Introducing a new way to navigate by topics. Access the latest news, data, publications and more around topics of interest.
Our population statistics cover age, sex, race, Hispanic origin, migration, ancestry, language use, veterans, as well as population estimates and projections.
This section provides information on a range of educational topics, from educational attainment and school enrollment to school districts, costs and financing.
We measure the state of the nations workforce, including employment and unemployment levels, weeks and hours worked, occupations, and commuting.
Our statistics highlight trends in household and family composition, describe characteristics of the residents of housing units, and show how they are related.
Health statistics on insurance coverage, disability, fertility and other health issues are increasingly important in measuring the nation's overall well-being.
We measure the housing and construction industry, track homeownership rates, and produce statistics on the physical and financial characteristics of our homes.
The U.S. Census Bureau is the official source for U.S. export and import statistics and regulations governing the reporting of exports from the U.S.
The U.S. Census Bureau provides data for the Federal, state and local governments as well as voting, redistricting, apportionment and congressional affairs.
Search an alphabetical index of keywords and phrases to access Census Bureau statistics, publications, products, services, data, and data tools.
Geography provides the framework for Census Bureau survey design, sample selection, data collection, tabulation, and dissemination.
Geography is central to the work of the Bureau, providing the framework for survey design, sample selection, data collection, tabulation, and dissemination.
Find resources on how to use geographic data and products with statistical data, educational blog postings, and presentations.
The Geographic Support System Initiative will integrate improved address coverage, spatial feature updates, and enhanced quality assessment and measurement.
Work with interactive mapping tools from across the Census Bureau.
Find geographic data and products such as Shapefiles, KMLs, TIGERweb, boundary files, geographic relationship files, and reference and thematic maps.
Metropolitan and micropolitan areas are geographic entities used by Federal statistical agencies in collecting, tabulating, and publishing Federal statistics.
Find information about specific partnership programs and learn more about our partnerships with other organizations.
Definitions of geographic terms, why geographic areas are defined, and how the Census Bureau defines geographic areas.
We conduct research on geographic topics such as how to define geographic areas and how geography changes over time.
Visit our library of Census Bureau multimedia files. Collection formats include audio, video, mobile apps, images, and publications.
Official audio files from the Census Bureau, including "Profile America," a daily series of bite-sized statistics, placing current data in a historical context.
Infographics include information on the Census Bureau's history of data collection, our nation's veterans and the American Community Survey.
Read briefs and reports from Census Bureau experts.
Watch Census Bureau vignettes, testimonials, and video files.
Read research analyses from Census Bureau experts.
Access data through products and tools including data visualizations, mobile apps, interactive web apps and other software.
Developer portal to access services and documentation for the Census Bureau's APIs.
Explore Census Bureau data on your mobile device with interactive tools.
Find a multitude of DVDs, CDs and publications in print by topic.
These external sites provide more data.
Download extraction tools to help you get the in-depth data you need.
Learn more about our data from this collection of e-tutorials, presentations, webinars and other training materials. Sign up for training sessions.
Explore Census data with interactive visualizations covering a broad range of topics.
Learn how we serve the public as the most reliable source of data about the nation's people and economy.
Information about the U.S. Census Bureau.
Information about what we do at the U.S. Census Bureau.
Our researchers explore innovative ways to conduct surveys, increase respondent participation, reduce costs, and improve accuracy.
Our surveys provide periodic and comprehensive statistics about the nation, critical for government programs, policies, and decisionmaking.
Learn about other opportunities to collaborate with us.
Explore the rich historical background of an organization with roots almost as old as the nation.
Explore prospective positions available at the U.S. Census Bureau.
Information about the current field vacancies available at the U.S. Census Bureau Regional Offices.
Discover the latest in Census Bureau data releases, reports, and events.
The Census Bureau's Director writes on how we measure America's people, places and economy.
Find interesting and quirky statistics regarding national celebrations and major events.
Profile America is a daily, 60-second feature that uses interesting vignettes for that day to highlight information collected by the Census Bureau.
