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RESEARCH BRIEF  |  Children  |  August 2023

The 2020 Census Undercount of Children in Texas Counties

In partnership with Dr. Bill O’Hare from Count All Kids, this research brief estimates the undercount of Texas children by county in the 2020 Census.

By: Dr. Francisco A. Castellanos-SosaA, Texas Census Institute, Senior Research Associate
Dr. William P. O’Hare, Count All Kids Campaign, Consultant


The Children’s Census Initiative

The Texas Census Institute created the Children’s Census Initiative to improve the accuracy with which the 2030 Census will count Texas children. The initiative comprises five related parts, each tackling a specific aspect of this phenomenon to enable a thorough analysis and informed decision-making. This research brief is the first product of the initiative, and its objective is to serve as a descriptive overview of child undercounts in the state by providing an innovative measurement of children’s undercount in Texas counties and regions. The following four topics are part of this initiative and will study 1) the counties with high net child undercount in Texas, 2) the determinants of Texas child undercount, 3) its economic impact, and 4) its short-and long-term implications. Collectively, this initiative will offer valuable insights and recommendations for addressing the U.S. Census child undercount and empowering stakeholders with the knowledge for effective decision-making and action.

Research Overview

There was a substantial undercount of children in the 2020 U.S. Census and particularly in Texas. Based on the U.S. Census Bureau’s Demographic Analysis, the net undercount of children in the U.S. Census increased from 1.7% in 2010 to 2.1% in 2020. The net undercount of children contrasts with a 0.2% overcount for adults. While these national numbers are informative, state and local data from the decennial census is critical to gain a constructive understanding of the issue. However, little is known about undercounting children at the county level. To inform this issue, we estimated the Texas net child undercount at the county level and studied its spatial distribution using data from the 2020 Census and the Vintage 2020 population estimates. This study builds on the work of Dr. William P. O’Hare, who finds Texas had more counties with high net undercounts of children than any other state (either in number or rate terms).

Main Findings

The 2020 Census undercounted an estimated 153,633 children in Texas.
190 out of 254 Texas counties (74.8%) experienced a net child undercount.
Dallas County, in the Metroplex region, experienced the largest county undercount (35,245 children). 
71.8% of child undercount in Texas occurs in three of its twelve regions: South Texas, Gulf Coast, and Metroplex.

Figure 1 Net child undercount in Texas counties

Note: Color bins identify each region. A darker red color indicates higher undercounting. A darker blue color indicates higher overcounting. Negative and positive values indicate undercounting and overcounting, respectively.

Author’s Message

The net undercount of children (age 0 to 17) in the U.S. Census is high and has been growing in recent decades. This study provides a detailed analysis of child undercounts at the county and regional level in Texas and explores its regional patterns. These results can serve as a roadmap for deeper analysis. 

Census-related data is used to determine the distribution of funding for 350+ federal programs, totaling more than $2.8 trillion each year. Counties with an undercount will not receive the full federal funding they are entitled to, impacting budgets for things like schools, health centers, and childcare centers.  Furthermore, counties with an undercount will not have accurate data for future planning.

To address the impact of an undercount, leaders may want to explore ways to compensate counties that experience a high undercount of children. Similarly, leaders in counties with a high undercount of children may want to work with the Census Bureau to look for additional ways to correct the undercount of children in future censuses. The results shown here can be used to start building a targeted approach to increasing the count accuracy of children in the 2030 Census. 

Acknowledgements: The authors appreciate the insightful support provided by Helen You, Deborah Stein, and Monica Cruz.


1) Why does the U.S. Census Bureau not publish undercounting and overcounting estimates at the county level for children?

As it is well known, the U.S. Census Bureau assesses the quality (undercounting or overcounting) of its Decennial Census using the Post-Enumeration Survey (PES) and the Demographic Analysis (DA). 

The PES was implemented in 2020 by characteristics of the housing units only to the national and state levels. The PES uses the location of the housing units to obtain results at the subnational level, but it does not consider demographic characteristics such as age or gender. Moreover, “…the sample size for the 2020 PES and the assumptions required to make unbiased sub-state estimates, the Census Bureau was unable to include county or place estimates in the 2020 PES reports, as well.” (U.S. Census Bureau, 2022). 

On the other hand, the Demographic Analysis uses “…current and historical vital records, data on international migration, and Medicare records to produce national estimates of the population on April 1 by age, sex, the DA race categories, and Hispanic origin.” (U.S. Census Bureau, 2022). While the DA is rich in demographic characteristics, it cannot identify the current place of residence of the population since a great part of it is based on vital records. Therefore, due to its nature, the official undercounting or overcounting by demographic characteristics is estimated at the national level only.

Therefore, it is not possible to obtain an official undercounting and overcounting estimate at the county level for children.

2) Why are we using counties as geographies?

This approach implies that undercounting estimation is built upon variables that are considered determinants of undercounting, according to the theory.

3) How accurate or precise are our net child undercount estimates?

While there is no statistical measure of accuracy or precision for our estimates, they were built using official publicly available data from the U.S. Census Bureau.