If you have just received an IRS audit notice, the first question is almost always the same: why me? Did the IRS catch something specific? Did a software algorithm flag the return? Did someone report you? Was it random?

The honest answer is that IRS audit selection is rarely random, and “why was I selected for an IRS audit” usually has a specific, identifiable answer. The IRS receives more than 150 million individual returns each year and can examine only a small fraction of them.

By the time a return is selected for audit, it has typically survived multiple layers of screening, and the selection signals something specific about the return, the taxpayer, or the context.

This article walks through the main paths returns take to audit, explains what each path signals about the IRS’s interest in the case, and provides a practical overview of what happens after a return is selected.

The perspective is informed by Kugelman Law attorney Otto Bosch, who served as a Revenue Agent in the IRS Global High Wealth Group within the Large Business and International (LB&I) Division before joining the firm in February 2026.

The Basic Reality of IRS Audit Selection

Audit selection is a triage. The IRS uses a combination of statistical models, information matching systems, project initiatives, and human judgment to identify the returns most likely to produce meaningful adjustments. Every return that reaches a Revenue Agent’s desk has passed through that triage, which means by the time the examination opens, the IRS has already decided the return is worth investing real resources in.

The corollary matters. Selection is not random, but it also does not mean the IRS has already concluded that the return is wrong. It means the IRS believes there is enough probability of a meaningful adjustment to justify the cost of the audit. The defense’s job is to test that probability in order to show that the issues the IRS expected to find either do not exist or have a defensible explanation.

The Main Paths Returns Take to Audit

Returns reach audit through several distinct mechanisms. The path tells the defense team something about how the case will likely develop.

DIF Scoring (Discriminant Function System)

The Discriminant Function (DIF) system is the IRS’s statistical model for scoring returns based on the likelihood that an examination would produce an adjustment. Every individual return is assigned a DIF score. High-DIF returns are routed for review and potential selection.

The specific factors the DIF model weights are not public, but the model is built on historical audit results — meaning returns with characteristics similar to returns that have produced adjustments in the past will score higher. Returns with characteristics that historically correlate with clean audits will score lower. Most ordinary individual audits begin as DIF-selected cases.

Information Matching

The IRS receives extensive third-party information returns — W-2s, 1099s, K-1s, broker statements, Forms 5498, foreign account reports under FATCA, cryptocurrency exchange data, mortgage interest statements, and many others. These information returns are matched against the corresponding amounts on filed returns.

Where the data matches, no audit. Where the data does not match — a 1099 the IRS received that is not reported on the return, a K-1 missing from the return entirely, a broker statement showing dispositions not reflected in Schedule D — the mismatch generates a notice. Small mismatches typically produce a CP2000 notice that resolves through correspondence. Material mismatches can escalate into a full examination.

Related-Return Pickups

When the IRS is examining one return and identifies issues that connect to another taxpayer’s return, the related return can be opened for examination as well. A partnership audit triggers examinations of the partners. A corporation audit can trigger shareholder examinations. Family-owned business structures can produce coordinated audits across multiple related taxpayers.

Related-return pickups are one reason a single audit can quickly grow. They are also one reason that examinations involving high-net-worth families, private equity structures, and other multi-entity arrangements tend to expand once the IRS begins looking at one piece of the structure.

Compliance Projects and Initiatives

The IRS regularly announces or quietly runs enforcement initiatives focused on specific issues — syndicated conservation easements, microcaptive insurance arrangements, deferred legal fee structures, cryptocurrency reporting, foreign account compliance, employee retention credit claims, and others. Returns within the scope of an active initiative are far more likely to be selected.

Project-driven examinations look different from DIF-driven examinations. The agent has typically been trained specifically on the project’s target issue, has examined other taxpayers in the same project, and has internal guidance on what positions to develop. Recognizing a project-driven audit early is one of the most valuable defensive insights an examination can produce.

Whistleblower and Informant Referrals

The IRS Whistleblower Program pays awards for actionable information about tax noncompliance, and substantiated referrals can result in examination. Whistleblowers are sometimes disgruntled former employees, sometimes former spouses, sometimes business partners, sometimes professional informants who specialize in identifying patterns of noncompliance.

A whistleblower-initiated audit is structurally different from a DIF-selected audit. The IRS already has specific information about specific issues from someone with inside knowledge. The agent’s working hypothesis is more specific, and the IDR responses will be evaluated against information the IRS already has.

LB&I and Global High Wealth Selection

For the most complex high-net-worth and corporate examinations, returns are selected through specialized risk-based processes within the Large Business and International division. The Global High Wealth Group within LB&I uses an enterprise audit approach that considers the entire web of related entities, trusts, partnerships, and personal returns associated with a wealthy taxpayer as a coordinated whole.

Selection by LB&I or the Global High Wealth Group signals that the IRS has decided the case warrants its most experienced examination resources. These cases tend to involve longer timelines, multiple specialists, integrated analysis across many entities, and significant dollar exposure.

Random Selection (National Research Program)

The IRS periodically conducts the National Research Program (NRP), in which a statistically representative sample of returns is audited regardless of their DIF score. The NRP exists to calibrate the DIF model and to measure the tax gap. NRP audits feel random because, within their sample, they are — but the sample itself is small relative to the overall audit caseload.

