Lewis Mumford Center

  Updates and Technical Notes

Updates
  • 10/27/03. Completed integrated "Metro and City Info" webpages. The integrated pages allow a user to access any information the Mumford Center has for cities, states, or metropolitan areas from a single page. Links to Mumford Center reports and news articles written about Mumford Center projects are also available on the integrated webpages.
  • 10/21/03. Updated the "Homeowners and Renters" using adjusted SF2 data. To overcome data suppression applied by the Census, the Mumford Center developed a procedure to fill in missing values. A detailed technical note outlining the procedure employed by the Mumford Center is available here.
  • 9/15/03. Completed "Occupational Change: Metropolitan America, 1990-2000" webpages.These pages provide 1990 Census occupation number employed converted to their equivalent Census 2000 categories for a consistently defined 2000 metropolitan region geography. For comparison, we also provide the conversion counts for metropolitan regions under their 1990 geographic definitions (as available from the Census Bureau's American FactFinder web site).
  • 9/01/03. Released report:"Segregation in Neighborhoods and Schools: Impacts in Minority Children in the Boston Region." Prepared for presentation at the Harvard Color Lines Conference, this report describes residential patterns and their consequences for school segregation and school inequality using data from the 2000 census and 1999-2000 school year.
  • 8/15/03. Updated "The Muslim World in Metropolitan America" (released:10/07/02) and "Black Diversity in Metropolitan America" (released: 2/17/03) using extractions from the Census 2000 1% Public Use Microdata Sample (2000 PUMS). Although the C2SS (original data source) and 2000 PUMS are weighted samples, the 2000 PUMS is larger (a 1-in-100 national random sample) than the C2SS (a 1-in-750 national sample drawn from 1203 counties) and thus provides more accurate population estimates. For a more detailed description of these data sources please refer to the technical documentation available at the Census website (www.census.gov).
  • 2/27/03. Completed update to the "Separate and Unequal" and "Dimensions of Segregation" web pages, including information for all cities with populations greater than 10,000. These data are available for 1990 and 2000, not adjusting for changes in city boundaries over time.
  • 2/27/03. Completed update to the "Segregation - Children (under 18)," "Homeowners and Renters," "The New Americans," State of the Cities," "Separate and Unequal," "Diversity in Black and White," web pages, using corrected metro boundaries for 1990. The changes are slight, and there were no changes in most metro areas.
  • 12/20/02. Added information to the "Segregation: whole population" web pages. 1) Added population counts and segregation indices for cities with populations greater than 10,000. These data are available for 1980, 1990 and 2000, not adjusting for changes in city boundaries over time. 2) Added the 2000 "adjusted" census counts (released by the Census Bureau in December 2002) for total population and for each major racial/ethnic group (for individual cities, as well as metro areas).
  • 11/19/02. Released "Technical Report: Comparability of the 2000 and 1990 Census Occupation Codes." Using this crosswalk, analysts will know which detailed occupation categories in 1990 and 2000 can be combined to create a consistent management/professional category.
  • 11/6/02. Added new set of web pages based on SF3 tract data: "Dimensions of Segregation." These pages provide measures of segregation between households with different incomes, between immigrants and natives, as well as measures of racial segregation controlling for income or nativity.
  • 11/5/02. Updated the "Segregation - whole population" web pages, using corrected metro and central city boundaries for 1990. In a few cases, these are significant changes.
  • 10/15/02. Released 12th report: "Separate and Unequal: The Neighborhood Gap for Blacks and Hispanics in Metropolitan America." Based on SF3 tract data (and comparable data for 1990), this report points out the continuing income disparities among races and the increasing disparities in the quality of their neighborhoods. It demonstrates that affluent minorities experience as large a neighborhood gap as do poor minority households.
  • 10/7/02. Released revision and update of the "Muslim World in Metropolitan America" report, including information from SF3 tract data showing the numbers and locations of people with origins in predominantly Muslim countries. The report also uses data from the Census 2000 Supplemental Survey to show the relatively high economic and educational profile of this population.
