: Fact Sheets vs. Data Sets
  • Fact Sheets are quick and easy and include lots of data. However, there is additional information available if you use Data Sets. (Example: the number of people living in nursing homes and the number of unmarried-partner households by sex of partners both can be found using the data set Summary File 1). So, some people doing this assignment may want to use both Fact Sheets and Census 2000 data sets (usually Summary File 1 and Summary File 3).
  • Differences between data sets
    • Census 2000 Summary File 1 and Summary File 2 focus on shortform (100 per cent) subjects: Age, Hispanic or Latino Origin, Race, Sex, Household Relationship, and whether Homeowners or Renters.
    • Census 2000 Summary File 3 and Summary File 4 focus on longform (i.e. sample data) subjects, i.e.: Ancestry, Citizenship, Disability, Educational Attainment, Income, Industry, Language Spoken at Home, Marital Status, Migration, Occupation, Place of Birth, Place of Work, Poverty, Rent, School Enrollment, Tenure, and Units in Structure. Note that Summary File 3 and Summary File 4 data are based on a sample and hence may be less exact for small areas and small groups than data in Summary File 1 or Summary File 2.
    • Summary File 2 and Summary File 4 enable the user to get data broken down by more detailed ethnic group/race. Be sure to read about the thresholds if you choose either Summary File 2 and Summary File 4.
    • American Factfinder also includes 1990 Census data sets.

Definitions of terminology used in the 2000 Census are in:

• American Factfinder includes a Glossary (a link on the bar near the top of the page)
• Appendix B of the Summary File 1 Technical Documentation, for 100 per cent subjects (PDF; use Adobe Reader)
• Appendix B of the Summary File 3 Technical Documentation, for sample subjects (PDF)
• Racial and Ethnic Classifications Used in Census 2000 and Beyond

Helpful hints when using American Factfinder

• The Census Bureau advises users that pop-up blocker software may affect American Factfinder in unusual ways. So, if you use a pop-up blocker, make sure it is turned off when you use American Factfinder.
• Some tables produced by American Factfinder are too wide to print unless you change your printer settings from portrait to landscape.
• If you choose to email census data that you have found on your census tract, be sure to copy and paste the data into the email message. (Pay attention here: if you attach the page or use the quote function instead of using the copy/paste method, you may get a general page from the Census Bureau site instead of your customized results for a specific tract).
• If saving to a disc or USB Flash Drive/USB Stick, always check when done to be certain that you have a readable file that contains the data you intended to save.

Other Information Sources

Updating the Census

In the years between decennial censuses, various organizations produce estimates of demographic changes in American communities. The most reliable update is the Census Bureau's American Community Survey, released via American Factfinder. The American Community Survey is conducted annually, but the geographies do not go as small as census tract or zip code. American Community Survey 2005 data is available for cities with populations of more than 65,000, i.e., you can get American Community Survey 2005 data in American Factfinder for the entire City of Los Angeles, but not for specific tracts, communities, or zip codes within the city. Examples of online sources which provide estimates more recent than the census at the census tract level are:

• Demographic Research Unit Statistical Reports (City of Los Angeles Planning Department).
  • Local Statistics includes 2004 estimates at the census tract level for a small number of variables for census tracts within the City of Los Angeles. Estimates are also available for Area Planning Commissions, Community Plan Areas such as Chatsworth-Porter Ranch and Northridge, and City Council Districts.
  • Note: This site seems to work better with Internet Explorer.
• Residential Vacancy Data (City of Los Angeles Housing Department) provides information on idle residential water/electrical meters as an indicator of housing vacancies.
• FFIEC Census Reports (Federal Financial Institutions Examination Council) includes 2006 estimates of Tract Median Family Income.
  

Additional sources with Census 2000 tract-level data (i.e. these repackage data from the Census Bureau)

• Demographic Research Unit Statistical Reports (City of Los Angeles Planning Department).
  • Census 2000 on this site offers summaries of Census 2000 data totaled for subareas of the City of Los Angeles, including Area Planning Commissions, Community Plan Areas such as Chatsworth-Porter Ranch and Northridge, City Council Districts, and Census Tracts. The Census 2000 tables by Community Plan Area list the data by census tracts within (or partially within) the community plan area. (Note: San Fernando Valley Economic Research Center's SFVERC Census Data includes an Excel table with tract numbers whose boundaries are entirely within specific San Fernando Valley communities).
  • Archive of 1990 Census Data is also in the Census 2000 part of this site. It offers 1990 data by the boundaries of Census 2000 Tracts and 2002 City Council Districts.
• Interactive City Maps. Geographic Information System (GIS) application from the City of Los Angeles that offers land and property information, 2000 demographic information at the census tract level, flood zone information in a map form, and more.
• Neighborhood Knowledge Los Angeles (site about the City of Los Angeles)
  To use the LANews databases at the Knowledge Network Los Angeles site you must log in, create a password for yourself, and agree to the rules of the site. Then select Data & Maps. Data is provided on complaints filed with the Department of Building and Safety, residential contruction permits, Department of Water and Power liens, tax liens, etc. Some information is by ZIP code or census tract number, some is by Council district, some on a street name basis (you enter the street name and range of addresses on the street). Site offers a choice of English or Spanish language. You may also want to experiment with LA LOTS (Los Angeles Land Opportunities Tracking System), a related website.

Sources for information and maps by city planning area and/or zip code

By Planning Area or other city-specified format

• Cities often have planning areas that correspond to neighborhoods or communities within the city. The city's web site may include statistics, maps, and other information about the planning areas. Examples for the City of Los Angeles are:
  • Demographic Research Unit Statistical Reports (Los Angeles City Planning Department).
  • Los Angeles City General Plan and Los Angeles City Community Plans. Essential information on land use, including maps from the Los Angeles Department of City Planning. See also their Community Plan Profiles and Statistics. Be sure to examine the boundaries of the community in the planning area as they may or may not be the same as zip code boundaries for the community or other sets of boundaries that could be used to define the community. (Example: The Northridge Fashion Center mall is within the Post Office's zip code 91324, a zip code associated with Northridge, but the mall is located within the Chatsworth-Porter Ranch's planning area boundaries).
  • Los Angeles Neighborhood Council Maps. Note: Descriptions of the boundaries of each Neighborhood Council are also available as part of the Neighborhood Council Roster/Database.
• City departments often organize information in a way that reflects their administrative organization (example= police divisions) or the way they think will be most useful to the public.
  • Los Angeles Department of Parks and Recreation has a park location website.

By Zip Code

• Some information about communities within the city is accessible by zip code rather than census tract. Community Information by Zip Code provides an extensive list of population, education, health, environment, business, and political information sources that are searchable by zip code. Most of the information sources are text sources, but some create maps of data that are searchable by zip code. (Note: MABLE/Geocorr2K: Geographic Correspondence Engine with Census 2000 Geography allows you find out which census tracts--or parts of tracts--are associated with a specific zip code. American Factfinder can be used to create a Fact Sheet--with an accompanying map--for a zip code). This page's environment section, Environmental Information by Zip Code, includes (among others):
  • Where You Live/Search Your Community (Environmental Protection Agency). Environmental information searchable by Zip Code. Includes Enviromapper.
  • Toxics Release Inventory database.
  • TOXMAP Environmental Health e-Maps (National Library of Medicine)

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Created and maintained by Mary M. Finley
Questions or comments: mary.finley@csun.edu
Links checked: 19 January 2007

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