In addition to the full-count decennial census, which counts every resident of the country and where they live on April 1, every ten years ending in zero, the U.S. Census Bureau releases annual population estimates, known as the “vintage” for that year. Each vintage employs a distinct methodology for population estimation. Some years yield highly accurate results. Others are less precise.
Vintage 2023: A Not-So-Very-Good Year?
In hindsight, one of the vintages with less precision was the vintage 2023. It significantly underestimated the population at both the national and state levels. Did you know that there were 1.89 million more individuals nationally and 225,000 more in Texas than was indicated by vintage 2023?
These inaccuracies stemmed from the survey’s limitations in estimating the international migration component. The net international migration numbers were off by 1.15 million in 2023 and 690,000 in 2022 at the national level. The survey-based method of estimation lagged and was inadequate for several reasons, particularly because it failed to account for the rapid and significant increase in migration that was occurring.
Tweaking the Methodology
The Census Bureau fine-tunes its methodology from year to year. The most recent vintage (2024) has a revised methodology that integrates administrative data with survey data to estimate the national and state population. Each new data vintage updates the most recent year’s population estimates while also revising past estimates up to the base year. The Census Bureau advises against mixing vintages in a single analysis, emphasizing that the most recent vintage supersedes all preceding ones. Therefore, the comparison above is intended for illustrative purposes only.
The trickiest part of the population estimation is the migration component, which the Census Bureau estimates by relying primarily on the American Community Survey (ACS). The post-pandemic period—especially 2022 and 2023—were not typical years, and the surge of asylum seekers at the border could not be captured by the existing framework. For vintage 2024, the Census Bureau has added administrative data sources on immigration that are better able to capture the short sudden spikes in immigration. As net international migration has become the primary driver of the nation’s population growth, this integration has become essential, and the increased numbers reflect this change. With the vintage 2024 and the revised estimates, the population estimates are higher at the state and national level and more on par with other federal agency projections. In 2024, the U.S. population grew by 1 percent, and Texas’ population growth was 1.8 percent.
Revisions and More Refinements
Revisions are an essential aspect of all economic data. Agencies that release economic data often face the challenge of balancing timeliness with accuracy, and revisions help refine and improve the data as more information becomes available. Each data release, or “vintage,” from the Census Bureau includes an explanation of any methodology changes and provides a schedule for when updated data will be available, ensuring transparency. This approach fosters trust and appreciation for the data’s reliability and continuous improvement.