  • 10/1/02. Completed two sets of web pages based on SF3 tract data."Separate and Unequal" provides information on group differences in income and nativity, and examines their effects on neighborhood inequalities."Diversity in Black and White" provides information on the size and neighborhood locations of white and black subgroups: European white ancestry groups, people with birth or ancestry in predominantly Muslim countries, and blacks with African birthplaces or Afro-Caribbean ancestry. NOTE: These pages include corrections in our procedure to match the 1990 and 2000 geography of some cities and metropolitan regions. Corrections to other data sets are in progress.
  • 6/24/02. Released 11th report: "The Suburban Advantage." Based again on the SF3 Profiles, the report shows large and generally increasing economic disparities between cities and suburbs, although in a few places (like Chicago and Seattle) cities began to catch up with their suburbs.
  • 6/19/02. Added sortable lists and downloadable data files for metro area SF3 Profiles.
  • 6/5/02. Released 10th report: "Regional Divisions Dampen '90s Prosperity: New Census Data Show Economic Gains Vary by Region." Based on the SF3 Profiles of Census 2000, this report documents the rebound of the Rustbelt since 1990, continued catching up by metro areas in the South, and relative stagnation or decline in the Northeast and Southern California.
  • 5/20/02. Added two sets of web pages to report information from the SF3 Profiles as they were released by the Census Bureau: "State of the Cities" and "New Americans."
  • 5/8/02. Released ninth report: "Hispanic Populations and Their Residential Patterns in the Metropolis." This report analyzes differences in the residential patterns of people from specific Hispanic national origins, trends in segregation and formation of distinctive Hispanic enclaves in the metropolis.
  • 3/28/02. Issued revised school segregation report. The revised report is based on data on children in elementary grades, regardless of the grade range of their school. Added web pages to report information for several thousand school district for 1989-1990 and 1999-2000.
  • 12/18/01. Released eighth report: "Choosing Segregation: Racial Imbalance in American Public Schools, 1990-2000." This report was based on data on elementary schools (defined as schools beginning in pre-K or K) from the National Center for Education Statistics. Added web pages to report information by metropolitan region and by school district for 1989-1990 and 1999-2000.
  • 11/19/01. Released seventh report: "The Muslim World in the United States," based on data from the 1990 Census of Population and the pooled 1998-2000 samples of the Current Population Survey.
  • 11/19/01. Released sixth report: "From Many Shores: Asians in Census 2000," based on data from the 1990 and 2000 Census of Population, and nativity and socioeconomic data from the pooled 1998-2000 samples of the Current Population Survey. Added information on Asian national-origin population counts for states and individual metropolitan regions (1990 and 2000) to the website.
  • 11/9/01. Issued corrected population counts and segregation indices for the under-18 population in 1990. In several large metro areas with substantial minority populations, the new indices reveal higher segregation of children in 1990 than previously reported. Files downloaded before this time should be updated.
  • 10/26/01. Added 1980 data to the website and downloadable files. Corrected estimates of segregation for 1990, using STF1A full-count tract data in place of STF3A sample data; this has a large effect in metro areas with small minority populations.
  • 9/10/01. Released fifth report: "The New Latinos: Who They Are, Where They Are" to replace "Immigrant Enclaves in the American Metropolis." Added estimates of the size of specific Hispanic national-origin groups to the website.
  • 7/9/01. Released fourth report: "The New Ethnic Enclaves in America's Suburbs."
  • 9/6/01. Second geographic adjustment, using census tract equivalency files as a method of maintaining constant 2000 metropolitan, city, and suburb designations.
  • 7/5/01. Website redesigned to accommodate release of additional types of data and reports. Released third report based on preliminary analyses: "Immigrant Enclaves in the American Metropolis."
  • 5/6/01. Children segregation data added to the site, with an accompanying report: "Living Separately: Segregation Rises for Children."
  • 4/3/01. Released first report: "Ethnic Diversity Grows, Neighborhood Integration Is at a Standstill."
  • 3/30/01. First geographic adjustment, using 2000 metropolitan and city/suburb boundaries for 1990 data.
  • 3/11/01. Census website received its first visitors.

