2010 Census
Follow-up Should Reduce Coverage Errors, but Effects on Demographic Groups Need to Be Determined Gao ID: GAO-11-154 December 14, 2010The U.S. Census Bureau (Bureau) puts forth tremendous effort to conduct a complete and accurate count of the nation's population and housing; yet some degree of error in the form of persons missed, duplicated, or counted in the wrong place is inevitable due to the complexity in counting a large and diverse population. The Bureau designed two operations, Coverage Follow-up (CFU) and Field Verification (FV), to reduce certain types of counting, or coverage, errors in the 2010 Census. GAO was asked to assess (1) the extent to which the Bureau completed CFU and FV on schedule and within estimated cost and (2) the implications of their key design elements for improving coverage. GAO reviewed Bureau evaluations, planning, and other documents on CFU and FV, and prior GAO work, and interviewed Bureau officials.
The Bureau completed CFU and FV on schedule and within budget. FV cost $21 million (about 38 percent less than estimated) and CFU cost about $267 million (about 2 percent less than estimated). These operations followed up on potential errors on census returns or lists of addresses after census data had been initially collected. Their completion provided follow-up data used by subsequent data processing that removed errors from the official census tabulations. Three of the Bureau's key CFU design elements will likely improve overall census accuracy, but their effect on undercounts of different demographic groups is not clear. One key design element increased the number and types of follow-up cases. The Bureau expanded the scope of CFU from about 2 million households in the 2000 Census to more than 7 million in 2010. It also added 20 different types of households for potential follow-up. New types included households that reported members temporarily residing elsewhere, such as at college, in nursing homes, or in jail. According to the Bureau, the 2010 CFU operation should remove more than 2.7 million coverage errors from the census. Another key design element of CFU prioritized follow-up cases based on their likelihood to result in a census correction, which was a reasonable attempt to leverage the resources for the operation. However, the Bureau's evaluation plans, based on considerations of what may best reduce cost or increase accuracy in the future, do not link the demographic characteristics of households to how they responded to the additional questions or CFU results for those households. Therefore, it is unclear whether the prioritized follow-up will help reduce differences in the accuracy of census counts across demographic groups. Finally, CFU's design relied on a telephone-only approach to complete follow-up rather than personal visits. This limited costs, resulting in more follow-up and likely more coverage errors being removed from the census. But the telephone-only decision excluded about 700,000 households from CFU that could not be contacted by telephone. Prior Bureau experience indicates that some historically undercounted groups were less likely to be reachable by telephone, and more recent independent research suggests that trends in telecommunication usage may also make it harder to reach some demographic groups this way in the future. Yet the Bureau's evaluation plans do not include an assessment of either the usefulness of the telephone numbers it collected in reaching specific groups or the effect of these trends. Greater understanding of how best to reach different groups as well as the influence of trends on the effectiveness of CFU could help to control costs while working to further reduce differential undercounts. GAO recommends that the Secretary of Commerce direct the Bureau to assess (1) how well questions to help identify miscounted people on census forms helped reduce differences in the undercounts between demographic groups; (2) the degree to which telephone numbers led to completed contacts for households of various demographic characteristics; and (3) how trends in telecommunication usage and new technology may influence the effectiveness of CFU. The Secretary of Commerce concurred with our recommendations.
RecommendationsOur recommendations from this work are listed below with a Contact for more information. Status will change from "In process" to "Open," "Closed - implemented," or "Closed - not implemented" based on our follow up work.
Director: Robert N. Goldenkoff Team: Government Accountability Office: Strategic Issues Phone: (202) 512-2757GAO-11-154, 2010 Census: Follow-up Should Reduce Coverage Errors, but Effects on Demographic Groups Need to Be Determined
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United States Government Accountability Office:
GAO:
Report to Congressional Requesters:
December 2010:
2010 Census:
Follow-up Should Reduce Coverage Errors, but Effects on Demographic
Groups Need to Be Determined:
GAO-11-154:
GAO Highlights:
Highlights of GAO-11-154, a report to congressional requesters.
Why GAO Did This Study:
The U.S. Census Bureau (Bureau) puts forth tremendous effort to
conduct a complete and accurate count of the nation‘s population and
housing; yet some degree of error in the form of persons missed,
duplicated, or counted in the wrong place is inevitable due to the
complexity in counting a large and diverse population. The Bureau
designed two operations, Coverage Follow-up (CFU) and Field
Verification (FV), to reduce certain types of counting, or coverage,
errors in the 2010 Census. GAO was asked to assess (1) the extent to
which the Bureau completed CFU and FV on schedule and within estimated
cost and (2) the implications of their key design elements for
improving coverage.
What GAO Found:
The Bureau completed CFU and FV on schedule and within budget. FV cost
$21 million (about 38 percent less than estimated) and CFU cost about
$267 million (about 2 percent less than estimated). These operations
followed up on potential errors on census returns or lists of
addresses after census data had been initially collected. Their
completion provided follow-up data used by subsequent data processing
that removed errors from the official census tabulations.
