Not all IRS audits are created equal. The type of audit you're facing — correspondence, office, or field — determines the scope of the examination, the level of documentation the IRS will demand, the timeline you're working against, and the stakes if the audit goes poorly. Most taxpayers who receive audit notices are facing a correspondence audit: a relatively contained examination conducted entirely by mail, focused on one or two specific items on the return. But for high-income individuals and business owners, the risk of an office or field audit — a far more comprehensive examination conducted in person by a trained revenue agent — is substantially higher. Understanding the differences between audit types from the moment you receive a notice is essential because the response strategy, the level of representation needed, and the potential exposure differ dramatically. This guide explains every audit type, the response strategy for each, and what factors determine which type of audit you're likely facing. IRS audit defense Key Takeaways Correspondence audits are conducted by mail and focus on 1–2 specific items — the most common and least severe audit type. Office audits involve an in-person meeting at an IRS office and cover a broader range of return items. Field audits are the most comprehensive — conducted at your business or representative's office — and carry the highest stakes. High-net-worth taxpayers face a fourth type: Global High Wealth (GHW) team audits covering all related entities. Your response strategy must match the audit type — over-responding to a correspondence audit can escalate it unnecessarily. What Is a Correspondence Audit and How Common Is It? A correspondence audit (also called a mail audit or 'corr audit') is conducted entirely through written communication between the IRS and the taxpayer. You receive an IRS letter — typically a CP2000,...