Performance problems with the Census Bureau's IT system caused delays in collecting and processing questionnaires for the 2010 census, according to a government watchdog agency.

The Census Bureau's nonresponse follow-up (NFRU) was hampered by glitches in data collection that led to processing backlogs, according to a report by the Government Accountability Office (GAO) published this week.

The GAO found that the bureau completed NFRU under budget, spending $1.59 billion on the process, which was about $660 million less than what the bureau had originally estimated. However, census costs overall have been doubling on average every decade since 1970. The 2010 census cost about $13 billion, while the 2020 census is expected to cost as much as $30 billion, according to the GAO.

The watchdog agency said the Census Bureau should fix problems with its IT system to improve the process and avoid unnecessary expenditures for the next census, which will occur in 2020.

Specifically, a program for using handheld computers to collect information for NRFU and address canvassing "experienced substantial schedule delays and cost increases," according to the report, so much so that it was abandoned in favor of the traditional paper questionnaires.

Even that didn't ensure that the process ran smoothly, the GAO said. The system the bureau used to manage the field operation in lieu of the handheld system, Paper Based Online Computer System (PBOCS), also didn't work properly, buckling under the load of data it had to process, according to the report.

Despite working "aggressively" to improve the performance of PBOCS by upgrading hardware and software before the NRFU process, the system experienced outages, slow performance, and problems generating and maintaining timely progress reports.