Three of the Bureau‘s key CFU design elements will likely improve
overall census accuracy, but their effect on undercounts of different
demographic groups is not clear. One key design element increased the
number and types of follow-up cases. The Bureau expanded the scope of
CFU from about 2 million households in the 2000 Census to more than 7
million in 2010. It also added 20 different types of households for
potential follow-up. New types included households that reported
members temporarily residing elsewhere, such as at college, in nursing
homes, or in jail. According to the Bureau, the 2010 CFU operation
should remove more than 2.7 million coverage errors from the census.
Another key design element of CFU prioritized follow-up cases based on
their likelihood to result in a census correction, which was a
reasonable attempt to leverage the resources for the operation.
However, the Bureau‘s evaluation plans, based on considerations of
what may best reduce cost or increase accuracy in the future, do not
link the demographic characteristics of households to how they
responded to the additional questions or CFU results for those
households. Therefore, it is unclear whether the prioritized follow-up
will help reduce differences in the accuracy of census counts across
demographic groups.
Finally, CFU‘s design relied on a telephone-only approach to complete
follow-up rather than personal visits. This limited costs, resulting
in more follow-up and likely more coverage errors being removed from
the census. But the telephone-only decision excluded about 700,000
households from CFU that could not be contacted by telephone. Prior
Bureau experience indicates that some historically undercounted groups
were less likely to be reachable by telephone, and more recent
independent research suggests that trends in telecommunication usage
may also make it harder to reach some demographic groups this way in
the future. Yet the Bureau‘s evaluation plans do not include an
assessment of either the usefulness of the telephone numbers it
collected in reaching specific groups or the effect of these trends.
Greater understanding of how best to reach different groups as well as
the influence of trends on the effectiveness of CFU could help to
control costs while working to further reduce differential undercounts.
What GAO Recommends:
GAO recommends that the Secretary of Commerce direct the Bureau to
assess (1) how well questions to help identify miscounted people on
census forms helped reduce differences in the undercounts between
demographic groups; (2) the degree to which telephone numbers led to
completed contacts for households of various demographic
characteristics; and (3) how trends in telecommunication usage and new
technology may influence the effectiveness of CFU. The Secretary of
Commerce concurred with our recommendations.
View [hyperlink, http://www.gao.gov/products/GAO-11-154] or key
components. For more information, contact Robert Goldenkoff at (202)
512-2757 or goldenkoffr@gao.gov.
[End of section]
Contents:
Letter:
Background:
The Bureau Completed FV and CFU on Schedule and within Budget, but
Needs to Improve the Accuracy of Its Cost Estimates:
CFU Should Help Improve Overall Census Coverage, but Its Effect on
Different Demographic Groups May Not Be Uniform:
Conclusions:
Recommendations for Executive Action:
Agency Comments and Our Evaluation:
Appendix I: Comments from the Department of Commerce:
Related GAO Products:
Table:
Table 1: CFU Performance Exceeded Targets:
Figure:
Figure 1: The Bureau Used Probes on Census Questionnaires to Identify
Households with Possible Coverage Errors:
Abbreviations:
Bureau: U.S. Census Bureau:
CFU: Coverage Follow-up:
FV: Field Verification:
IT: information technology:
[End of section]
United States Government Accountability Office:
Washington, DC 20548:
December 14, 2010:
The Honorable Thomas R. Carper:
Chairman The Honorable John McCain:
Ranking Member:
Subcommittee on Federal Financial Management, Government Information,
Federal Services, and International Security:
Committee on Homeland Security and Governmental Affairs:
United States Senate:
The Honorable Darrell E. Issa:
Ranking Member:
Committee on Oversight and Government Reform:
House of Representatives:
The Honorable William Lacy Clay:
Chairman:
The Honorable Patrick T. McHenry:
Ranking Member:
Subcommittee on Information Policy, Census, and National Archives:
Committee on Oversight and Government Reform:
House of Representatives:
The U.S. Census Bureau (Bureau) puts forth tremendous effort to
conduct a complete and accurate count of the nation's population and
housing; nonetheless, some degree of error in the form of persons
missed, duplicated, or counted in the wrong place during the decennial
census is inevitable due to the complexity of counting a large and
diverse population.
The Bureau estimates that the 2000 Census undercounted certain
population groups, including minorities, renters, and children, but
somewhat overcounted the population as a whole. An undercount occurs
when the census misses an individual who should have been enumerated;
an overcount occurs when an individual is counted in error.
Differences among undercounts of ethnic, racial, and other groups are
referred to as "differential undercounts," which may have implications
for political representation and other uses of census data. In an
effort to improve accuracy and reduce differential undercounts of the
population in 2010, the Bureau conducted the Coverage Follow-up (CFU)
and Field Verification (FV) operations, two programs intended to clean
up possible errors identified after households provided their census
responses. During CFU, a contractor telephoned certain households in
an attempt to determine if someone had been miscounted, such as when
the number of people reported living in a household did not match the
number of people whose name and demographic information was included
on the household's census form. During FV, the Bureau visited
addresses that had been provided by persons that thought they had been
missed by the census and that did not match the Bureau's master
address list. From the 2000 Census, the Bureau expanded CFU and
allocated more than $200 million in additional funds--including $30
million provided by the American Recovery and Reinvestment Act of 2009
[Footnote 1]--which allowed the Bureau to include an additional 1.1
million households within the scope of CFU.
