In short, yes. While both sets of estimates interpolate annual population figures between decennial censuses, the Boyd Center’s version is periodically revised to align with new population estimate vintages that adapt to estimate base adjustments of both population and characteristics. The Census Bureau’s intercensal products remain fixed to the April 1, 2020, Census results and no other updates are made. Moreover, the Boyd Center’s estimates are designed to be connected to the population level on July 1, 2020, as reflected in the latest Census Bureau population estimate vintage.

Our Intercensal Estimates are based on the U.S. Census Bureau’s Vintage 2020 Population Estimates covering the period from 2010 to 2020. However we take the July 1, 2020 population from the vintage year population estimates.

These intercensal estimates were developed to support the Boyd Center’s population projections. Updated intercensal estimates are released in conjunction with that product’s biannual update cycle.

The Boyd Center Intercensal Estimates cover the period from July 1, 2010, to July 1, 2020. The value for July 1, 2010 is based on U.S. Census Bureau estimates published in the Vintage 2020 evaluation estimates. The value for July 1, 2020 is connected to a different dataset. Our Vintage 2022 estimates are connected to the Vintage 2022 County Population by Characteristics published in June 2023. Our Vintage 2024 release is connected to the 2024 version of the same file.

This decade the Bureau adopted a new methodology which incorporates additional data and methodological improvements that address delays in obtaining detailed 2020 Census data and related quality concerns. This new “Blended Base” approach means that the July 1, 2020, population published in this decade’s postcensal population estimate vintages changes with each vintage release in terms of both population and characteristic makeup. The Census Bureau’s intercensal estimates remained fixed to the April 1, 2020 Census results even the estimates change.

Like the source population estimate data, characteristics are available for three areas:  age, race/Hispanic Ethnicity, and sex. With regard to the race groups, an important modification that is made to support our population projections. Specifically, the “non-Hispanic other races” category combines four race groups published in the Census Bureau estimates: American Indian and Alaska Native alone, Asian alone, Native Hawaiian and Other Pacific Islander alone, and two or more races.

The July 1, 2020, population from related vintage population estimates serves as the endpoint for the Boyd Center Intercensal Estimates. The endpoint is changed to a later population estimate vintage to support production of population projections. The Census Bureau’s intercensal product uses April 1, 2020 from the decennial census.

Once intercensal estimates are available, they become the preferred population series for the decade. For example, after its publication in 2025, the U.S. Census Bureau’s intercensal series will become the Census Bureau’s official annual estimate of population for July 1 from 2010 to 2020 and will supersede all other vintages published last decade. The Census Bureau provides guidance for data users that includes additional information on this topic.

Multidecade population series: The estimates should connect to the U.S. Census Bureau’s 2000-2010 population projections as well as the most current vintage population estimates for the 2020s.

Denominators: Per capita calculations and other rates of incidence tied to state or county characteristics including age, race, Hispanic ethnicity and sex

The difference between the decennial census and the estimate is called the error of closure. Differences attributed to the estimate. When the 2020 estimate endpoint is moved to correct for this error, the interceding values for 2011 to 2019 must also adjusted. In most cases, the error of closure is spread evenly or distributed linearly across the entire decade.

These annual estimates were interpolated using a formula developed by Census Bureau mathematician Prithwis Das Gupta. For 2000-2010, the Bureau employed Das Gupta’s Method 6 to correct the error of closure. For 2020, the agency is expected to switch to Das Gupta Method 2. In this approach, the correction applied to each figure is directly proportional to the time elapsed since July 1, 2010, and the correction increases arithmetically over time.
More details about both formulas, and exceptions where linear interpolation cannot be used, are found in our technical documentation.

Tennessee data for 2020 and later is available for download from the U.S. Census Bureau website. Make sure to use intercensal and postcensal estimate data from similar vintages.