Guest blog post by Commerce Deputy Secretary Rebecca M. Blank 
Yesterday's U.S. Census Bureau report  shows that not only was the 2010 Census delivered on time and significantly under budget–but even more important, it was extremely accurate. I am proud of the extraordinary accomplishment by the Census Bureau and the Commerce Department in its success with the massive 2010 Decennial Census effort that gathered data vital to understanding our nation’s population and to allocating equal representation in our democratic system. The accuracy of the 2010 Decennial Census is particularly impressive considering outside predictions of failure. The Census was able to reverse a decades-long decline in survey response rates with its 2010 count.
The data released yesterday are from a post-enumeration survey of the 2010 Census called the Census Coverage Measurement (CCM) program, which measures the accuracy of the coverage of the nation’s household population (excluding the 8.0 million people in “group quarters,” such as nursing homes or college dorms). It surveys a sample of the 300.7 million people living in housing units and then matches the responses to the census, providing an estimate of exactly who was or wasn’t counted in the census. The results found that the 2010 Census had a very small net overcount–just 0.01 percent–which is statistically virtually the same as zero, and a significant improvement over the 0.49 percent overcount in 2000 and 1.61 percent undercount in 1990. You can learn more about how the Census Bureau conducts the CCM survey after the census to help measure its quality .
However, as in past surveys, this release shows that certain populations were undercounted. More work remains to address persistent causes of undercounting, such as poverty, mobility, language isolation, low levels of education, and general awareness of the survey, in addition to duplicate counts among the elderly and college students living away from home. As a nation, it is imperative that we work to address economic inequalities that impact those populations by promoting education, opportunities and jobs–particularly those in high-paying, high-quality science, technology, engineering and math fields.
The 2010 Census count shows how the U.S. population has grown and shifted over the last decade. People use this data to advocate for causes, rescue disaster victims, prevent diseases, research markets, locate pools of skilled workers and more. Not only does the Decennial Census determine the number of seats each state has in the U.S. House of Representatives, but more than $400 billion in federal funds are distributed every year to states and communities based in part on Census population data and American Community Survey (ACS) results. State and local governments use this data to plan new roads, new schools and new emergency services, and businesses use the data to develop new economic opportunities–all crucial for a safe, educated, equitable, and thriving democracy.
Yesterday's Census Coverage Measurement results underscore the accuracy of our federal statistics and provide useful information that will pave the way for the Department of Commerce and U.S. Census Bureau to achieve an even better and more inclusive 2020 Census.