After reviewing the status of CFU in 2008, we recommended that the
Bureau submit its plans for CFU to Congress and decide how it would
conduct the operation.[Footnote 2] The Bureau did so and completed CFU
in August 2010 and FV in September 2010. As requested, for this review
we examined (1) the extent to which FV and CFU were completed on
schedule and within cost estimates, and (2) key design elements of CFU
and FV, the implications for those design elements on improving
coverage, and possible lessons learned to the extent similar efforts
are used in the 2020 Census. This report is one of three we are
releasing today.[Footnote 3] The other reports focus on the Bureau's
efforts to reach out to and enumerate hard-to-count populations, and
efforts to complete other key census-taking activities. Both reports
identify preliminary lessons learned, as well as potential focus areas
for improvement.
To meet both objectives, we assessed Bureau planning, testing, and
schedule documents and interviewed Bureau officials to supplement and
verify the currency and relevance of documentation obtained. For the
first objective we also assessed the performance of CFU and FV against
the cost, timeliness, and other metrics the Bureau used to monitor the
operations. Additionally, for the second objective we reviewed our
past reports and Bureau literature on known limitations of follow-up
methods to identify key design elements and their implications. We
also assessed Bureau study and evaluation plans. We conducted this
performance audit from March 2010 to December 2010 in accordance with
generally accepted government auditing standards. Those standards
require that we plan and perform the audit to obtain sufficient,
appropriate evidence to provide a reasonable basis for our findings
and conclusions based on our audit objectives. We believe that the
evidence obtained provides a reasonable basis for our findings and
conclusions based on our audit objectives.
Background:
To help ensure a complete count, the Bureau had a number of operations
aimed at capturing census data from people and households that
otherwise might have been missed by the census. For example, the Be
Counted program was designed to make special census questionnaires
available to those who may not have received one, including people who
do not have a usual residence, such as transients, migrants, and
seasonal farm workers. The questionnaires were placed in over 38,000
locations across the country, including libraries, convenience stores,
and other places people might frequent. The Bureau conducted FV to
verify the existence of new addresses provided on these questionnaires
and through other sources that were not already on the Bureau's master
address list. The procedures enumerators followed to verify addresses
in 2010 were largely similar to those used in the 2000 Census. In
2000, the Bureau visited nearly 900,000 addresses as part of its FV
operation, verifying the addition of over 450,000 addresses to its
address list.
To help ensure accuracy in the population count in 2000, the Bureau
used telephone interviews in another operation to follow up with two
types of household responses: households too large to include all
their members on the form and households with apparent discrepancies
on their questionnaires, such as when the number of people reported in
the household population box does not match the number of people whose
name and demographic information is included on the form. The Bureau
placed calls to these households to determine if additional persons
might have been missed (undercounted), if persons might have been
counted in error (overcounted), or if persons might have been counted
in the wrong place (possibly an overcount in one place and an
undercount in another). The Bureau followed up on over 2.5 million
households at a cost of approximately $67 million, resulting in over
152,000 people being added to the official census count and
approximately 258,000 others being removed.
In response to Census 2000 experiences and in order to help achieve a
Bureau goal of reducing differential undercounts, the Bureau added
questions to the 2010 Census questionnaire to better identify
potential coverage problems. These additional questions--called
coverage probes--were to help identify households that may have
omitted (undercounted) persons, due to familial relationships such as
young children and extended family residing in the household but not
reported on the census questionnaire due to space limitations, or
households that may have counted persons more than once (overcounted),
due to situations where members spent time elsewhere, such as
relatives living in nursing homes or college dormitories. The
resulting coverage probes used on the 2010 Census questionnaire are
shown below in figure 1.
Figure 1: The Bureau Used Probes on Census Questionnaires to Identify
Households with Possible Coverage Errors:
[Refer to PDF for image: illustration]
Informational copy of a Census Questionnaire.
Source: GAO Presentation of Census Bureau Information.
[End of figure]
The Bureau Completed FV and CFU on Schedule and within Budget, but
Needs to Improve the Accuracy of Its Cost Estimates:
FV Was Completed on Schedule and Well Under Budget:
The 2010 FV operation began July 21, 15 days early, and finished on
schedule on September 8, 2010. During that time, the Bureau visited
nearly 456,000 addresses. The Bureau's preliminary results show that
about 49 percent of those addresses were verified as valid housing
units, 33 percent did not exist, and 18 percent were duplicates. The
Bureau expects to report the final results in its formal evaluations
of FV, planned for release in July 2011.
Completing FV on schedule was commendable, given that the Bureau had
to make several late changes to the design of the operation as part of
a contingency plan. Before beginning the FV operation, the information
technology (IT) system the Bureau had expected to use to support the
operation experienced testing and development delays. Furthermore, the
Bureau was experiencing difficulty with this system being used to
support other major census field operations. Therefore the Bureau
developed and implemented a contingency plan, which substituted a
modified version of the IT system used to support the 2010 Census
Coverage Measurement operations and the IT system used for the 2000
Census, changed some related procedures for shipping workload
materials, and significantly expanded the quality-assurance program to
mitigate the risk of introducing additional changes to the contingency
IT system. The Bureau attributes its ability to complete FV on time to
its aggressive monitoring of the risk that IT systems might not be
ready, its having identified a contingency IT system in advance, and
the small scale of the FV operation compared to other census field
operations, which allowed for the rapid adoption of alternative
procedures. The Bureau's timely response to IT system delays
demonstrates the benefits of the Bureau having developed risk
mitigation plans for significant risks, as we have recommended before.
