U.S. Census Data for Research

The Census survey that most of us are familiar with is the Decennial Census of Population and Housing. The decennial census is constitutionally mandated to occur every 10 years. The main function of the census is congressional reapportionment, or to distribute Congressional representatives fairly to areas of the country based on population. The aim of the decennial census is to count everyone. The 2020 Decennial Census was the most recent decennial census. 

You can quickly access decennial census data using Social Explorer:

• Navigate to Social Explorer (UVA affiliates only)
• Select “Explore Maps” to explore datasets using an interactive mapping web tool
  • Select the “United States” map for Census Tables
  • Use the Search Bar or Zoom to narrow down specific geographies of interest
  • Select “Change Data” to pick a dataset by Year and Topic
  • After selecting a topic, select an available Census Table of interest
  • Options for saving or exporting your map include saving your project, exporting the map as an image, and creating a downloadable tabular report from selected geographies on the map 
• Select “Tables” to create a report from a specific survey 
  • Select and add your geographies of interest from the drop-down menus
  • Select and add your tables of interest from the drop menu
  • View the report online or select a method of download
• Select “Data Dictionary and Documentation” for more information on specific variables

See the Social Explorer Guides and Videos for more information. The Social Explorer LibGuide is also a great resource for getting started, as well as diving deeper into specific topics. 

Redistricting is the process of redrawing electoral boundaries within the states to reflect new trends in population. The decennial census data is critical to the process of redistricting. For more information on redistricting and the Census products related to redistricting, visit the Redistricting page from the Census. 

Many summary tables are available to download on the 2020 Decennial Census Data Products page. Browse these resources to see if there is an off-the-shelf data table that suits your research needs.

If you can’t find a table that suits your purposes, navigate to data.census.gov to explore the available data tables. To filter to only see the 2020 Decennial Census and its related data products: 

• Navigate to data.census.gov and Select “Advanced Filter”
• Select “Surveys”
• Select “Decennial Census”
• Select a specific survey you're looking for (e.g. “Demographic Profile”) or select multiple to explore
• Filter to the 2020 Census by Selecting “Years” and Selecting “2020"

Because the 2020 Decennial Census administration was interrupted due to the COVID-19 Pandemic, there may be additional considerations to using this data. See the section on the COVID-19 Pandemic under the Data Ethics section of this guide for more information.

The American Community Survey (ACS) is administered every year by the Census Bureau. It is designed to be more detailed than the decennial census and more frequent to understand more up-to-date changes in communities. As such, not everyone responds to the American Community Survey, only a sample of households receive the survey. Yet the data is still high quality and trusted by decision-makers at all levels of federal, state, and local government, as well as businesses, nonprofits, and academic researchers. To understand more about the differences between the American Community Survey and the decennial census, see this comparison of the two surveys available on the Census Bureau website. This Census Bureau workshop gives an overview of the Census Bureau data products, available geographies, and decennial census versus American Community Survey use. For more information on 1-year, 3-year, or 5-year estimates visit the Census Glossary.

You can quickly access ACS data using Social Explorer:

• Navigate to Social Explorer (UVA affiliates only)
• Select “Explore Maps” to explore datasets using an interactive mapping web tool
  • Select the “United States” map for Census Tables
  • Use the Search Bar or Zoom to narrow down specific geographies of interest
  • Select “Change Data” to pick a dataset by Year and Topic
  • After selecting a topic, select an available ACS Table of interest
  • Options for saving or exporting your map include saving your project, exporting the map as an image, and creating a downloadable tabular report from selected geographies on the map 
• Select “Tables” to create a report from a specific survey 
  • Select and add your geographies of interest from the drop-down menus
  • Select and add your tables of interest from the drop menu
  • View the report online or select a method of download
• Select “Data Dictionary and Documentation” for more information on specific variables

See the Social Explorer Guides and Videos for more information. The Social Explorer LibGuide is also a great resource for getting started, as well as diving deeper into specific topics.

To access aggregate ACS data from data.census.gov:

• Navigate to data.census.gov and select “Advanced Filter”
• Within the Filter Window, select “Surveys” and Select “American Community Survey”
• Select the type of estimates you want (i.e. 1-year, 3-year, or 5-year)
• Browse Subject Tables or
• Search by topic (e.g. “Poverty” or "Education") 

American Community Survey data is also available as microdata (i.e. household-level information). To access the American Community Survey microdata, visit IPUMS USA. Browsing the available variables and downloading the data required a free account. Once you have an account, you can select variables from the catalog and add them to your cart to create an extract. If you access the American Community Survey microdata through IPUMS, make sure you follow the terms of use (which specify that the data, though publicly accessible, may not be redistributed) and citation guide.

