The U.S. Government Accountability Office is offering recommendations to close the tax gap, a move it says could yield large fiscal benefits even if there is only a modest narrowing of the gap between what is paid and what is owed.

In a “snapshot” report issued February 27, 2023, the GAO cited Internal Revenue Service-reported figures for the years 2014-2016 that show taxpayers owed $3.3 trillion in taxes but paid only $2.8 trillion. GAO analysis of IRS data attributes the gap to three key factors: underreporting ($398 billion); underpayment ($59 billion); and nonfiling ($39 billion).

GAO reported a number of factors that have contributed to the tax gap, including limited third-party information reporting, declines in audit rates, worsening customer service and the complexities of the tax code. It also noted that abusive tax shelters also play a role in contributing to the tax gap. The report did not quantify how much these factors contributed to the tax gap.

“Our work shows there are no easy ways to reduce the taxgap,” the report states. “Multiple approaches are needed to address the many causes of tax noncompliance.”

The government watchdog recommends that the IRS re-establish quantitative goals to reduce the tax gap; expand third-party information reporting; digitize taxpayer returns to make them more readily available to enforcement programs; and make it easier for individuals to report preparers and promoters involved in abusive tax schemes.

It also is recommending that Congress give the IRS explicit authority to establish professional requirements for paid preparers; expand third-party reporting requirements related to real estate; expand IRS authority to correct errors and discrepancies between taxpayer reported and other government collected information; and requiring paper returns include a scannable code to allow information to be processed digitally.

The GAO did not quantify how much benefit the federal government could get with even a modest reduction in the tax gap.