Find media toolkits, advisories, and all the latest Census news.
See what's coming up in releases and reports.
The most important change to the state and county models was the acceleration of the production schedule by one year to produce estimates for 2002 as well as 2001 in 2004. The model-based estimates of income and poverty for state and counties are now available with only a one-year lag, measured from the release of national estimates from the Annual Social and Economic Supplement (ASEC) of the Current Population Survey (CPS) for the relevant reference year.
We were able to make this change due to a successful effort to acquire input data on an earlier schedule. Specifically, we were able to acquire the food stamp data from the Food and Nutrition Service that are used in the county poverty models a year earlier than in previous years. As a result of obtaining the food stamp data on an earlier schedule, we also changed to using an earlier version of the state and county demographic population estimates. In previous years, we used the "second vintage" release of population estimates that included revisions from their first release. Although this wasn't necessary, we did so because the revised data were available and were generally thought to be more precise. Unpublished internal research on the impact of changing to the unrevised or "first vintage" estimates indicated minimal impact on the SAIPE program estimates from this change. Regardless of the impact on the estimates, we believe it is appropriate to use the first vintage population estimates since they are the official population estimates and are used for other purposes by the Census Bureau and others.
State Model Changes
Some changes were made to the CPS ASEC sampling weighting scheme that affected the direct CPS ASEC estimates for income year (IY) 2002. Though we did not apply the poverty and income models any differently because of these changes, we did modify our approach to estimating sampling error variances of the direct CPS ASEC estimates in two ways. First, in fitting sampling error models to direct estimated CPS ASEC sampling covariance matrices for 2001-2002, we estimated design effect parameters for 2002 that were distinct from those for 2000 - 2001 (within each age group). Previously design effects were assumed constant over time (but not age) when fitting the sampling error models. Out of concerns that the weighting changes in 2002 might affect the sampling variances, we allowed for distinct design effect in 2002. Second, the direct variance estimates for 2002 used in the sampling error modeling did not fully reflect the CPS ASEC weighting changes, as we did not have enough time to modify the variance estimation program to accomplish this. We were, however, able to obtain some variance estimates that did fully reflect the 2002 CPS ASEC weighting, though these variance estimates were approximate in other respects. Comparing these variances to others produced via the same methodology but without fully reflecting the weighting changes provided measures of the effects on variances of the weighting changes. These measures were used to multiplicatively adjust the 2002 poverty ratio variances obtained from the fitted sampling error models to reflect the estimated effects on variances of the weighting changes. The adjustments were constant over states within each age group. Such adjustments were not made to the sampling variances for the median income estimates because the approach used to obtain approximate variances (which used a linearization approach) was thought to be less appropriate for the median income estimates.
The effects of these variance adjustments were typically small. Design effects estimated for 2002 did not differ substantially from those estimated for 2000 - 2001. Also, the variance adjustments discussed had mostly small effects. They decreased the estimated sampling variances for age 18 - 64 poverty ratios by about 10 percent, but effects on the other age groups were only about a 3.5 percent reduction or less. In addition, sampling variances are updated as part of the iterative estimation scheme used for the poverty ratio models as described in the paper "Accounting for Uncertainty About Variance in Small Area Estimation," Bell (1999). This iterative updating almost certainly had more important effects in the sampling variances than the adjustments just discussed.
Due to the small number of years of sampling variances used in the sampling error modeling, and to the estimation of different design effects for 2002 versus 2000 - 2001, we decided not to attempt to estimate random state effects on the variances. The same decision was made for the production of the 2000 estimates last year, but this differed from what was done prior to 2000.
Sampling variances for IY 2001 CPS ASEC estimates were taken from sampling error modeling results for 2000 - 2001 produced last year, and were not affected by the issues just discussed. For further discussion of the sampling error models see "Sampling Error Modeling of Poverty and Income Statistics for States," (Otto and Bell, 1995).
County Model Changes
There were no methodology changes to the county models.