How the IRS Audit Process Works: Triggers, Types, and What to Expect

The IRS Audits Less Than 0.4% of Individual Returns — But Certain Red Flags Raise That Number Dramatically

In 2023, the IRS audited approximately 582,000 individual income tax returns out of roughly 150 million filed — an overall audit rate of about 0.38%. But that average obscures enormous variation. Returns claiming the Earned Income Tax Credit face audit rates exceeding 1.5%. High-income filers reporting over $1 million in income face rates approaching 2–5%. Sole proprietors with large deductions relative to reported income also attract disproportionate scrutiny. Understanding how audits are selected, what they entail, and how to respond appropriately removes much of the fear that surrounds one of the IRS's most powerful enforcement tools.

How Returns Are Selected for Audit

The IRS uses several selection methods, often in combination:

• Discriminant Function System (DIF): A computer scoring system that compares deductions, credits, and income items against statistical norms for your income range. Returns that deviate significantly from expected patterns score higher and receive closer review.
• Related examinations: If your business partner, employer, or a charity you donated to is audited, your return may be pulled for review as well.
• Information document matching: The IRS receives copies of W-2s, 1099s, K-1s, and other forms. Returns where reported amounts don't match these documents are flagged automatically.
• Random selection: A small percentage of returns are chosen purely at random as part of the National Research Program, used to update DIF norms.

Types of IRS Audits

Correspondence audits are by far the most common — accounting for roughly 75% of all audits. They typically address a single issue, like an unreported 1099 or a questioned deduction, and can often be resolved by mailing supporting documentation within the requested timeframe.

Common Audit Red Flags

• Schedule C losses year after year: The IRS may reclassify a business as a hobby if it reports losses in 3 or more of the last 5 years, disallowing deductions
• Home office deductions: Particularly scrutinized; the space must be used regularly and exclusively for business
• Large charitable deductions: Especially noncash contributions; the IRS has specific thresholds above which appraisals are required
• Unreported income: Mismatches between reported income and information documents trigger automatic notices
• Round numbers throughout the return: Statistically unlikely and often suggests estimation rather than record-keeping
• High meals and entertainment deductions relative to revenue: A ratio significantly above industry norms draws attention

Your Rights During an Audit

The IRS Restructuring and Reform Act of 1998 enshrined taxpayer rights codified in the Taxpayer Bill of Rights. During an audit, you have the right to:

• Representation — you can have a CPA, enrolled agent, or tax attorney represent you without being present yourself
• Know the specific issues under examination before providing documents
• Limit the scope to the items in the audit notice — auditors cannot expand into other years or issues without justification
• Appeal any adverse findings within the IRS before going to court
• Privacy — information gathered during the audit cannot be used outside the examination without consent or court order

The Audit Process: What Happens Step by Step

What Happens If the Audit Finds an Error

If the IRS determines additional tax is owed, it calculates the deficiency plus applicable interest (currently around 8% per year) and potentially penalties. Common penalties include:

• Accuracy-related penalty: 20% of the underpayment if due to negligence or substantial understatement
• Civil fraud penalty: 75% of the underpayment if the IRS determines intentional fraud
• Failure-to-file and failure-to-pay penalties: Separate from audit penalties, but can compound the total amount owed

Penalties can often be abated for first-time offenders through the IRS's First Time Abate program, which waives certain penalties for taxpayers with a clean compliance history for the prior three years.

This article is for informational purposes only and does not constitute financial advice.