Products Overview	Data Sources	General Information
Summary Files Public Use Micrdata Spatial Data	Files for FTP Online Extraction Data CD-ROM Products Spatial Data	Print and CDs at CU Other sources Comparing 1980 with other years Related Reference Material

Products Overview

Then lowest level of geography for summary data from 1970 is either block groups (in areas were tracts were defined) or enumeration districts (ED) elsewhere. This overview outlines how key products were originally published and highlights only a few of the custom products that were subsequently produced based on the original. The Data Sources section that follows focuses on the best available sources which may be products derived from the originals.

• Summary Files
  The table below outlines the most commonly used summary files from the 1970. Not all these files are readily available. For some that are, all states may not be reported. 1st and 2nd Count files are based on 100% counts while 4th and 5th Count data are sample data. Breakdowns within each of these files are shown below and are based on the geographic concept of "summary level." Summary level and other technical concepts pertaining to summary files are briefly described in the EDS guide, Census Summary Files: Technical Issues.

  First Count      1A: States and EDs      1B: States, counties, CCDs, MCDs, CDs	Fourth Count      4A: States-Tracts      4B: States-MCDs-CCDs      4C: States-MSA-Urban areas
  Second Count      1A: States and tracts      1AB: States, counties, CCDs, MCDs, CDs	Fifth Count      5A: 3 digit Zip Code      5B: 5 digit Zip Codes by SMSA      5C: States-Tracts-Block Group/EDs

  Some sample questions were asked of either a 15% or a 5% sample of households, but some were asked for both, thus constituting a 20% sample. Variation can occur among totals based responses from 20%, 15% or 5% samples.

 
• Other Summary File Products
  Special subsets based on either geography or topic have been created from the Summary Files. When needs can be met with these files, they are easier to use than the original files. Also there are the Elizabeth Bogue Census Tract Files for which data was keyed in from the printed tract reports for selected metropolitan areas.

 
• Public Use Microdata
  Public Use Microdata were produced and reported for county groups, states, and geographic divisions with neighborhood characteristics each with a population of at least 250,000. Originally the files were hierarchical (contain both household and person records). A modified version is also available that combines household and person data on record so that the file is rectangular.

 
• Maps and Geographic Products
  • Master Enumeration District List (MEDList)
    The MEDList files contain the names and codes for geographic areas used for reporting data in the summary files together with the population and housing counts for those areas. Geographic coordinates are reported for each enumeration district or block group. These files cannot be used directly by GIS software.
  • Maps
    Columbia's holdings for 1970 maps are described on the Government Documents 1970 Decennial Census Information web page.

Data Sources

• Files for FTP
  • ICPSR
    Provides the most complete archive of 1970 files including a number of special extractions produced by the Census Bureau for easier access for some geographic areas and the Elizabeth Bogue tract data files for selected metropolitan areas (does not include NYC).
  • DataGate
    Only a few selected files (especially for New York City counties) are stored locally. Search DataGate for study number 1970 to see what is available.

 
• Online Extraction Data
  • National Historical Geographic Information System (NHGIS)
    Provides an online extraction tool for selected summary file variables at the national, state, county, and tract/block numbering areas allowing for multiple locations at one level of geography to be downloaded at once. Downloads of a single area for other census geographies are available.
  • Integrated Public Use Microdata Series (IPUMS)
    At this site custom extractions of public use microdata can be done. Coverage is for all census years since 1850 except 1930.

 
• CD-ROM Products from Geolytics
  These products come with easy-to-use software that extract data for use in statistical packages, for making thematic maps, or for importing in to GIS software. Guides for using Geolytics software are available.
  • 1970 CensusCD+Maps
    This product, from Geolytics, runs on the EDS PC network. SF1 and SF3 data down to the tract level (no zip codes) are available.
  • Neighborhood Change Database
    Reports 1970 data using 2000 tract boundaries.

 
• Spatial Data
  
  • 1970 CensusCD+Maps
    Spatial files can be exported with data from this product.
  • National Historical Geographic Information System (NHGIS)
    NHGIS is a project to create and freely disseminate a database incorporating all available aggregate census information for the United States between 1790 and 2000. You can download tract boundary files by state

General Information

• Library's Collection
  This is a detailed list of Columbia's print and CD-ROM holdings plus links to useful Web sites and reference sources.
• Obtaining Data by Congressional District
• Historical Census Data Tables
  The Census Bureau has published a number of tables covering all census years. In addition to basic counts of people and housing, there are selected special topics included.
• National Archives and Records Administration (NARA)
  Together with listing of their electronic holdings (which are available at cost), the NARA provides descriptive information about each file.
• Comparing 1970 and with other Census years
  • Significant Changes to Counties: 1970-Present
    Summarizes the changes to boundaries for counties or county equivalent areas deemed to be significant because of either population affected or land area involved.
  • Tract Comparison Tables, New York City
    Excel spreadsheets that cover the tract changes between 1970-1980-1990-2000.
• Related Reference Material
  • Geographic Areas Reference Manual
    Although focused on the 1990 Census this book provides a history of census geography and includes information about areas like, MCDs, CCDs, outlying areas, indians lands, and blocks. This book is also available in print in EDS and in Lehman government collection (see CLIO).
  • Measuring America: The Decennial Censuses From 1790 to 2000
    Contains questionnaires and instructions, plus individual histories of each census as well as a chart listing topics covered in each census year. This book is also available in print in EDS and in CLIO.
  • Background Information About Census
    This site is part of the Historical Census Browser site and it provides a useful synopsis of the information found in the publication, 200 Years of Census Taking: Population and Housing Questions, 1790-1990. Washington, DC: Bureau of the Census, 1989 which is available in Lehman's U.S. government documents collection, call number, C 3.2:T 93.
  • Decennial Census Information General Census Monographs
    This is a list of other publication on the subject of the Decennial Census.