From Neighborhoods to the Entire Nation: How the ACS Shapes Funding, Planning, and Policy 

By Druta Bhatt

The ACS and Why It Matters  

The U.S. Census Bureau released the latest American Community Survey (ACS) 2024 1-year estimates on September 11. ACS is an ongoing survey that collects demographic, social, economic and housing characteristics of the U.S. population. Since its first publication in 2010, the ACS has become a cornerstone of public data, with new results released annually (except in 2020, when the pandemic disrupted collection).  

Unlike the traditional decennial census, which surveys practically every U.S. household once a decade, the ACS uses rolling interviews with a smaller sample size of about 3 million households each year — roughly 1 in 100. This complex sample-survey design provides timely snapshots of everything from national trends to more localized, individual census tract data. 

Why Census Data Fuels Decision-Making 

In a world where data is the new oil, the ACS is one of the most trusted and accessible sources of information.  In 2021, used alongside the decennial census, it helped direct more than $2.8 trillion in federal funding to states and communities — shaping investments in housing, — shaping, education, transportation and more. 


A Brief History: From Horsemen to Digital Surveys 

The first census in 1790 was conducted by horseback riders who collected just six data points from every household across 13 early states. Today’s census tools exist not only because of government innovation, but also the advocacy of nonprofits, community leaders, local organizations and small businesses.  Fun fact: the “census tract” — the backbone of local data today — was created because a New York City minister wanted a better way to understand how immigration patterns would affect his congregation. Since then, a completely new geographic system was created for data collection, outside of traditional political boundaries like election districts, city, states, and so on. Local governments and nonprofits pushed the Census Bureau to adopt the system nationwide. 

The Birth of the ACS 

By the mid-20th century, with the expansion of U.S. territory, the decennial census had grown too costly and complex. However, it was the only source of localized data for most small U.S. cities — and the need for more frequent, detailed data was growing. As a result, stakeholders lobbied Congress to continue funding the census and, soon after, a prototype of the ACS was created as a cost-effective solution. Instead of waiting 10 years, communities can now access rolling annual updates to track changes in real time.  

Types of ACS Data Products 

ACS data has four kinds of data products, the first three of which follow the same data format, but there is a trade-off between accuracy and timeliness. Here’s an overview: 

  • 1-year estimates, like the current 2024 ACS data release, offer the most current picture, based on a smaller sample. Useful for large geographies, but with slightly higher margins of error. 

  • 1-year supplemental estimates are released soon after the 1-year estimates and are designed to focus on areas with fewer than 20,000 residents that aren’t included in the initial survey. 

  • Released later, 5-year estimates have a larger sample and are more reliable. They’re best for studying long-term trends and analyzing smaller areas like census tracts or rural communities. The latest data from 2024 is slated for publication in December of this year. 

  • Different from the other products, Public Use Microdata Sample (PUMS) Files have anonymized, household-level interview responses that allow researchers to create their own analyses and statistical estimates.  

Each year, the Census Bureau shares a release schedule for each of the ACS data products. You can access the 2024 data schedule here.  

How ACS Data is Used 

 Today, ACS data covers broad topics like housing, education, health, economy, race and ethnicity and family dynamics.  This data is used to:  

  • Plan services and funding, like determining the dollar amount of subsidies and the eligible population size/area, for example low- and moderate-income census tracts and the number of households in those tracts.  

  • Track demographic shifts and predict changes in areas like school enrollment, housing demand and workforce trends and, ideally, redistribute resources accordingly.  

  • Support advocacy and policy by providing evidence of community needs like housing quality or healthcare access.  

You don’t need to be a data expert to use census data. While it may feel overwhelming at first, the tools are designed to feel approachable. And, with a little practice, they become a valuable resource for organizations, researchers, community advocates and residents alike. The latest Census Bureau data site is especially user-friendly: you can simply select topics, geographies and time periods to quickly preview the tables that matter most to you. 

Other census resources: 

  • A guide to all Census Bureau products  

  • Census quick facts: commonly used data points for state, county or city