Delays to 2020 Census input data availability resulting from COVID-19 pandemic have introduced challenges for the production of our Vintage 2021 estimates--especially in terms of developing the April 1, 2020 base to build our estimates from. As a result, the Census Bureau's Population Estimates Program has developed a "blended base" which is 2010 Census-based and controlled to elements from the 2020 Census (and other sources) for the Vintage 2021 estimates. We invite you to learn more about the methodology of our "blended base" and other anticipated changes for Vintage 2021 and beyond.