When choosing between using the decennial census and ACS for research, the biggest consideration will likely be topic. The goal of the decennial census is to enumerate the population, so it provides the most accurate population estimates. The goal of the ACS is to provide a social and economic snapshot of the population. The ACS spans a wider variety of topics, drawing from a sample of households. Another consideration will be timing. If your geography of interest has undergone large population changes in between decennial censuses, the ACS may more accurately capture up-to-date trends. There are a few other differences between the decennial census and ACS, which are explained more in the Census publication, "What All Data Users Need to Know."

The American Community Survey produces several different types of data tables and profiles. Each table and profile has a specific topical,  geographic, or temporal scope. To understand more about the differences in the types of data products available from the ACS, visit the Census Bureau webpage on the American Community Survey Data Tables. Some of the commonly used tables and profiles include:

• Data Profiles (DP), which include the most commonly requested demographic information, as well as social, housing, and economic characteristics. DP Tables are the entryway to the American Community Survey and easy to use and understand for most users.
• Detailed Tables (B or C) contain granular information for all subjects and geographies.
• Subject Tables (S) provide American Community Survey data for a topic, often by demographic cross-sections. 

Users of the American Community Survey will need to consider which type of estimates to use. The best estimates for your research will depend on your research needs and data availability. Choosing an American Community Survey estimate type requires balancing the considerations of data timeliness with accuracy. Visit the Census Bureau guidelines on choosing estimate type for more information. The types of American Community Survey estimates are:

• 1-year estimates, which provide the most current data for areas with populations of 65,000 or more
• 5-year estimates, which provide the most precise data for geographic area with small populations by pooling several years of data

Users searching for data for geographic areas with small populations will find that 5-year estimates are their only option. For areas with a population of at least 65,000 or more, 1-year estimates will provide more current data with larger margins of error. If your area of research involves a phenomena that is rapidly changing, 1-year estimates may capture that change better than 5-year. For more information on estimates and guidance on their use, see the Census publication, "What All Data Users Need to Know".

Use the Census Survey Explorer to understand all the surveys administered by the Census. Depending on your need, there is likely a Census Survey with data you can use for your research. Use the Census Survey Explorer to understand surveys by frequency, geography, topics, and subtopic. 

The Current Population Survey (CPS) is a monthly survey administered by the Census Bureau and sponsored by the Bureau of Labor Statistics. The Current Population Survey provides up-to-date, frequent data on labor force statistics, as well as other occasional supplemental topics. Aggregate estimates from the Current Population Survey can be accessed on the Census Bureau website. The Current Population Survey Microdata (i.e. household-level information) can be accessed via IPUMS CPS. Browsing the available variables and downloading the data requires a free account. Once you have an account, you can select variables from the catalog and add them to your cart to create an extract. If you access the Current Population Survey microdata through IPUMS, make sure you follow the terms of use (which specify that the data, though publicly accessible, may not be redistributed) and citation guide.

The Longitudinal Employer-Household Dynamics (LEHD) program is a group of Census Bureau surveys focusing on economic relationships between employers and employees. LEHD surveys include:

• LEHD Origin-Destination Employment Statistics (LODES), which provides detailed information on commuting flows by industry and demographics at detailed geographic granularity. LODES data is easily accessed, visualized, and downloaded using the OnTheMap Tool.
• Job-to-Job Flows (J2J), which provides data on job transitions, including hires and separations, by industry and demographics. J2J is easily visualized and accessed using the Job-to-Job Flows Explorer and extracted using the LED Extraction Tool.
• Quarterly Workforce Indicators (QWI) provide comprehensive economic indicators by firm characteristics and worker demographics. QWI can be visualized using the QWI Explorer and extracted using the LED Extraction Tool.

The Household Pulse Survey is a newer Census Bureau survey and data product born during the COVID-19 Pandemic. The survey is designed to quickly measure information on emerging topics. The data can be visualized and accessed on the Household Pulse Survey Interactive Tool.

The Census Bureau produces a variety of experimental data products on emerging topics, including environmental hazards and resilience. The Census Bureau also specifies a select set of surveys and data products that are designed to address equity, known as Data Equity Tools. 

For more information on alternative ways to access the Census, contact data@virginia.edu