How big is the tax gap?

The “tax gap” is the difference between the amount of tax owed for a tax year and the amount that’s actually paid on time and voluntarily. How big is it? The Treasury Inspector General for Tax Administration (TIGTA) conducted an audit “to assess the IRS’s process for developing the tax gap estimates.” TIGTA found issues with how the IRS estimates the gap, often relying on “its staff’s experience” instead of “documented policies or procedures.” Also, certain sources of noncompliance, such as income from foreign activities and digital assets, aren’t part of the estimates. These issues raise questions about the quality and timeliness of the figures. Here’s the audit: https://bit.ly/3GDhP3e