How to Read Your Audit Notice for Selection Clues

The audit notice itself contains information that helps identify the selection path:

• The issuing office. Notices from IRS Service Centers usually indicate correspondence-level matters driven by information matching. Notices from field offices generally indicate more substantive examinations.
• The examiner’s title. A Tax Examiner suggests a correspondence audit. A Tax Compliance Officer suggests an office audit. A Revenue Agent suggests a field audit. Identification with LB&I or the Global High Wealth Group suggests a specialized examination.
• The issues identified. Where the notice identifies a specific issue (a missing 1099, an unsubstantiated deduction, a credit eligibility question), the selection was likely driven by that issue. Where the notice references broad areas of the return (Schedule C in its entirety, all foreign account activity, all cryptocurrency transactions), the selection was likely broader.
• The form referenced. CP2000 notices indicate information matching mismatches. Letter 566 typically initiates correspondence audits. Letter 2205 typically initiates field examinations.

For more on how the type of audit identified in your notice affects defense strategy, see our article on field audit vs. office audit vs. correspondence audit.

What the Selection Path Tells You About Your Audit

Reading the selection path is one of the first defensive moves in any audit. Different paths suggest different scope, different agent posture, and different defense priorities:

• DIF-selected audits tend to be focused on the specific issues that drove the score. Strong substantiation on those issues often produces a clean closing.
• Information-matching audits are data-driven and narrow. The defense’s job is typically to substantiate the reported position or to demonstrate why the third-party data is inaccurate.
• Related-return audits follow specific connecting issues. The defense should anticipate that the agent already has information from the related taxpayer’s return.
• Project-driven audits concentrate on the project’s target issue. The agent’s positions are likely well-developed; the defense’s job is to engage them on the specific facts of the case.
• Whistleblower audits assume the IRS has specific information from an insider. The defense should expect targeted questions and should not assume the agent is starting from neutral.
• LB&I and Global High Wealth audits are the most resource-intensive examinations the IRS conducts. The defense methodology needs to match the agency’s commitment to the case.

What Happens After Selection — The Audit Lifecycle

Once a return is selected and an examination opened, the audit unfolds along a fairly predictable arc:

Pre-contact analysis. Before any notice goes out, the agent reviews the return, prior-year filings, selection notes, and third-party data. A working hypothesis about the case is formed before the taxpayer hears anything.

Initial notice and opening conference. The taxpayer receives the audit notice. Depending on the audit type, an opening conference may be scheduled.

Information Document Requests (IDRs). The agent issues IDRs requesting documents and information. The first IDR is one of the most important documents in the entire audit — we discuss this in detail in our article on how to respond to an IRS IDR.

Issue development and fieldwork. The agent reviews documents, conducts interviews where appropriate, develops issues, and builds workpapers. This phase can last months — sometimes years — for complex examinations.

Closing. The audit closes in one of three ways: no change (the return is accepted as filed), agreed (the taxpayer accepts the proposed adjustments), or unagreed (the case proceeds to Appeals and potentially to U.S. Tax Court).

For a deeper walk-through of how the audit unfolds inside the IRS, see our pillar articles on what an IRS Revenue Agent does and inside the IRS audit playbook.

How Long Will Your Audit Take?

Audit duration varies dramatically by type and complexity:

• Correspondence audits typically resolve in a few months from the initial notice through final closing.
• Office audits typically resolve in three to six months, with the single in-person appointment as the central event.
• Field audits commonly take a year or more for substantive cases, and complex multi-year LB&I or Global High Wealth examinations can run two years or longer.

Several factors affect timing: the complexity of the issues, the responsiveness of the taxpayer and representative, whether specialists are brought in, whether the case proceeds to Appeals, and whether litigation ultimately follows. Faster is generally better for the taxpayer, but rushed responses produce worse outcomes than measured ones.

Common Misconceptions About IRS Audit Selection

Several beliefs about audit selection are common but inaccurate:

“It was random.” Almost never. With limited exceptions like the National Research Program, audit selection is driven by specific factors that flagged the return.

“I was unlucky.” Selection is not luck. It is the output of statistical models, data matching, project initiatives, and human judgment — each of which is calibrated to identify returns that warrant examination.

“The IRS is targeting me.” Very rarely. Targeting in the sense of personal animus is extremely uncommon in modern IRS practice. The selection systems are largely impersonal. What feels like targeting is almost always the output of a model or a project the taxpayer happens to fit.

“If I just amend my return, I can avoid the audit.” Sometimes — but the answer is fact-specific. Amending a return after an audit has been opened typically does not stop the audit, and amending in some scenarios (particularly where criminal exposure is possible) can create more problems than it solves. The decision should be made with counsel.

“Audits are inevitable once you reach a certain income.” High income increases audit probability, particularly for taxpayers reaching Global High Wealth thresholds. But the relationship is probabilistic, not deterministic, and many high-income taxpayers never face audits while many middle-income taxpayers do.

