Local governments may challenge these population estimates through a  process established by the Bureau’s Population Estimates Challenge  Program. In practice, according to agency  officials, the Bureau generally accepted all challenges, largely without  regard to the data sources provided so long as they supported  calculations of population change and covered the reporting periods  required by the challenge program. According to Bureau officials,  these changes are based on research that shows that estimates based  on some methods and records (e.g., births, deaths, and migration) are  substantially more accurate than estimates based on others. The Bureau  modified procedures so that challenges by subcounty governments to the  Bureau’s estimates of people living in traditional housing—not living in  group quarters arrangements—will no longer affect county-level  population estimates. According to the change, any  challenge that results in an increase to the estimate of a subcounty  community’s population living in traditional housing will be offset by a  downward revision to the estimate for all other communities in the same  county, in effect reallocating the estimated population within the county. The Bureau also changed procedures so that it routinely reviews  subcounty population challenges in light of each community’s population  growth trend, requiring corroborating information when a government  claims population growth that is inconsistent with the trend. The Bureau Reviews Quality of Calculations and Requires Local Governments to Certify that Data Are Accurate

Challenge program officials told us that the program focuses its quality  assurance on (1) reviewing the calculations presented in the  documentation submitted by local governments as part of challenge  submissions and (2) checking documents and calculations for internal  consistency. Moving forward, according to officials, the Bureau is preparing a quality  assurance plan for Bureau staff who review challenges to better ensure  proper handling and processing of challenges, as well as the review of  calculations. The Bureau has Limited Plans for Using Local Records to Supplement National Records for 2020

The Bureau is exploring the use of local records for the 2020 Census, but  this effort will be of a lower priority than research on the use of national  administrative records, in part because national records show greater  promise than local records for controlling costs. In contrast, Bureau officials believe that the use of local administrative  records is most likely to support the development of the 2020 address list. However, the process of going door-to-door is labor  intensive. The Bureau  would like to update this information continuously rather than wait to  receive the input as part of a one-time decennial update. The officials stated that while it is important to  continue research on local records, because they may be helpful in  targeting decennial operations to hard-to-count groups or those in certain  geographic areas, the results of 2010 Census research and testing on  national records has led Bureau officials to conclude that continuing  research on national records, such as those listed in figure 2, should be a  higher priority. Agency Comments and Our Evaluation

We provided a draft of this report to the Department of Commerce. Appendix I: Objectives, Scope, and Methodology

To describe the U.S. Census Bureau’s (Bureau) changes to how local  administrative records will be used in the challenge program, we reviewed  the August 10, 2012, Federal Register outlining proposed changes; the  final rule, which was issued in the January 3, 2013, Federal Register;  Bureau reports and presentations, which served as the basis for the  changes; and comments received from state and local data experts  solicited by the Federal Register on the proposed changes prior to the  Bureau’s issuance of the final rule. To describe the changes to how the Bureau will assure the quality of  population estimates updated by the challenge program, we reviewed the  Federal Register notice outlined earlier, and we interviewed Bureau  officials to identify additional quality assurance steps the Bureau intends  to implement. To examine the Bureau’s plans to use the types of local administrative  records currently used by the challenge program to improve the cost or  quality of the 2020 Decennial Census, we reviewed Bureau  documentation on research and testing of administrative records for the  2020 Census, as well as our prior reports on the Bureau’s research and  testing efforts.
Why GAO Did This Study

The Bureau's Population Estimates Challenge Program gives local governments the opportunity to challenge the Bureau's annual estimates of their population counts during the years between decennial censuses. Challenges rely on local administrative records, such as building and demolition permits. In addition to their role in the challenge program, these and national administrative records, such as tax data and Medicare records, could save the Bureau money if they are used to help build the Bureau's master address list, and reduce the need for certain costly and labor-intensive door-to-door visits among other things. GAO was asked to review changes to the challenge program and the Bureau's use of administrative records.
This report describes the changes to: (1) how local administrative records will be used in the challenge program; (2) how the Bureau will assure the quality of population estimates updated by the challenge program; and describes (3) what plans, if any, the Bureau has to use the types of local administrative records used for the challenge program to improve the cost or quality of the 2020 Decennial Census.
GAO reviewed documentary and testimonial evidence from Bureau officials and state and local data experts. Additionally, GAO interviewed Bureau officials to identify changes to the challenge program and reviewed documentation on the challenge program's quality assurance processes. GAO provided a draft of this report to the Department of Commerce. In response the Bureau provided technical comments, which were incorporated as appropriate.

What GAO Found

The Census Bureau (Bureau) issued significant changes to rules governing the records that communities use to challenge the Bureau's population estimates. Previously, the Bureau routinely accepted all challenges, largely without regard to the data sources cited or provided so long as they supported the calculations and covered the appropriate reporting periods. According to Bureau officials, these changes are based on research that shows that estimates based on some methods and records (e.g., births, deaths, and migration) are substantially more accurate than estimates based on others. Among other changes, the Bureau modified procedures so that challenges by subcounty governments to the Bureau's estimates of people living in housing units will no longer affect countylevel population estimates. Moving forward, any such challenge resulting in an increase in the estimate of a subcounty population will be offset by a downward revision to the population estimate of all other communities in the same county. Also, the Bureau plans to routinely review population challenges in light of each community's population growth trend.Corroborating data will be required for challenges inconsistent with the trend.
Challenge program officials told GAO that in the past the program focused quality assurance on (1) reviewing the calculations in the documentation submitted by local governments as part of challenge submissions and (2) checking documents and calculations for internal consistency. Moving forward, the Bureau is preparing a quality assurance plan for Bureau staff who review challenges to better ensure proper handling and processing of challenges, as well as the review of calculations.
The Bureau's 2020 research and testing program is exploring the use of local administrative records for the 2020 Census, such as those used in the challenge program, but this effort is a lower priority than research on the use of national records, in part because national administrative records show greater promise than local records for controlling costs. Bureau officials said local records show the most promise for supporting the development of the 2020 address list. Specifically, the Bureau is exploring how it can use local records to more seamlessly and continually update address lists and maps, rather than waiting to receive such information as part of a one-time decennial update. Bureau officials stated that it is important to continue research on local records because they may be helpful in targeting decennial operations to hard-to-count groups or those in certain geographic areas. However, the results of 2010 Census research and testing on national records have led Bureau officials to conclude that continuing research on national records should be a higher priority.