Technical Notes
  1. The 2000 Census is the first to allow respondents to list up to four different racial/ethnic categories to describe themselves. There was also a separate question about Hispanic origin. This allows for numerous ways of categorizing individuals into racial and ethnic groups. Our purpose has been to identify categories on non-Hispanic white, non-Hispanic black, Hispanic, and Asian, as similar as possible to the way those categories were defined in the 1990 Census.

    Coding for 1980 and 1990 is as follows. All Hispanics are included in the Hispanic category, regardless of race. Asians and Pacific Islanders are reported as a single category by the census. Hispanic Asians are included in both the Hispanic count and the Asian count. This is because the STF4 files in 1980 and 1990, which allow analysts to introduce information such as income and education into studies of racial groups, also include Hispanic Asians in the tables both for Hispanics and for Asians. Because there are few Hispanic Asians, this choice has little practical importance.

    Coding for 2000 is much more complicated. Our procedure has undergone some adjustments over time. As a result of variations in how Census 2000 treats race in various tabulations that we rely on, we use slightly different definitions on different web pages.

    On all pages, we use the following rules for classifying "Hispanic" and "non-Hispanic white" in 2000:

    • We code as "Hispanic" any person listed as Spanish/Hispanic/Latino, regardless of what they answered for the race/ethnicity question.
    • We code as "non-Hispanic white" non-Hispanics who answered only "white" as their race.

    The data provided on the "Segregation-Whole Population" and "Segregation-Children (under 18)" classify "non-Hispanic black" and "Asian" for 2000 as follows:

    • We code as "non-Hispanic black" any non-Hispanic who indicated that they were Black or African-American, regardless of any other race/ethnicity they may have indicated.
    • We code as "Asian" any remaining non-Hispanic (individuals not already classified as non-Hispanic white or non-Hispanic black) who indicated that they were Asian or Pacific Islander, regardless of any other race/ethnicity they may have indicated.

    On all other pages, we define non-Hispanic black and Asian for 2000 as follows:

    • We code as "non-Hispanic black" any non-Hispanic, non-Asian who indicated that they were Black or African-American. This means that "black Asians" are not counted as black.
    • We code as "Asian" anyone who indicated that they were Asian alone, or in combination with one or more races, and with one or more Asian categories.

    The treatment of Asians in these other web pages introduces several changes from the definition used in the "Segregation-Whole Population" and "Segregation-Children (under 18)" pages:

    • Pacific Islanders are not included (unless they also reported being Asian).
    • People who reported two different Asian ethnicities (e.g. Japanese and Filipino) are double-counted.
    • Hispanic Asians are counted as Asian and also as Hispanic.


  2. Data from Census 2000 are from the full-count PL-794 and SF1 files. Initially the 1990 population counts and segregation indices were calculated from tract-level data from STF3A, which is based on the long-form sample. In October 2001 we discovered that there are large discrepancies in segregation indices between sample data and full-count data in metro areas where the minority population is less than 1-2% of the total. We now rely entirely on full-count data.


  3. In order to differentiate between central city and suburban census tracts, we used data from the "split tract" summary level for all of our calculations. Tracts are "split" when they straddle place boundaries. In the 2000 data, some tracts also straddle voting district boundaries. These units have been aggregated in order to maintain comparable tract sizes, and number of tracts, across years.


  4. The 2000 census data are now based on the new metropolitan boundaries for 2000. In order to maintain comparability across years, we have re-configured the 1980 and 1990 metropolitan boundaries to match those of 2000. We also followed the most recent definition of central cities. Using this method, we were able to link all metro areas for 1990 and 2000. For 1980, some small metropolitan regions cannot be included, because their territory had not been tracted.

    The geography for this website, including downloadable data files, has varied over time:

    1. Initially the 1990 data were based on 1990 metropolitan boundaries and city/suburb classifications.

    2. A geographic adjustment on 3/30/01 brought 1990 data into line with 2000 boundaries. We used FIPS place codes to determine which tracts should be located in each metropolitan area. One shortcoming of this method is that places with a population of less than 10,000 cannot be identified. In these cases, tracts were assigned to their original 1990 msa/pmsa location. The same method was used to determine whether a tract was located in a central city or a suburb.

    3. A second geographic adjustment on 9/6/01 used tract equivalency files from the Bureau of the Census to attach the 2000 metropolitan area code to each tract in 1980 and 1990. We view this as the optimal method of constructing 2000 metropolitan boundaries in 1990, and it is limited in 1980 only to the extent that some areas were untracted. Some tracts that were split across place boundaries in 2000 could not be precisely linked to an equivalent split tracts in 1980 or 1990, so we could not use their 2000 central city or suburb designation for them. Where all portions of the tract were in city or suburban places, this posed no problem. In cases where part of the tract was central city and part was suburban in 2000 (such tracts include 1.42% of the 1990 metropolitan population), we assigned the earlier year's designation to it.


    The following links provide definitions of the components of metropolitan areas as established by the Office of Management and Budget.

    • Click here to view a list of the counties contained within each metropolitan area.
    • Click here to view a list of the central cities contained within each metropolitan area.


  5. You must enable java in your browser's preferences in order to view the full content of this site. If java is not enabled, you will not see the pie charts on the metropolitan area data pages.


  6. The following formulas were used to generate segregation scores. The examples give here are for white/black indices, but the same formulas may be used for all combinations of groups.


    Where:
       B = the metropolitan black population
       Bi = the black population of tract i
       W = the metropolitan white population
       Wi = the white population of tract i


    Where:
       B = the metropolitan black population
       Bi = the black population of tract i
       Ti = the total population of tract i

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