What You Should Do Right Now

If you have just received an audit notice, the right immediate steps are practical and measured:

1. Read the notice carefully. Identify the audit type, the issuing office, the named examiner, the issues raised, and the deadline.
2. Preserve relevant records. Do not destroy or alter any document referenced in the notice or potentially related to the issues raised. Document preservation obligations are serious.
3. Do not respond reflexively. The instinct to “explain things” quickly and put the matter behind you is almost always counterproductive. Unprepared communication with the IRS is one of the most common ways audits go badly.
4. Do not call the agent without preparation. Statements made during informal calls become part of the audit record.
5. Identify what kind of representation you need. For straightforward correspondence audits, your preparer may be sufficient. For substantive examinations, experienced controversy counsel is generally appropriate. We discuss the choice in our article on tax attorney vs CPA for IRS audit defense.
6. If any aspect of the case involves potential criminal exposure — significant unreported income, undisclosed foreign accounts, false statements to the IRS, or fabricated records — retain an attorney before any further communication with the IRS. See our article on eggshell audits explained for the underlying framework.

How Kugelman Law Approaches Selection Analysis

The first thing Kugelman Law does on a new audit matter is read the case before doing anything else. That means analyzing the selection path, identifying the likely scope of the examination, modeling the taxpayer’s exposure across the universe of issues the IRS may develop, and assessing whether any aspect of the case carries elevated risk.

Founder Alex Kugelman brings nearly two decades of federal tax controversy experience, including litigation in U.S. Tax Court and U.S. District Court. Otto Bosch brings the inside-the-IRS perspective from his time as a Revenue Agent in the LB&I Global High Wealth Group — including direct experience with the selection systems and divisional procedures that govern most substantive audits. We covered the strategic value of this combination in detail in our article on why a former IRS revenue agent attorney changes audit defense.

Representative outcomes from the firm’s audit defense practice include a $365,000 tax debt reduced to a zero-dollar liability, a multi-year audit and non-filing matter resolved with minimal payment, and ten years of unfiled returns brought into compliance with a successful outcome. Results depend on specific facts. Past results do not guarantee future outcomes.

Frequently Asked Questions

Does the IRS audit randomly?

Almost never. With limited exceptions like the National Research Program (which audits a small statistically representative sample to calibrate the DIF model), IRS audit selection is driven by specific factors — DIF scoring, information matching, related-return pickups, compliance projects, whistleblower referrals, and specialized division processes. Most audits are the output of identifiable selection paths.

What is a DIF score?

The Discriminant Function (DIF) score is a numerical rating the IRS assigns to each return based on the likelihood that an examination would produce a meaningful adjustment. High-DIF returns are routed for review and potential selection. The specific factors the model weights are not public, but the model is built on historical audit results — meaning returns with characteristics similar to returns that have produced adjustments in the past will score higher.

Can someone report me to the IRS for tax evasion?

Yes. The IRS Whistleblower Program accepts and acts on referrals about tax noncompliance, and the program pays awards in qualifying cases. Common whistleblowers include former employees, former spouses, business partners, and professional informants. Substantiated referrals can result in examinations that look different from DIF-selected audits because the agent has specific inside information from the outset.

Can I prevent future IRS audits?

No taxpayer can guarantee future audit-free status, but several factors reduce audit probability: complete and accurate reporting, clean substantiation, consistency across years, prompt compliance with information reporting obligations, and avoidance of audit-flag positions where alternatives exist. For taxpayers with prior compliance issues, a clean voluntary disclosure or corrected return — handled with experienced counsel — can sometimes resolve historical exposure and lower future audit risk.

How long does the IRS have to audit my return?

The standard statute of limitations on assessment is three years from the date the return was filed (or its due date, if later). It extends to six years for substantial omissions of gross income exceeding 25 percent. There is no statute of limitations for fraudulent returns or non-filed returns. For FBAR and other information return failures, separate limitations periods apply.

Speak With Kugelman Law

If you have received an IRS audit notice — or have reason to believe one is coming — schedule a paid privileged consultation with Kugelman Law. Call (415) 968-1780 or visit our contact page. All consultations are fully protected by attorney-client privilege.

About the Author

Alex Kugelman is the founder and managing attorney of Kugelman Law, a boutique tax controversy and cryptocurrency tax firm serving California and clients nationwide. With nearly two decades of federal tax controversy experience — including litigation in the U.S. Tax Court and U.S. District Court — Alex represents individuals and businesses in their most consequential disputes with the IRS and the California Franchise Tax Board. He is a member of the State Bar of California (No. 255463), admitted to the Bar of the U.S. Supreme Court, and served as San Francisco Chair of the Federal Bar Association’s Tax Division in 2018. He is also a member of the Marin County Assessment Appeals Board and a nationally recognized cryptocurrency tax attorney featured on the Bitcoin.tax podcast and The Mark Milton Show. Read Alex’s full bio.

Each type involves different procedures, different IRS personnel, different scope, and different stakes. Identifying which type of audit you are facing is the first defensive step in any examination.

This article walks through the three audit types from the inside — how they are conducted, who staffs them, what issues each tends to involve, and what each one signals about the IRS’s interest in the case.

The perspective is informed by Kugelman Law attorney Otto Bosch, who served as a Revenue Agent in the IRS Global High Wealth Group within the Large Business and International (LB&I) Division before joining the firm in February 2026. For broader background on how Revenue Agents operate, see our companion articles on what an IRS Revenue Agent does and inside the IRS audit playbook.

