As we’ve discussed in our Census blog series, the decennial Census is a count of the number of people in the United States that’s taken every 10 years. And that count impacts state representation and local and state budgets for various federal assistance programs.
In addition to counting the number of people during the decennial Census, the Census Bureau collects some basic demographic data from all respondents at the same time, and collects more detailed information from a sample of the population through the annual American Community Survey (ACS). These datasets can be used to answer questions about a geography, like a neighborhood, and can be helpful for nonprofit organizations, educational institutions, and community advocates.
In this blog, we’re going to take a look at the different information that can be found in the 2020 Census data, how it differs from what’s available via the ACS, and what community-driven questions this information can answer.
The 2020 Census
The initial results for the 2020 Census were released in April 2021, with some additional metrics for analysis and insights released in May. These releases have included the apportionment population and number of representatives per state; the total resident population for each of the 50 states, Washington D.C., and Puerto Rico; and the overseas population for each of the 50 states and Washington D.C.
Most recently, redistricting data was initially released on August 12, 2021. The raw data allows states to begin determining new boundaries for voting districts. The final redistricting data will be made available to the public by the end of September 2021 with tools to help access the data more easily.
This data available from the Census includes information for all 50 states, Washington D.C., and Puerto Rico, and for more granular geographies including counties, townships, cities, voting districts, school districts, tracts, and census blocks. This data will include the following information that in decades past proved essential for organizations and advocates to make key decisions:
- Population totals
- Population totals by race and by Hispanic/Latino origin
- Voting-age population (18 and older) totals by race and Hispanic/Latino origin
- Population totals in group quarters by type (e.g.: nursing homes, prisons, military barracks, college dormitories)
- Housing unit counts
- Occupancy status (occupied or vacant) for housing units
- Additional demographic statistics for age groups, sex, and race and ethnicity
The American Community Survey
By contrast, the American Community Survey (ACS) is an annual survey of a sample of the population that is meant to measure the changing social and economic characteristics of the U.S. population, including education, housing, employment, and more. It uses data from a relatively small number of people to represent the larger population. Because this is data taken from a sample of the population, it’s important to keep in mind that there are margins of error that don’t apply to the whole-population number of the Census.
Because ACS data is collected annually and from a smaller selection of people, there is more data on more topics that can be collected compared to the decennial Census. The ACS can provide a more detailed look at aspects of this sample—and by extension, the population it represents—including education, employment, internet access, transportation, and more.
| Full List of ACS Subjects | |
Population
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Housing
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*Data points that overlap with Census data
Questions the 2020 Census Can Answer
The complete Census data alone can answer several questions that decision makers may have, while ACS data points might provide additional details later in the decision-making process. Here are some examples of questions, and the data that will be available to answer them:
How many people live in ___ (county/city/block)?
This is one of the most basic questions that the Census data can answer, as the main purpose of the decennial Census is to collect a population count for the entire United States and the smaller geographies that make it up.
How many people living in ___ are of voting age?
In addition to total population counts, the Census data provides the total number of people aged 18 and older (legal voting age).
What is the racial/ethnic breakdown of a geographic area?
Census datasets include population by race and ethnicity, which allows decision makers to get an idea of the racial and/or ethnic makeup of a given geography. This data also allows for more specific questions, such as How many Black people live in Detroit? Or How many Detroiters identify as Hispanic?
How has the racial and ethnic makeup of my city changed since 2010?
The data on population by race and ethnicity can also answer the question of how the racial and/or ethnic makeup of a geography has changed over time. Answering this question simply requires comparing the 2020 Census data to the 2010 Census data.
How many housing units are in a geographic area?
The 2020 Census data includes the number of housing units in addition to the number of people living in an area.
How many housing units in this area are vacant? Occupied?
The 2020 Census data also includes the occupancy status of housing units, making it easy to answer questions about where people are living, or where there is a surplus of vacant units.
What percentage of the population lives in a correctional facility?
The Census population totals include the total number of people who are living in various types of group quarters, including nursing homes, correctional facilities, military barracks, and college dormitories. This data can be compared to the total population count to determine the percentage of the population who are living in a specific type of group quarters.