[Footnote 4]
The Bureau completed FV at a cost of $21 million, 38 percent lower
than the $33.8 million estimated for the operation. Bureau officials
are still researching why costs were lower than expected, but their
preliminary analysis attributes cost savings to increased productivity
and reduced operational inputs, such as training hours and mileage.
The final cost of the operation was unexpected considering that the
Bureau estimated that the late changes made by the contingency plan
would increase the cost per case and increase total costs by nearly
$15 million for the estimated workload. Under the Bureau's original
calculation, adding the contingency plan raised the estimated cost-per-
case to about $74, far more than the $53 per case assumed in the
initial budget estimate or the $46 per case reported at the end of the
operation. The Bureau has not attempted to separately identify how
much of the final cost per case increase was attributable to the
contingency plan or other factors.
Achieving cost savings is a positive development. However, our prior
work has highlighted the need for the Bureau to develop more accurate
and rigorous cost estimates for census operations.[Footnote 5] A high-
quality cost estimate is the foundation of a good budget, providing an
estimate of the funding required to efficiently execute a program.
Additionally, according to our Cost Assessment Guide, a cost estimate
should be a "living" document that is continually updated as actual
costs begin to replace original estimates, so that it remains relevant
and current.[Footnote 6] We have previously recommended[Footnote 7]
that the Bureau document where actual costs differ from those
estimated to help document lessons learned and the basis for changes
made to assumptions used. The Bureau updated its cost estimate for FV
as its estimated workload changed and when it considered adoption of
the contingency plan. However, moving forward it will be important to
be able to explain the variation in its cost estimates.
CFU Was Completed on Schedule and Exceeded Performance Targets:
The 2010 CFU operation began and finished on schedule, ensuring that
CFU data were available for subsequent data processing. From April 11
to August 14, Bureau contractors telephoned nearly 7.4 million
households, of which 4.9 million (66 percent) were complete
interviews, meeting their estimated workload target. The Bureau
expects to be able to report an analysis of the effect of CFU on
census coverage in the spring of 2011.
The Bureau completed CFU at an estimated cost of $267 million, about 2
percent less than the initial cost estimate for the operation. As
shown in table 1 below, the Bureau completed a slightly higher
percentage of cases it attempted and spent on average less time on the
phone completing each interview than expected.
Table 1: CFU Performance Exceeded Targets:
Performance measure: Case-completion rate (percent);
Target: 65;
Actual: 66.
Performance measure: Cases completed per hour per interviewer;
Target: 2.36;
Actual: 2.35.
Performance measure: Average interviewer score for quality assurance
(percent);
Target: 97;
Actual: 99.
Performance measure: Average call time (seconds);
Target: 249;
Actual: 208.
Source: Census Bureau.
Note: Data are from Census Bureau management reporting.
[End of table]
Given mandated deadlines that the Bureau faces for delivering census
tabulations, completing field data collection including CFU and FV on
schedule was crucial for subsequent processing activities to proceed
and be completed on schedule.
CFU Should Help Improve Overall Census Coverage, but Its Effect on
Different Demographic Groups May Not Be Uniform:
Three design decisions for the 2010 CFU operation should improve
overall census accuracy. These decisions include:
* expanding the scope of the 2010 CFU operation compared to its 2000
operation,
* prioritizing types of follow-up cases, and:
* contacting identified CFU households using only the telephone.
The Bureau's Increase in the Number and Types of CFU Cases Should
Improve Overall Census Accuracy:
A key design decision the Bureau made for the 2010 CFU was to expand
the scope of its coverage follow-up operation from 2000 to follow up
on additional types of cases that it believed would help reduce the
differential undercount. While continuing to follow up on the two
types of cases that constituted the 2000 follow-up operation--large
households and those with apparent count discrepancies--the Bureau
identified 20 additional types of cases potentially to cover in 2010.
One of these types of cases came from the use of administrative
records from other federal sources, such as demographic information
and addresses of families receiving tenant subsidies from an
information system at the Department of Housing and Urban Development,
to identify persons associated with a household's address who might
have been omitted from the household's census form. Most of the
additional types of cases were identified from responses to the new
coverage probes on the census questionnaire discussed earlier.
Additional types included households with responses indicating
household members present who may not have been recorded on the
initial census form, such as newborn babies, foster children,
roommates or live-in babysitters, or household members who may have
lived or stayed at more than one place, such as college students or
nursing-home residents.
Expanding the scope of the 2010 CFU increased the number of cases the
Bureau followed up on from about 2.5 million cases in 2000 to about 8
million cases in 2010. According to the Bureau, the 2010 CFU operation
should result in more than 2.9 million coverage errors being removed
from the census, including overcounts and undercounts, compared to
more than 400,000 coverage errors being removed in 2000. The more
coverage errors are removed from the official census count, the more
the overall accuracy of the census is improved.