Why the Type of IRS Audit Matters

The type of audit determines almost everything else about the examination. Correspondence audits are conducted through the mail, generally by tax examiners working from IRS Service Centers, and typically focus on narrow, document-driven issues.

Office audits are conducted in person at IRS offices, generally by Tax Compliance Officers, and cover a broader scope.

Field audits are conducted at the taxpayer’s place of business or representative’s office, generally by Revenue Agents, and are the most substantive type — often involving multi-year examinations of complex returns.

The differences matter for three reasons:

Procedurally, the workflows, timelines, and document expectations differ significantly across types.

Substantively, the issues likely to arise differ based on the audit type. A correspondence audit is rarely the right vehicle for a complex partnership examination. A field audit is rarely opened for a missing 1099.

Strategically, the level and type of representation appropriate to each varies. A correspondence audit may be handled directly by the taxpayer or the preparer. A field audit conducted by an LB&I Revenue Agent almost always requires experienced controversy counsel.

Correspondence Audits

A correspondence audit is conducted entirely through written communication, typically initiated by a letter from the IRS — often a CP2000 notice or a similar document — that identifies a specific discrepancy and requests substantiation or explanation.

Who conducts them. Correspondence audits are generally handled by tax examiners at IRS Service Centers, working through the Automated Underreporter (AUR) program or similar automated functions. The taxpayer typically does not have a single named agent to communicate with. Replies go to a Service Center, where a different reviewer may process each response.

Typical issues. Correspondence audits focus on narrow, well-defined issues that can be resolved through document production:

• Information matching mismatches (a 1099 the IRS received but does not match the return)
• Missing or incorrect Social Security numbers for dependents
• Earned Income Tax Credit eligibility verification
• Education credit substantiation
• Itemized deduction verification on a single category (charitable contributions, medical expenses)
• Simple math errors or credit calculation questions

Scope. Limited and pre-defined. The IRS letter identifies what is being examined and (usually) limits the inquiry to that issue.

Risk profile. Correspondence audits are not low-stakes by default — many produce significant adjustments — but the risk of unbounded expansion is lower than with office or field audits. The greater risk is mishandling: failing to respond by the deadline, responding incompletely, or responding in a way that creates new issues.

When to engage counsel. Most correspondence audits do not require attorney involvement. They can typically be handled by the taxpayer directly or by the return preparer. Counsel is appropriate where the dollar amounts are significant, where the underlying facts touch on potential criminal exposure, or where the correspondence audit appears to be a precursor to a broader examination.

Office Audits

An office audit is conducted in person at an IRS office, typically as a single appointment lasting several hours to a full day. The taxpayer (or representative) brings requested documents to the appointment and meets with the examiner to address specific issues.

Who conducts them. Office audits are generally conducted by Tax Compliance Officers (TCOs), though Revenue Agents may handle some office examinations. Unlike correspondence audits, the taxpayer has a single named examiner with whom communications occur.

Typical issues. Office audits address moderately complex issues that benefit from in-person review:

• Schedule C examinations of self-employed taxpayers
• Schedule E rental property issues
• More complex itemized deduction questions (including travel and entertainment substantiation)
• Multi-year individual return issues
• Credit eligibility questions requiring document review

Scope. Broader than correspondence audits, narrower than field audits. The IRS will typically issue an Information Document Request before the appointment listing the specific documents and issues to be examined.

Risk profile. Office audits carry meaningful risk of expansion. Issues identified during the appointment can lead to follow-up examinations, related-return pickups, or escalation to a field audit if complexity warrants. Statements made during the appointment become part of the examination record.

When to engage counsel. Office audits frequently benefit from representation, particularly where the issues are substantive, the dollar amounts are meaningful, or the taxpayer is uncomfortable with the prospect of in-person examination by a trained IRS employee. CPAs and EAs can represent in office audits; attorneys add the privilege protection and litigation backstop that matter in more complex cases.

Field Audits

A field audit is the most comprehensive type of IRS examination. It is conducted in person at the taxpayer’s place of business, the representative’s office, or another location convenient to the examination, and typically extends over months — sometimes years — rather than days.

Who conducts them. Field audits are conducted by Revenue Agents. The division and specialization of the Revenue Agent reflects the type of case:

• Small Business / Self-Employed (SB/SE) Revenue Agents handle most individual and small-business field audits
• Large Business and International (LB&I) Revenue Agents handle complex corporate, partnership, and high-net-worth examinations
• The Global High Wealth Group within LB&I handles the most specialized examinations of the wealthiest U.S. taxpayers, using an enterprise audit approach that considers entire structures of related entities and transactions

Typical issues. Field audits address the most complex tax issues:

• Multi-year individual and business return examinations
• Partnership and S-corporation issues, including basis disputes and related-party transactions
• High-net-worth taxpayer examinations involving multiple entities and structures
• Cryptocurrency examinations of active traders, NFT participants, and DeFi users — covered in our article on inside an IRS cryptocurrency audit
• Foreign account and offshore disclosure matters
• Allegations of fraud or willful conduct
• Industry-specific examinations conducted as part of LB&I campaigns

Scope. Field audits typically cover one or more complete tax years, with the agent reviewing the return in its entirety rather than focusing on a single issue. Multiple Information Document Requests are issued over the course of the examination, with the scope evolving as issues develop.

