Lucas Goodman (Office of Tax Analysis, U.S. Treasury Department) & Andrew Whitten (Office of Tax Analysis, U.S. Treasury Department; Google Scholar) present Automating the 1040: How Accurately and for Whom Can We Prepopulate Individual Income Tax Returns? at Georgetown today as part of its Tax Law and Public Finance Workshop hosted by Brian Galle:

To make tax filing more efficient and to redistribute the filing burden, some commentators have proposed having the IRS pre-populate tax returns for individuals. We evaluate this hypothetical policy using a large, nationally representative sample of returns filed for tax year 2019. Between 40 and 50 percent of returns could be accurately pre-populated using information returns and the prior year return. 

Accuracy rates decline with income and are higher for taxpayers who have fewer dependents or are unmarried. We also examine a random sample of 2019 non-filers and estimate that pre-populated returns would indicate $7.1 billion in refunds due to 9 million (24%) of them.