The Effect of the Bureau's Prioritization of Coverage Follow-up on
Differential Undercounts Is Not Clear:
A second key design decision the Bureau made for CFU was to prioritize
the types of cases it would follow up on, likely increasing the
overall number of coverage errors corrected but possibly affecting
demographic groups differently. The Bureau had to prioritize follow-up
cases, since the expansion of the CFU scope resulted in an estimated
22.5 million potential CFU cases, far exceeding what its time and
budget for the 2010 CFU operation would permit. Bureau planning
documents indicate that along with the extra time needed to pursue
22.5 million cases, it would have cost approximately $800 million more
to complete all of the possible follow-up cases.
In April 2010, the Bureau formally documented its decision to
prioritize follow-up based on cost and estimates of the number of
corrections that would result from each type of case, and documented
which cases it planned to include in follow-up. The Bureau estimated
that in addition to households with apparent discrepancies on their
questionnaires and households too large to include all their members
on the form--the two types of cases it focused on in 2000--it would
complete follow-up on 8 of 20 additional types of cases. However, due
to a combination of higher call efficiency and lower-than-expected
workloads for some of the selected types of cases, in the end the
Bureau was able to follow up on an additional three types of CFU cases.
The Bureau's decisions to expand the scope of CFU and prioritize the
CFU cases will likely result in a greater number of coverage errors
being removed from official census tabulations than were removed in
2000, increasing CFU's effectiveness in improving overall census
accuracy in 2010. Prioritization of the CFU cases to contact was a
reasonable attempt to leverage the resources and time available for
the operation. However, because the specific coverage probes the
Bureau used on census questionnaires do not clearly map to specific
demographic groups, the extent to which the prioritized follow-up will
help achieve the Bureau's goal of reducing the differential undercount
is unclear. For example, one of the Bureau's priorities for follow-up
was households indicating that persons may have been included who
should have been counted elsewhere, such as persons in jail, in
college, or in the military. Among the types that the Bureau did not
follow up on were households that reported persons who were sometimes
living elsewhere seasonally or as part of custody-sharing
arrangements. The demographic characteristics of the people covered by
each of these probes are not likely to be the same as the general
population. Thus, following up on one set of cases but not others will
likely have a different, though unknown, effect on particular
demographic groups.
The Bureau acknowledges that, in so far as households in certain
groups are not contacted by telephone but have coverage errors, there
would likely be a smaller improvement in coverage for those
demographic groups. Yet Bureau officials maintain that since it would
be difficult to design follow-up based directly on household
characteristics such as race and Hispanic origin, relying on situation-
and relationship-based probes on census questionnaires--such as the
Bureau did in 2010--may be the most effective way to identify coverage
follow-up cases. To that end, the Bureau has 2010 data on how each
household responded to each coverage probe and the demographics of
each household, and will ultimately know which probes led to
corrections of census coverage errors. The Bureau plans to report the
demographic groups for which CFU identified corrections as part of its
formal assessment of CFU, but that assessment does not include a link
between the results for each probe and historically undercounted
groups. Bureau officials have explained that its evaluation choices
are driven by consideration of the best value to the decennial census
in terms of informing possible cost benefit analyses and improvements
to accuracy, and can change in response to new information the Bureau
may obtain. Linking these data from 2010 CFU could help the Bureau
decide which of the probes and priorities best helped the Bureau both
improve overall accuracy and reduce the differential undercount, and
better inform the Bureau decision making on the use of coverage probes
for 2020.
The Effect of the Bureau's Telephone-Only Approach on Differential
Undercounts Is Not Clear:
A third key design decision the Bureau made for CFU was to rely solely
on telephone interviews rather than use personal visits to contact
households during the 2010 CFU operation. For those households the
Bureau can reach by telephone, this decision should have enabled the
Bureau to reduce many more census errors, because it allowed the
Bureau to follow up with more households than it could have with
personal visits using the same level of funding. A Bureau evaluation
of its 2000 coverage follow-up activities suggested that personal
visits be used for households for which the Bureau has no valid
telephone number, noting that traditionally undercounted groups, such
as renters and certain minority groups, were less likely to have valid
phone numbers. Yet personal visits are significantly more expensive
than telephone calls, costing about $71 per case compared to about $19
per case for telephone calls, according to Bureau results from a 2006
census test of CFU.
To increase the effectiveness of its telephone-only approach, the
Bureau implemented several specific recommendations from its
evaluation of the 2000 follow-up operation, including the use of a
commercial database to assist with identifying the telephone numbers
that were invalid or missing for CFU cases. Bureau officials believe
that adopting these recommendations led to significant increases in
the effectiveness of telephone follow-up, with reported response rates
to telephone calls conducted as part of 2010 Census tests of 63
percent in 2004, 80 percent in 2005, and 78 percent in 2006. For 2010
CFU, Bureau management reporting indicates that the response rate
exceeded its target goal of 65 percent.
The Bureau's decision to rely solely on telephone calls and related
measures to complete CFU resulted in lower cost and more effective
follow-up, and should contribute to a greater number of coverage
errors being removed from official census tabulations compared to
2000. While these design decisions helped increase overall census
accuracy, their effect on the Bureau's goal to reduce the differential
undercount is less clear. This is because the Bureau excluded from CFU
any household for which it did not obtain a useable telephone number.
A useable phone number was obtained either from the respondent's
return and could be a wireless or landline telephone number or through
a telephone number look-up that resulted in the retrieval of landline
numbers only. This is potentially problematic for two reasons.