Risk profile. Field audits represent the IRS’s most resource-intensive examination type. By the time the IRS opens a field audit, the agency has decided the case is worth investing significant time and analytical resources in. Cases conducted under the Global High Wealth Group’s enterprise approach use multiple specialists and consider the full web of related entities and transactions.

When to engage counsel. Field audits — particularly those conducted by LB&I or the Global High Wealth Group — almost always benefit from experienced tax controversy counsel. The combination of substantive complexity, multi-year scope, specialized examiner training, and significant dollar exposure makes attorney representation the appropriate default. Where there is any potential for criminal exposure or aggressive penalty positions, attorney representation is essential. We covered this calculus in detail in our article on tax attorney vs CPA for IRS audit defense.

Where the Three Types Overlap and Where They Don’t

A few important nuances apply across all three audit types:

The taxpayer’s legal rights are the same in each type. The right to representation, the right to obtain a copy of the audit report, the right to appeal proposed adjustments, the right to challenge a notice of deficiency in U.S. Tax Court — these rights do not vary based on whether the audit is conducted by correspondence, in an office, or in the field.

The substantiation rules are the same. Section 274(d) substantiation requirements for travel and entertainment expenses, basis documentation requirements, charitable contribution substantiation under Section 170 — these requirements apply identically across audit types. The differences are in how and how rigorously they are tested.

Audits can convert from one type to another. A correspondence audit that uncovers complexity can be escalated to an office or field audit. An office audit that surfaces issues outside the original scope can become a field audit. A field audit that develops potential criminal exposure can be referred to IRS Criminal Investigation. Recognizing the signals that an audit is converting type is one of the most valuable defensive insights — and it is precisely the kind of inside-the-IRS perspective that comes from prior IRS service.

How the Type of Audit Shapes Defense Strategy

Defense strategy in any IRS examination begins with correctly identifying the type of audit, the IRS division conducting it, and the specific examiner’s training and authority. From there, several principles apply:

For correspondence audits, the defense priority is responsiveness and accurate document production. Missing the deadline, providing incomplete responses, or volunteering information not requested are the most common errors. Where the issue can be cleanly substantiated, a focused response often produces a no-change closing.

For office audits, the defense priority is preparation. The single in-person appointment is where the audit’s record is largely built. Pre-appointment review of documents, anticipation of likely questions, and preparation of organized exhibits typically determine the outcome. As discussed in our article on how to respond to an IRS IDR, the appointment is not the time for improvisation.

For field audits, the defense priority is methodology. Multi-year, multi-issue examinations require sustained, organized, document-driven defense across months or years. The record built during the field audit is the record that follows the case to Appeals, to U.S. Tax Court, and through any subsequent litigation. This is the type of audit where the inside-the-IRS perspective of a former Revenue Agent — the focus of our article on why a former IRS revenue agent attorney changes audit defense — most directly changes outcomes.

What Each Type Tells You About the IRS’s Interest in the Case

The type of audit the IRS opens carries information about the agency’s view of the case. A correspondence audit signals that the IRS has identified a specific, narrow issue and believes it can be resolved through document production. An office audit signals that the IRS sees enough complexity to warrant in-person review but not enough to justify field resources. A field audit — particularly one conducted by LB&I or the Global High Wealth Group — signals that the IRS believes the case is worth investing significant resources in.

Conversely, the absence of certain audit types can also be informative. A taxpayer whose return contains issues that would normally warrant a field audit, but who receives only a correspondence audit, may be facing a case where the IRS does not yet appreciate the scope. That dynamic creates specific defensive considerations — and is one of the reasons experienced controversy counsel reads each audit’s type, scope, and selection signals carefully before deciding how to respond.

How Kugelman Law Handles Each Audit Type

Kugelman Law’s audit defense practice is calibrated to the type of audit and the complexity of the underlying issues. For correspondence audits with significant exposure or potential complexity, the firm provides focused review and response strategy. For office audits, the firm provides full pre-appointment preparation, representation at the examination, and follow-through. For field audits — particularly those conducted by LB&I or the Global High Wealth Group — the firm provides the sustained, methodology-driven defense that complex multi-year examinations require.

Founder Alex Kugelman brings nearly two decades of federal tax controversy experience, including litigation in U.S. Tax Court and U.S. District Court. Otto Bosch brings the inside-the-IRS perspective from his time as a Revenue Agent in the IRS Global High Wealth Group within LB&I — including direct experience with the examination types and divisional procedures that govern most substantive audits.

Representative outcomes from the firm’s audit defense practice include a $365,000 tax debt reduced to a zero-dollar liability, a multi-year audit and non-filing matter resolved with minimal payment, and ten years of unfiled returns brought into compliance with a successful outcome. Results depend on specific facts. Past results do not guarantee future outcomes.

Frequently Asked Questions

How do I know what type of IRS audit I am facing?

