A project meant to be a decade in preparation, the 2020 census, still faces a number of uncertainties, which experts warn could lead to an inaccurate count with potentially large impacts on federal spending and congressional maps.

Though a pending Supreme Court decision over a citizenship question has dominated much of the conversation surrounding the census, other hurdles include the Census Bureau’s overall funding, cybersecurity concerns and untested methods.

“A really good way to screw up the American economy and waste a lot of taxpayer money is to have a bad census,” said Andrew Reamer, a George Washington University professor who studies census data.

Census data influences the flow of billions of federal dollars and thousands of business decisions, Reamer said, ranging from population surveys to assessments of market penetration.

The 2020 census is not the first to face last-minute challenges. Before the 2000 census, for instance, the Supreme Court banned the planned use of statistical sampling. Problems with handheld electronics during the 2010 census required the bureau to reintroduce paper enumeration.