First, current research indicates that there are significant
differences between households that use only wireless telephones and
those that have landline telephones, with groups of households with
high wireless-only usage being part of historically undercounted
populations.[Footnote 8] According to our analysis of Bureau
management reporting, the Bureau excluded about 700,000 households
from follow-up because it lacked a usable contact telephone number.
The Bureau relied only on landline telephone numbers from its
commercial database, due to concerns about not knowing the geographic
location of wireless phones it might dial and the possible financial
burden on wireless customers from unsolicited calls. The Bureau did
not immediately know which household-provided numbers were wireless,
so it had rules concerning when calls could be made, to restrict calls
to local times appropriate for the location of addresses provided. The
Bureau has not attempted to track how many of the telephone numbers it
called or excluded from follow-up were wireless numbers, what types of
CFU cases they were for, or what the demographic characteristics of
these households might be. According to the Bureau, it has asked the
contractor that carried out the telephone calls for the Bureau to
report the disposition of cases where a number was found during look-
up as part of the contractor's forthcoming assessment. Future Bureau
decisions about how to contact households for follow-up can be better
informed if the Bureau strengthens its understanding of how different
sources of contact information can affect its goal to reduce the
differential undercount.
Furthermore, trends regarding the use of wireless telephones indicate
that some households within hard-to-count populations may be harder to
contact in the future using landline telephone operations. For
example, a recent Centers for Disease Control and Prevention study
shows that wireless-only households has more than doubled between
January 2006 and December 2009 from about 11 percent to more than 24
percent of the nation's households. And in May 2010, the Pew Research
Center found that wireless-only adults pose a significant challenge to
data collection by telephone, because such adults are substantially
different demographically from those reached on a landline phone.
According to the Pew Research Center, wireless-only adults tend to be
young, single, renters, and with lower income. This research also
found that minorities made up a larger share of the wireless-only
group with far more Hispanics, African-Americans, and people of other
or mixed racial backgrounds than those with landline telephones. Such
trends could pose a challenge to possible future Bureau reliance on
telephone-based contacts intended to help improve census coverage of
such demographic groups to the extent they do not provide their
telephone numbers on census questionnaires. Broader ongoing shifts in
the use of other telecommunications, including a variety of social
media, may also influence the relative effectiveness of strategies
relying on telephone communication.
Conclusions:
Overall, the Bureau generally implemented FV and CFU on schedule and
under budget, which is a noteworthy accomplishment given the inherent
challenges of conducting a cost-effective census. The Bureau also
updated its cost estimates for FV periodically as its estimated
workload for FV evolved, and adopted design changes for CFU that
likely contributed significantly to improving the overall accuracy of
the census. At the same time, the Bureau's experience in implementing
these two operations highlights additional actions that may improve
the Bureau's understanding of the effectiveness of CFU in reducing
differential undercounts and help improve planning for 2020 to the
extent that the Bureau conducts such operations as part of the next
decennial.
First, our previous work has highlighted the importance of accurate
and rigorous cost estimates; thus, it will be important for the Bureau
to assess the factors that led to significant variance in cost
estimates for FV. Knowing this will allow the Bureau to develop more
accurate cost estimates in the future, and will help the Bureau focus
on cost containment as it prepares for the 2020 Census. We are not
making recommendations at this time regarding the Bureau's cost
estimation methods, as we have already done so in a previous report.
[Footnote 9] The Bureau agreed with those recommendations at that time
and has begun implementing them.
Second, given the research and testing of coverage probes leading up
to their use in 2010, it will be important for the Bureau to assess
the degree to which the coverage probes helped address the
differential undercount. This will help the Bureau understand whether
the probes the Bureau prioritized for follow-up worked as intended and
could help the Bureau determine which probes or other follow-up
procedures to use in the future to improve census accuracy.
Third, it will be important for the Bureau to determine the
effectiveness of the phone numbers it obtained from census returns or
its commercial database in making contact with households of different
follow-up and demographic groups. The decision to rely solely on
telephone calls and no personal visits involved an implicit trade-off
between the opportunity for cost savings with improved overall census
accuracy and an opportunity possibly to help reduce historic
differential undercounts. If the Bureau better understood the
demographic composition of those for whom it did and did not obtain
telephone numbers, and for whom it was and was not successful in
reaching by phone, it could better determine the effect of this design
decision on differential undercounts. Also, better knowledge of how
best to reach different groups could help identify effective sources
of contact information or strategies for using them for future
censuses, further helping to control costs while still working to
address differential undercounts.
Finally, whether it is a trend of households moving away from reliance
on landlines, or other possible emerging trends related to growth in
other modes of communication and new technology, the Bureau's future
design decisions will benefit from tracking and assessing the
implications of such trends and leveraging or mitigating their effect
where possible. For example, under a scenario where the Bureau
continues to rely on telephones for contacting households, the Bureau
might need to adopt strategies for increasing the number of usable
telephone numbers provided by census respondents or revisit its
specific rules concerning when to dial numbers. Moving forward, it
will be important for the Bureau to identify how rapid changes in
technology and the public's use of them may affect the effectiveness
of its efforts to improve census accuracy, both overall and in terms
of reducing differential undercounts.