The initial IRS letter identifies the type of audit. A letter asking for documents to be mailed in is a correspondence audit. A letter scheduling an in-person appointment at an IRS office is an office audit. A letter from a Revenue Agent proposing to meet at your place of business or your representative’s office is a field audit. The letter will also identify the examiner’s title (tax examiner, Tax Compliance Officer, Revenue Agent) and the IRS division conducting the examination.

Is a correspondence audit less serious than a field audit?

Generally yes — but not always. Correspondence audits typically involve narrower issues and smaller dollar amounts, but they can produce significant adjustments and can escalate to broader examinations if the response surfaces complexity. The right approach is to take any IRS audit seriously regardless of type.

Can an office audit turn into a field audit?

Yes. Where the issues identified during an office audit prove more complex than expected, or where the scope expands to multiple years or related entities, the IRS can escalate the examination to a field audit. This is one of the reasons preparation for an office audit appointment matters — what surfaces at the appointment shapes whether the case stays narrow or expands.

Do I have to let an IRS Revenue Agent into my home or business?

You generally have the right to conduct an audit at your representative’s office rather than at your home or place of business, particularly when you are represented by an attorney, CPA, or EA. Revenue Agents typically accommodate reasonable location requests where the relevant records can be made available.

Who decides what type of audit will be conducted?

The IRS decides, based on the issues identified at selection, the complexity of the return, and the dollar amounts at stake. Taxpayers generally do not have the ability to elect one type over another, though the choice of representative and the location of the audit can be negotiated in field examinations.

Speak With Kugelman Law

If you have received an IRS audit notice of any type — correspondence, office, or field — schedule a paid privileged consultation with Kugelman Law. Call (415) 968-1780 or visit our contact page. All consultations are fully protected by attorney-client privilege.

About the Author

Alex Kugelman is the founder and managing attorney of Kugelman Law, a boutique tax controversy and cryptocurrency tax firm serving California and clients nationwide. With nearly two decades of federal tax controversy experience — including litigation in the U.S. Tax Court and U.S. District Court — Alex represents individuals and businesses in their most consequential disputes with the IRS and the California Franchise Tax Board. He is a member of the State Bar of California (No. 255463), admitted to the Bar of the U.S. Supreme Court, and served as San Francisco Chair of the Federal Bar Association’s Tax Division in 2018. He is also a member of the Marin County Assessment Appeals Board and a nationally recognized cryptocurrency tax attorney featured on the Bitcoin.tax podcast and The Mark Milton Show. Read Alex’s full bio.

If you understand what an IRS Revenue Agent does on paper, you understand half of an examination. The other half — the half that determines outcomes — is how they think. The mental model an agent brings to a case shapes which issues get developed, which positions get pushed, which compromises get accepted, and ultimately whether your audit closes for $0, for the full proposed adjustment, or somewhere in between.

This is the IRS audit playbook from inside. Not the procedural manual published in the Internal Revenue Manual — that document is publicly available — but the working mental framework that experienced Revenue Agents actually use as they prioritize cases, identify issues, and make the dozens of small decisions that aggregate into an examination’s outcome.

This article is informed by Kugelman Law attorney Otto Bosch, who served as a Revenue Agent in the IRS Global High Wealth Group within the Large Business and International (LB&I) Division before joining the firm in February 2026. For an introduction to what Revenue Agents formally do and how examinations are structured, see our companion piece on what an IRS Revenue Agent does. The article below picks up where that one leaves off — focused not on the structure of an audit but on the thinking behind it.

How Returns Get on the Radar in the First Place

Most taxpayers imagine return selection as a uniform process. In practice, it is a triage. The IRS receives more than 150 million individual returns each year, and the examination function can pursue only a small fraction of them. Every return that reaches a Revenue Agent’s desk has survived multiple rounds of selection — which means by the time the examination opens, someone in the IRS has already decided this return is worth investing real resources in.

That triage happens through several mechanisms — DIF scoring, related-return pickups, information matching, project initiatives, and others — which we covered in detail in our prior article. What matters for understanding the playbook is the agent’s mindset when a case is assigned: the agent assumes there is something to find. The selection process is statistical, not certain — but it is good enough that experienced agents do not approach examinations as fishing expeditions. They approach them as recovery operations: the system has flagged something, and the agent’s job is to figure out what.

This default assumption matters defensively. Many taxpayer responses during an audit are calibrated to “look cooperative” or “explain things,” on the assumption that the agent is starting from neutral. The agent is not starting from neutral. The agent is starting from “the system thinks something is here.” Responses calibrated to that posture are different from responses calibrated to a neutral counterparty.

How a Revenue Agent Builds a Case from Suspicion to Adjustment

An audit, viewed from the agent’s seat, is not a single inquiry. It is a layered case-building exercise. Each layer corresponds to a different mental task.

Stage 1: Pre-Contact Intuition

Before the agent ever issues a notice, they have read the return, the notes from selection, prior-year filings, and any third-party data already in IRS systems. They have formed a working hypothesis about what the case is — and a working list of issues they expect to develop. Experienced agents are usually right about the rough shape of the case before the first IDR ever leaves their desk.

What the taxpayer sees as the “first contact” is, from the agent’s perspective, the third or fourth phase of the case. Defense strategies that treat the opening conference as the start of the audit are already a step behind.

