Overview of the four sources of population data
Accurate and reliable population data is essential as we strive to understand our communities and plan for the future. From determining congressional districts to allocating resources for schools and healthcare, population data drives decision-making at all levels of government and beyond.
In this blog post, we'll take a closer look at four commonly used sources of population data: the Decennial Census, American Community Survey (ACS), Population Estimate Program (PEP), and Connecticut Department of Public Health (CT DPH) Population Estimates. Continue reading to learn more about these sources.
The Decennial Census is conducted by the U.S. Census Bureau every ten years, the most recent being in 2020. It aims to count every person residing in the United States, collecting demographic information such as age, sex, race/ethnicity, and homeowner/renter status. The Decennial Census provides congressional apportionment, policymaking, resource allocation, and planning data at national, state, and local levels. It also plays a significant historical role in understanding population trends and changes.
The ACS is an ongoing survey conducted by the U.S. Census Bureau that provides more frequent and timely population data than the Decennial Census. It uses a sample-based approach, reaching millions of households yearly. Because it is a sample and not a count, the numbers are referred to as estimates. This survey collects detailed information on socioeconomic and housing characteristics. The ACS is a valuable data source for understanding community-level demographics, economic trends, educational attainment, housing characteristics, and more.
The Population Estimate Program (PEP) by the U.S. Census Bureau produces annual population estimates for states, counties, and other geographic areas. It uses a combination of administrative records, such as birth and death records, and survey data to estimate population changes between Decennial Censuses. Government agencies, businesses, and researchers widely use it for policy planning, resource allocation, and projections.
The CT DPH generates population estimates at the town level. These are the official estimates per Connecticut statutes. The CT DPH uses a methodology that combines various data sources, such as birth and death records, school enrollments, Medicare enrollment, and DMV data, to estimate each Connecticut town’s population.
We will be going deeper into the differences, strengths, and weaknesses of these different products in this series. Sign up for our newsletter to hear about the next blog post, or sign up for an upcoming webinar on population estimates.
Scenario
The Council of Government (COG) in the New England region gathered for their annual meeting on regional planning. The COG comprised representatives from various towns and cities within the region, responsible for coordinating regional development and policy initiatives.
The agenda for the meeting included discussions on population data, as it is crucial for the COG to make informed decisions about resource allocation, infrastructure planning, and emergency preparedness. Four sources of population data were presented for consideration: the Decennial Census, the American Community Survey (ACS), the Population Estimate Program (PEP), and the Connecticut Department of Public Health (CT DPH) population by town estimate.
The COG members engaged in a robust discussion on the pros and cons of each data source. They recognized the Decennial Census as the most comprehensive data source, providing a detailed population count every ten years. However, they also acknowledged that it could be outdated when it's released and might not capture population changes accurately.
The ACS was recognized for its timeliness and ability to provide data on various socio-economic characteristics. The COG members noted that the ACS could offer valuable insights into the region's population dynamics, such as income levels, educational attainment, and commuting patterns. However, it was noted that smaller geographies have more uncertainty in the data.
The PEP was recognized for its annual population estimates, which could provide more up-to-date data compared to the Decennial Census. The COG members acknowledged that the PEP could help identify population trends and project the region’s future growth.
The CT DPH population by town estimate was recognized for its localized data and relevance to public health planning. The COG members noted that it could provide insights into healthcare facilities and services distribution, which could impact emergency preparedness and response efforts.
After careful deliberation, the COG members decided to utilize a combination of all four data sources to provide insights into their decision-making. They recognized the strengths and limitations of each source and acknowledged the importance of triangulating multiple data sets to obtain a comprehensive and accurate understanding of the region's population dynamics.
The COG members concluded the meeting by expressing their commitment to data-driven decision-making and using the four population data sources to effectively guide their regional planning efforts. They were confident that this approach would enable them to make informed decisions that would benefit the communities they served and promote sustainable and equitable development in the New England region.