Recommendations for Executive Action:
We recommend that the Secretary of Commerce require the Director of
the U.S. Census Bureau to take the following three actions to improve
the Bureau's planning for the 2020 Census:
To help the Bureau decide which coverage probes, if any, to use and
prioritize for future follow-up efforts, assess the extent to which
historically overcounted and undercounted demographic groups responded
to the probes the Bureau followed up on and determine the
effectiveness of specific probes in reducing differential undercounts.
* To support the Bureau's efforts to control costs while improving
census accuracy, determine the demographic characteristics of the
households for which it did and did not obtain telephone numbers and,
to the extent feasible, assess the degree to which the telephone
numbers were usable and led to completed contacts for households of
various follow-up groups and demographic characteristics.
* To ensure that the design of future follow-up efforts is effective
in improving census coverage, assess the implications that trends in
landline and wireless usage and other modes of communication and new
technology may have both on the design decisions for future CFU-like
operations and on their effectiveness in improving census coverage in
terms of both overall census accuracy and differential undercounts.
Agency Comments and Our Evaluation:
The Secretary of Commerce provided written comments on a draft of this
report on December 1, 2010. The comments are reprinted in appendix I.
The Department of Commerce agreed with the overall findings and
recommendations and appreciated our efforts in helping the Bureau
develop a successful evaluation plan for the 2020 Census. The
department also included comments from the Bureau on certain
statements in the report.
The Bureau commented on our discussion of its initial estimate that
the contingency plan it adopted would increase the cost of FV. The
Bureau commented that its initial estimate that the contingency plan
would increase the cost of FV by $15 million was based on estimated
workloads, that the final FV workload was much smaller, and that it
had not attempted to reestimate the cost effect of the contingency
plan separately. We revised the text to more fully reflect that the
estimated increase was based on estimated workload, and emphasized the
changes in "cost per case," which better reflects the effect on cost
of changes in workload.
The Bureau also commented on our discussion of telecommunication
trends and the Bureau's need to understand how different sources of
contact information can affect its goal to reduce the differential
undercount. The Bureau agreed that the trend toward wireless
communication needs more attention in the future and described how it
had not yet collected certain data that might be needed to carry out
evaluation of the type we recommended. According to our analyses, the
additional data are easily obtained. We revised the text to point more
specifically to the type of data that could help the Bureau with
future decisions about how to reach historically undercounted groups.
We are sending copies of this report to the Secretary of Commerce, the
Director of the U.S. Census Bureau, and interested congressional
committees. The report also is available at no charge on GAO's Web
site at [hyperlink, http://www.gao.gov].
If you have any questions about this report please contact me at (202)
512-2757 or goldenkoffr@gao.gov. Contact points for our Offices of
Congressional Relations and Public Affairs may be found on the last
page of this report. Key contributors to this report were Ty Mitchell,
Assistant Director; Mark Abraham; Sara Daleksi; Ron Fecso; Andrea
Levine; Donna Miller; Jessica Thomsen; Jonathon Ticehurst; Holly
Williams; and Katherine Wulff.
Signed by:
Robert Goldenkoff:
Director: Strategic Issues:
[End of section]
Appendix I: Comments from the Department of Commerce:
Note: Page numbers in the draft report may differ from those in this
report.
The Secretary Of Commerce:
Washington, D.C. 20230:
December 1, 2010:
Mr. Robert Goldenkoff:
Director:
Strategic Issues:
United States Government Accountability Office:
Washington, DC 20548:
Dear Mr. Goldenkoff:
The U.S. Department of Commerce appreciates the opportunity to comment
on the draft report by the United States Government Accountability
Office (GAO), entitled "2010 Census: Follow-up Should Reduce Coverage
Errors, but Effects on Demographic Groups Need to be Determined" (GA0-
11-154). The Department's comments on this report are enclosed.
Enclosure
Sincerely,
Signed by:
Gary Locke:
Enclosure:
[End of letter]
U.S. Department of Commerce Comments on the United States Government
Accountability Office Draft Report, Entitled "2010 Census: Follow-up
Should Reduce Coverage Errors, but Effects on Demographic Groups Need
to be Determined" (GA0-11-154); December 2010.
The U.S. Department of Commerce thanks the U.S. Government
Accountability Office (GAO) for its efforts in examining the 2010
Census Coverage Follow-up (CFU) and Field Verification (FV)
operations. The GAO assessed the Census Bureau's performance in
completing these operations on schedule and within budget and
evaluated their efficacy in accurately reducing coverage errors.
We have no fundamental disagreements with the overall findings or with
the recommendations regarding items to be studied for the 2020 Census.
However, the Census Bureau provides the following comments about
statements and conclusions in this report.
* Page 7, first full paragraph: "The final cost of the operation was
unexpected considering that the Bureau estimated that the late changes
made by the contingency plan would increase costs by nearly $15
million."
Census Bureau response: Prior to the operation, the Census Bureau used
a preliminary workload estimate to roughly calculate operational costs
under the contingency plan. Using the preliminary workload figures,
the estimated impact was a $15 million increase in the budget. The
actual workload was much lower than originally estimated. The total
budget for the entire operation was only $33.8 million, including any
impact of the contingency approach. The Census Bureau did not separate
out the costs associated with the contingency plan, though clearly it
would be less than the earlier $15 million estimate because the actual
workload was much smaller than what was assumed when constructing that
earlier impact estimate.