Stage 2: Issue Identification Through Documents

The first Information Document Request (IDR) is the agent’s tool for confirming or refuting the pre-contact hypothesis. They are not asking for documents because they want to read receipts. They are asking because they want to see whether reality matches their hypothesis — and where reality does not match, they want to see where the gaps are.

Experienced agents read taxpayer responses for three signals: what was produced, what was conspicuously absent, and what the production reveals about how the taxpayer keeps records. A neat, well-organized response signals a sophisticated taxpayer (and probably a careful preparer). A messy, partial, or contradictory response signals issues that are likely to multiply as the audit goes deeper. Both responses tell the agent how aggressively to invest in the case.

Stage 3: Position Development

Once issues are identified, the agent shifts from finding things to building something. A “position” is the IRS’s articulated theory for why a particular adjustment should be made — and the case file the agent builds to support that position is what survives into Appeals, into Tax Court, and into any settlement discussion.

This is where mental discipline starts to differentiate experienced agents from inexperienced ones. Strong positions are built on documents, third-party records, and clean factual narratives. Weak positions rely on inference, taxpayer statements, or agent-developed math that the taxpayer can re-do. A good defense team can usually tell within the first few exchanges which kind of position the agent is building.

Stage 4: Workpaper Construction and Supervisory Sign-Off

Workpapers are not the agent’s notes. They are the IRS’s case file — the formal record that managers, IRS Counsel, Appeals officers, and (if it gets that far) the Tax Court will rely on. Every position the agent develops must eventually be expressed in workpapers that withstand internal review.

This creates a meaningful internal filter. Positions an agent personally believes in but cannot reduce to a clean workpaper get dropped. Positions a manager pushes back on get refined or abandoned. Positions IRS Counsel will not support get withdrawn. The defense team that understands this filter — that knows which positions are likely to survive review and which are not — can apply pressure exactly where it is most likely to produce results.

The Internal Pressures That Shape Every Audit Decision

A Revenue Agent does not have unlimited time, and the IRS does not have unlimited capacity. Every audit operates under three quiet but constant pressures that shape decisions taxpayers rarely see.

Cycle time. Agents have caseload expectations. An audit that drags is an audit that pulls the agent away from their other cases — and from their performance metrics. This is one of the reasons that responsive, well-organized taxpayer cooperation often produces better outcomes than passive resistance: the agent’s incentive is to close the case efficiently, and giving them a clean path to closure is sometimes worth more than fighting every issue.

Review risk. Every aggressive position the agent advances will be reviewed — by the manager, by IRS Counsel, sometimes by Appeals. An agent who advances positions that get overturned at review damages their internal credibility. This is why agents are often reluctant to push aggressive penalty positions, civil fraud allegations, or controversial legal theories unless the workpapers genuinely support them. Recognizing the threshold at which an agent will or will not commit to a position is one of the highest-leverage insights a defense team can have.

Specialty referrals. Complex examinations frequently involve specialists — international examiners, computer audit specialists, financial product specialists, valuation engineers. Bringing in a specialist takes time and case management. Agents weigh the value of escalation against its cost. A defense that signals a serious specialist would face credible counter-arguments may shift the case toward narrower issues that the agent can resolve without bringing in additional resources.

What Agents Look For That Taxpayers Don’t Recognize

Some of the most valuable inside-the-IRS knowledge is also the most counterintuitive. The signals below are things Revenue Agents are trained to read but that taxpayers and unprepared representatives often miss entirely.

• Lifestyle versus reported income. Significant gaps between what the return shows and what the taxpayer’s life suggests — homes, cars, travel, business interests visible on social media — are flags agents notice early. The IRS has access to public records and increasingly to other data streams that make these comparisons routine.
• Round numbers. Returns full of round numbers (exactly $5,000 in expenses, exactly $10,000 in donations) signal estimation rather than documentation. Agents notice this and adjust the audit accordingly.
• Inconsistencies across years. A line item that appeared in 2022 but vanished in 2023 — or a deduction that scaled non-linearly with income — invites questions. Agents do not always pursue these, but they note them, and they shape the case file.
• Related-party transactions without arms-length characteristics. Loans between entities with no documented terms, payments to family members for unspecified services, or rent to controlled entities at non-market rates draw immediate attention.
• Cash-intensive businesses with thin paper trails. Restaurants, salons, contractor businesses, and other cash-heavy operations get scrutinized differently. Agents are trained to test reported gross receipts against industry norms and against bank deposits.
• Crypto and digital asset patterns. Returns showing digital asset activity without corresponding income items, or returns answering “no” to the digital asset question while exchange data shows otherwise, are flagged. Our article on IRS cryptocurrency audits explores this pattern in detail.
• Suspiciously timed amendments and late filings. Returns amended after the IRS opened an audit, or returns filed unusually late after notices, draw heightened attention. Agents note timing.

The pattern in all of these: agents are reading the return for signals about the taxpayer, not just about the numbers. Defense strategies that focus only on document production miss this dimension entirely.

How Agents Decide Whether to Push or Fold on an Issue

One of the most useful insights from inside the IRS is the recognition that agents do not push every issue to its limit. Many issues are noticed, considered, and quietly dropped — because the cost-benefit math does not work for the IRS.

