Dissemination of U.S. Census Data and Results: The role of ICPSR First Conference of Al-Khawarezmi Committee on Statistics Doha, Qatar 6-8 December 2010

U.S. CENSUS DATA – 2010: KEY DATES National Census Day: 1 April 2010 April - July 2010: Census takers visit households that did not return a form by mail December 2010: By law, the Census Bureau delivers population information to the President for apportionment March 2011: By law, the Census Bureau completes delivery of redistricting data to states

U.S. CENSUS DATA – 2010: DISSEMINATION OF RESULTS American FactFinder (AFF) is an online source for population, housing, economic and geographic data that presents the results from four key data programs:  Decennial Census of Housing and Population and 2000  Economic Census  American Community Survey 1-Year Estimates and 3-Year Estimates  Population Estimates Program - July 1, 2006 to July 1, 2009 Results from each of these data programs are provided in the form of data sets, tables, thematic maps, and reference maps.

U.S. CENSUS DATA – 2010: DISSEMINATION OF DATA Direct File Access through Download FTP Center at Census Bureau Free Access to all PUBLIC-USE DATA FILES First Release of Data: – 2010 Census Redistricting Data Summary File: State population counts for race and Hispanic or Latino categories State housing unit counts by occupancy status (occupied units, vacant units) Other Important Files: – Summary files with population counts and housing characteristics for many detailed race categories – Public Use Microdata (PUMS) Files with information on age, sex, race, household type and relationship, and tenure data with identifying information removed derived from geographic areas in excess of 100,000 people

U.S. CENSUS DATA: DISSEMINATION OF DATA AND ICPSR Another access point, focused on the social science research community, to Census data and documentation Original Census data available from the 1960s onward as well as special samples created for earlier years TIGER Line Files American Community Survey Many of the newer files are available in a variety of formats: SAS SPSS Stata Ascii text files Tab-delimited

The Decennial In(di)gestion Census Data: Collected regularly since the 1960s. Number of files and bytes have grown exponentially with every new Census. Main reason for the rapid growth in the numbers of data files archived and disseminated by ICPSR. How much and how rapid?

The Decennial In(di)gestion

Cooperative Agreements Close collaboration with the Bureau over the years in making data available to the academic research community. Since the 1980’s ICPSR has sought outside funding to deal with Census data and entered into joint statistical agreements with the Bureau to facilitate its distribution and use. Importance in 1990: High cost of raw data ($175 per reel of tape; entire Census comprised about 2000 tapes = C. $350,000).

Cooperative Agreements Data available to at no cost to member institutions without any rights to redistribute or resell. Joint annual summer workshops to offer training on the new Census data products. One week training sessions held in and Census Bureau staff participated extensively in these courses Attracted both researchers and ICPSR Official Representatives who attended to learn how to provide assistance to faculty and students on their campuses

Special Census Subsets These files report population and housing data for national and specific sub-national geographical entities, for example: – The entire nation – Each individual state – Counties – Metropolitan Areas – Places – Census Tracts

Contextual File Based largely on Census data Provides information at the ‘county’ level in the U.S. (subunits of states numbering more than 3,100 in all) Contains data from other government and private sources at the same geographic level Under certain circumstances, can be merged with survey data

Contextual File - 2 P opulation by age, sex, race, and Hispanic origin Labor force size and unemployment Personal income Earnings and employment by industry Land surface form typography Climate Government revenue and expenditures Crimes reported to police Presidential election results Housing authorized by building permits Medicare enrollment Health profession shortage areas

Preservation ICPSR provides another location to preserve data and documentation files produced by the Census Bureau ICPSR keeps multiple copies of these files both at its home location at the University of Michigan and at other sites in the United States Copies are continually checked and updated when necessary Considerable interest in historical Census data by demographers, historians, and economists.