According to the PES (Post-Enumeration Survey), which states had undercounts?
- Arkansas (-5.04),
- Florida (-3.48),
- Illinois (-1.97),
- Mississippi (-4.11),
- Tennessee (-4.78), and
- Texas (-1.92).
And overcounts?
- Delaware (+5.45),
- Hawaii (+6.79),
- Massachusetts (+2.24),
- Minnesota (+3.84),
- New York (+3.44),
- Ohio (+1.49),
- Rhode Island (+5.05), and
- Utah (+2.59)
Why was there an undercount or overcount in my state?
While the 2020 Post-Enumeration Survey can estimate undercounts and overcounts in the census, PES data cannot answer why a particular state may have experienced one.
Based on the PES results, can states change their 2020 Census counts?
The quick answer is “No.”
Post-Enumeration Survey estimates are created to help data users better understand the quality of the census counts. The estimates demonstrate the Census Bureau’s commitment to transparency and are a key tool for the Census Bureau to build and apply lessons from the 2020 Census while planning for the 2030 Census.
The Census Bureau offers the 2020 Census Count Question Resolution (CQR) operation to give states (and tribal and local governments) the opportunity to request a review of their boundaries and housing counts to identify errors that may have occurred while processing their 2020 Census counts.
CQR does not alter redistricting data, apportionment results or other 2020 Census data products. If changes are made, corrected 2020 Census counts will be issued to governmental units, and these corrected counts will also be included in the population estimates base.
The Census Bureau is also proposing a new program called the 2020 Post-Census Group Quarters Review that, upon approval, will allow governmental units the opportunity to request the Census Bureau to review their population counts for group quarter facilities. The PES results are not factored into either of these reviews.
The Census Bureau has begun researching the feasibility of taking coverage measures from 2020 Demographic Analysis and the 2020 Post-Enumeration Survey to help inform the development of the annual population estimates.
Why do some states’ undercounts and overcounts have such high standard errors?
Standard errors quantify the amount of uncertainty in the estimates because they are based on a sample of people rather than a census of everyone. The amount of sample in each state depends on the number of people in the state and other more technical considerations.
The PES results are derived from 161,000 housing units in a random sample of 10,000 blocks across the United States and Washington, D.C. States with smaller sample sizes generally have larger standard errors.
The standard errors are also impacted by the number of completed interviews, so they vary among the states because they had different numbers of respondents.
How did these state-level undercounts and overcounts compare with those in the 2010 Census?
See Appendix Table 3 on page 16 in the National Census Coverage Estimates for People in the United States by Demographic Characteristics Report for a list of the PES results from 2010 and 2020.
The PES confirms that while there were overcounts and undercounts in the 2020 Census, they were not outside the range of variability we have come to expect from prior decades.
The 2010 PES estimated that no states had statistically significant undercounts or overcounts in the 2010 Census. In the 2000 Census, the PES estimated 22 states and the District of Columbia had statistically significant undercounts or overcounts.
However, it’s important to note that we have improved the methods we use to estimate 2020 state-level net coverage errors and their sampling error. These improvements were designed to reduce the bias of the state coverage estimates and more accurately measure the sampling error of the estimates.
That means any such comparison of estimates is subject to different sources of error and uncertainty. As a consequence, the statistical uncertainty associated with 2020-to-2010 state level comparisons will be greater than that indicated by the published standard errors, but how much greater is unknown.
So, while informative, the 2020-to-2010 state level comparisons cannot be considered definitive.
We discuss the methodology in more detail in the Source and Accuracy Statement.
Do you know what groups were undercounted or overcounted in each state? And where coverage error happened in a state?
No, because sample sizes within most states do not support such estimates. That is why today’s results are not broken down by demographic characteristics or geographic areas within the states. The Census Bureau did not release state estimates of coverage by demographic groups following the 2010 PES, either.
Given the sample size for the 2020 PES and the assumptions required to make substate geographic estimates, we cannot include county or place estimates in the 2020 PES reports.
The Post-Enumeration Survey: Measuring Coverage Error provides more information on why county and place estimates are not included in the PES reports.
https://www.census.gov/library/stories/2022/05/2020-census-undercount-overcount-rates-by-state.html