The internal calculus on a given issue weighs:

• The dollar amount at stake
• The strength of the documentary support
• The likelihood the position survives Appeals or Tax Court
• The agent’s confidence in the legal theory
• The amount of additional development needed
• Whether the issue connects to other issues already being developed

Issues with strong documentary support, clear law, and meaningful dollars tend to be pushed. Issues with weak documentary support, ambiguous law, or trivial dollars tend to be dropped — even if the agent personally suspects the taxpayer’s position is wrong. The IRS does not pursue every theoretical adjustment. It pursues the ones that pencil out.

A sophisticated defense uses this. By making strong positions stronger and exposing weak positions early, the defense can shift the agent’s calculus on a case. Issues that were borderline tend to fall toward dropping. Issues that were marginal tend to settle on terms favorable to the taxpayer.

When the Audit Plays By Different Rules

Most of the playbook described above applies to standard examinations. There are categories of audits where the rules shift, and recognizing the shift is critical.

Eggshell audits — civil examinations with potential criminal implications — operate under an entirely different set of rules. The agent’s job is no longer to develop adjustments efficiently but to develop the record carefully, with an eye toward potential referral to IRS Criminal Investigation. Cooperation strategies that make sense in a routine audit can be catastrophic in an eggshell audit.

Global High Wealth and LB&I enterprise audits are also their own world. Cycle-time pressures are different, specialist resources are abundant, and the audit considers the entire web of related entities and transactions rather than the individual return. The mental model a Global High Wealth team brings to a case is integrated and patient in ways most taxpayers do not expect.

Project-driven examinations — audits opened as part of a focused enforcement initiative — also play differently. The agent has trained on the project’s target issue, has examined other taxpayers in the same project, and has internal guidance on what positions to develop. A defense that does not recognize the project’s contours will misread the agent’s posture entirely.

In each of these scenarios, defending without inside-the-IRS perspective is defending blind.

What This Means for Defense Strategy

The aggregate of everything above has a single practical implication for taxpayers under audit: the most consequential decisions in your audit are not the visible ones. They are the unseen ones — the agent’s pre-contact hypothesis, the position-building decisions in the workpaper file, the internal review pressures, the issue-by-issue cost-benefit calculations, and the specific signals the agent is reading from your responses that you do not realize you are sending.

This is what an IRS-insider perspective on the defense team actually changes. With Otto Bosch’s experience inside the IRS Global High Wealth Group and Alex Kugelman‘s nearly two decades of federal tax controversy litigation, Kugelman Law approaches every audit defense matter with a working understanding of the playbook on the other side of the table — and a credible litigation backstop if the case cannot be resolved administratively. We covered the full team capability in our article on why a former IRS revenue agent attorney changes audit defense.

Representative outcomes from the firm’s audit defense practice include a $365,000 tax debt reduced to a zero-dollar liability, a multi-year audit and non-filing matter resolved with minimal payment, and ten years of unfiled returns brought into compliance with a successful outcome. Results depend on specific facts. Past results do not guarantee future outcomes.

If you would like to discuss your IRS or FTB matter and how the firm’s combination of inside-the-IRS perspective and federal tax litigation experience can shape your defense, see our tax help resources or contact the firm directly.

Frequently Asked Questions

How do IRS auditors decide which issues to focus on?

Revenue Agents prioritize issues based on a combination of dollar magnitude, strength of documentary support, clarity of the legal theory, and the cost in agent time required to develop the position. Issues that are well-supported, technically clean, and material to the case tend to be pushed. Issues that are weak, ambiguous, or trivial tend to be quietly dropped — even when the agent personally suspects the taxpayer’s position is incorrect.

What red flags do IRS auditors look for?

Common signals include lifestyle inconsistent with reported income, returns full of round numbers, year-over-year inconsistencies in reported items, related-party transactions without arms-length characteristics, cash-intensive businesses with thin documentation, digital asset activity that does not align with reported income, and suspiciously timed amended or late-filed returns.

Can an IRS auditor decide to drop an issue mid-audit?

Yes. Issues that look promising in pre-contact analysis frequently get dropped during fieldwork as documents and explanations come in. Conversely, issues that were not initially identified can emerge from the development process. Audit scope is not fixed at the opening conference — it evolves as the case develops.

What does it mean when an IRS audit closes “no change”?

A no-change closing means the agent did not develop adjustments and the return is accepted as filed. This outcome is more common than many taxpayers assume. It occurs when the issues identified at selection do not survive document review, when the taxpayer’s documentation is strong, or when the cost-benefit math on the available positions does not justify pursuing them.

How do I know if my IRS audit is becoming an eggshell audit?

There are signals — agent questions that focus on knowledge, intent, and willfulness rather than documentation; involvement of specialized fraud or referral-related personnel; specific timing patterns in document requests; and sudden agent reluctance to discuss the case. Recognizing these signals reliably requires controversy experience. If you have any reason to suspect criminal exposure, attorney representation is essential and should be retained before any further communication with the IRS.

Speak With Kugelman Law

If you are facing an IRS audit, controversy, or complex federal tax matter — or if you suspect the IRS is preparing to open one — schedule a paid privileged consultation with Kugelman Law. Call (415) 968-1780 or visit our contact page. All consultations are fully protected by attorney-client privilege.