How the IRS Selects Tax Returns for Audits

Receiving an audit notice from the Internal Revenue Service (IRS) is a common concern for business owners. However, understanding how the selection process works can demystify the experience and shift the focus from anxiety to proactive preparation.

Selection for an audit does not automatically imply that an error has been made; it simply means a tax return has been flagged for a closer look. Here is an overview of the primary methods used by the IRS to identify returns for examination.

1. The Computer Screening Process (DIF Scoring)

The most common method for audit selection involves a sophisticated algorithm known as the Discriminant Inventory Function (DIF) system.

• • The Scoring Mechanism – As returns are processed, the IRS computer system assigns each a “DIF score.” This number represents the statistical potential for a return to contain errors or unreported income.

• • The Basis of Comparison – The system compares a return against “norms” for similar returns, often categorized by profession, income level, and industry. A return that deviates significantly from these statistical norms, such as unusually high business deductions compared to total revenue, may trigger a higher DIF score and catch the attention of a human screener. 

2. Random Selection

A portion of returns is selected through the National Research Program for purely statistical purposes. This process is random and serves as a tool for the IRS to update its data on current tax compliance trends. In these instances, the selection is not triggered by a specific red flag, but rather by the need to maintain the integrity of the broader tax system.

3. Related Examinations

The IRS often conducts “related examinations” when a return involves transactions with other entities or individuals. For example, if a business partner or an investor is under audit, the IRS may review the tax returns of associated parties to verify the consistency of shared financial data or reported transactions.

4. Information Matching Discrepancies

The IRS receives copies of various information returns, such as Forms 1099, W-2, and 1098. The system automatically compares the income and deductions reported on these forms against what is filed on a personal or business tax return. Discrepancies—such as missing income that was reported by a third party—are among the most frequent triggers for a correspondence (mail) audit.

5. Manual Review

When a computer algorithm or an information match identifies a return for potential examination, it does not immediately result in an audit notice. Instead, the return undergoes a manual review by experienced IRS personnel. These individuals determine whether the anomalies warrant further investigation or if the return should be accepted as filed.

The Importance of Documentation

The most effective defense against audit uncertainty is thorough documentation. Maintaining an organized record of receipts, invoices, and business logs provides the necessary evidence to support every position taken on a tax return.

If a notice is received, the best course of action is to review the specific issues raised by the IRS and provide the requested documentation promptly. Professional representation is an option that can help ensure the process is handled accurately and efficiently.

Please reach out to the firm to ensure financial records are audit-ready and that tax filings are positioned to meet all reporting requirements.