* Page 16, paragraph continued from page 15: "The Bureau has not
attempted to track how many of the households it called or excluded
from follow-up had wireless numbers, what types of CFU cases they
were, or what the demographic characteristics of these households
might be."
Census Bureau response: The Census Bureau agrees the trend towards
wireless numbers (and away from landlines) needs more attention in the
future for operations like CFU that depend entirely on telephone
interviews. Unfortunately, the Census Bureau did not collect the data
during the 2010 Census CFU operation that would be needed to conduct
the analysis GAO recommends. The numbers that we called during CFU
came primarily from the telephone numbers that people provided to us
on their 2010 Census questionnaire. Some of the numbers would have
been for landline telephones, and some numbers would have been for
wireless telephones. However, we didn't collect the information to
know which numbers corresponded to which devices, or whether people we
called on a landline telephone also had a wireless telephone number.
For the 2020 Census research and testing program, the Census Bureau is
committed to closely following and studying these trends towards
wireless communications.
In conclusion, we acknowledge the GAO's extensive work in reviewing
these activities, and we appreciate its ongoing efforts to help us
develop a successful evaluation plan for the 2020 Census.
[End of section]
Related GAO Products:
2010 Census: Key Efforts to Include Hard-to-Count Populations Went
Generally as Planned; Improvements Could Make the Efforts More
Effective for Next Census. [hyperlink,
http://www.gao.gov/products/GAO-11-45]. Washington, D.C.: December 14,
2010.
2010 Census: Data Collection Operations Were Generally Completed as
Planned, but Long-standing Challenges Suggest Need for Fundamental
Reforms. [hyperlink, http://www.gao.gov/products/GAO-11-193].
Washington, D.C.: December 14, 2010.
2010 Census: Census Bureau Continues to Make Progress in Mitigating
Risks to a Successful Enumeration, but Still Faces Various Challenges.
[hyperlink, http://www.gao.gov/products/GAO-10-132T]. Washington,
D.C.: October 7, 2009.
GAO Cost Estimating and Assessment Guide: Best Practices for
Developing and Managing Capital Program Costs. [hyperlink,
http://www.gao.gov/products/GAO-09-3SP]. Washington, D.C.: March 2009.
2010 Census: The Bureau's Plans for Reducing the Undercount Show
Promise, but Key Uncertainties Remain. [hyperlink,
http://www.gao.gov/products/GAO-08-1167T]. Washington, D.C.: September
23, 2008.
2010 Census: Census Bureau Should Take Action to Improve the
Credibility and Accuracy of Its Cost Estimate for the Decennial
Census. [hyperlink, http://www.gao.gov/products/GAO-08-554].
Washington, D.C.: June 16, 2008.
2010 Census: Bureau Needs to Specify How It Will Assess Coverage
Follow-up Techniques and When It Will Produce Coverage Measurement
Results. [hyperlink, http://www.gao.gov/products/GAO-08-414].
Washington, D.C.: April 15, 2008.
Information Technology: Census Bureau Needs to Improve Its Risk
Management of Decennial Systems. [hyperlink,
http://www.gao.gov/products/GAO-08-79]. Washington, D.C.: October 5,
2007.
[End of section]
Footnotes:
[1] Pub. L. No. 111-5, div. A, tit. II, 123 Stat. 115, 127.
[2] GAO, 2010 Census: Bureau Needs to Specify How It Will Assess
Coverage Follow-up Techniques and When It Will Produce Coverage
Measurement Results, [hyperlink,
http://www.gao.gov/products/GAO-08-414] (Washington, D.C.: Apr. 15,
2008).
[3] GAO, 2010 Census: Key Efforts to Include Hard-to-Count Populations
Went Generally as Planned; Improvements Could Make the Efforts More
Effective for Next Census, [hyperlink,
http://www.gao.gov/products/GAO-11-45] (Washington, D.C.: Dec. 14,
2010) and GAO, 2010 Census: Data Collection Operations Were Generally
Completed as Planned, but Long-standing Challenges Suggest Need for
Fundamental Reforms, [hyperlink,
http://www.gao.gov/products/GAO-11-193] (Washington, D.C.: Dec. 14,
2010).
[4] GAO, Information Technology: Census Bureau Needs to Improve Its
Risk Management of Decennial Systems, [hyperlink,
http://www.gao.gov/products/GAO-08-79] (Washington, D.C.: Oct. 5,
2007).
[5] GAO, 2010 Census: Census Bureau Should Take Acton to Improve the
Credibility and Accuracy of Its Cost Estimate for the Decennial
Census, [hyperlink, http://www.gao.gov/products/GAO-08-554]
(Washington, D.C.: June 16, 2008).
[6] GAO, GAO Cost Estimating and Assessment Guide: Best Practices for
Developing and Managing Capital Program Costs, [hyperlink,
http://www.gao.gov/products/GAO-09-3SP] (Washington, D.C.: March 2009).
[7] [hyperlink, http://www.gao.gov/products/GAO-08-554].
[8] National Center for Health Statistics, Wireless Substitution:
Early Release of Estimates from the National Health Interview Survey,
July-December 2009 (May 2010). Pew Research Center, Assessing the Cell
Phone Challenge to Survey Research in 2010 (May 2010).
[9] [hyperlink, http://www.gao.gov/products/GAO-08-554].
[End of section]
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