In October 2017, the Department of Commerce updated its cost estimate for the 2020 Census to reach $15.6 billion, a 27 percent increase on the estimate the agency offered in 2015.
According to a GAO report publicly released Sept. 17, the Census Bureau has gotten better at estimating costs, but the agency still needs to do more to meet reliability standards for its estimates.
“While improvements have been made, the Bureau’s October 2017 cost estimate for the 2020 Census does not fully reflect all the characteristics of a reliable estimate,” the report said.
“Specifically, for the characteristic of being well-documented, GAO found that some of the source data either did not support the information described in the cost estimate or was not in the files provided for two of its largest field operations.”
Some experts argued that the confidentiality of the Census will keep non-citizens responding, while others said a lack of government trust will depress response numbers.
According to the report, changes in the assumed response rate to the census, an improved ability to quantify risk and the costs for IT components of the census were central contributors to the cost estimate changes from 2015 to 2017.
GAO defined four characteristics of a reliable cost estimate: well-documented, accurate, credible and comprehensive.
“To be considered reliable, a cost estimate must meet the criteria for each of the four characteristics outlined in our Cost Estimating and Assessment Guide. According to our analysis, a cost estimate is considered reliable if the overall assessment ratings for each of the four characteristics are substantially or fully met,” the report said.
The Census Bureau’s 2017 estimate met or substantially met the standards for accuracy, credibility and comprehensiveness, but only partially met the standard for documentation, because some documentation was missing, inconsistent or difficult to understand.
“Cost estimates are considered valid if they are well-documented to the point they can be easily repeated or updated and can be traced to original sources through auditing, according to best practices,” the report said.
“Failure to document an estimate in enough detail makes it more difficult to replicate calculations, or to detect possible errors in the estimate; reduces transparency of the estimation process; and can undermine the ability to use the information to improve future cost estimates or even to reconcile the estimate with another independent cost estimate.”
GAO did not make any new recommendations in the report, but reiterated an earlier recommendation that the secretary of Commerce direct the Bureau to take steps to ensure that cost estimates meet the four GAO characteristics.
Commerce, however, disagreed with the evaluation that its cost estimate was not reliable, as it had conducted two independent cost analyses that satisfied the agency of the reliability.
GAO maintained that the Census Bureau needs to meet all four of its characteristics to have a dependable estimate.