A workers’ compensation premium audit reconciles the payroll your policy estimated at the start of the term against what you actually paid. If actual payroll came in higher, you owe the difference; if lower, you may get a credit. The audit is not an attack, it is the policy catching up to reality. The employers who get surprised are the ones who were not ready. The ones who prepared their payroll, class codes, owner records, and subcontractor certificates walk through it quickly. This guide is how to be the second kind.
The short version
- The audit reconciles estimated payroll to actual payroll for the term.
- The two biggest surprise charges come from class codes and uninsured subcontractors.
- Preparation before the audit prevents most disputes after it.
- Not every charge is an error. Read the audit against your own records before you push back.
Why the policy is audited
Every workers’ compensation policy is priced on estimated payroll, because no one knows in advance exactly what you will pay your people over the year. The audit closes that gap. It is routine, it happens on essentially every policy, and it is the reason your final premium can differ from what you were quoted. Understanding that up front reframes the audit from a threat into a reconciliation you can prepare for.
The record checklist
Get these together before the audit, and most of the friction disappears:
- Payroll registers and quarterly payroll reports.
- Job and duty descriptions for each role.
- Owner and officer records, including ownership percentages.
- Subcontractor payments, with a certificate of insurance for each sub.
- Any general ledger or disbursement records the auditor requests.
- State-by-state payroll if you operate in more than one state.
- Prior policy, endorsements, and last year’s audit.
- Any correspondence or worksheets from the current audit.
Reconcile the payroll
Payroll is the heart of the audit. Make sure it is separated correctly: overtime is usually reported at straight-time in many classifications, certain payments may be excludable, and payroll assigned to the wrong class code is the single most common source of an overcharge or a back charge. Line your reported payroll up against your actual registers before the auditor does.
Review the class codes and duties
An auditor assigns payroll to classifications based on the work performed, not the job title. If a field crew was reported partly as clerical, or a role was coded to a lower-rated class than the work supports, the audit will correct it, sometimes in your favor and sometimes not. Having clear duty descriptions ready lets you show the work accurately rather than argue about it later.
Owners, officers, and subcontractors
Two areas quietly drive audit surprises. First, owner and officer treatment: whether an owner is included or excluded, and at what payroll basis, affects the audit, so have the ownership and election records ready. Second, subcontractors: if a sub cannot show its own coverage for the work, its payments can be charged to you as payroll. The defense is simple and has to happen in advance, collect a certificate of insurance from every subcontractor before work begins. Our guide on subcontractors and workers’ comp goes deeper on that exposure.
Multiple locations and states
If your people work in more than one state, payroll has to be allocated correctly, and an Oregon policy does not automatically satisfy another state’s requirements. Washington in particular is monopolistic, so Washington work runs through Washington’s State Fund, not your Oregon policy. Get the state-by-state payroll right before the audit, because untangling it afterward is harder.
How to read the completed audit
When the audit comes back, do not just pay it or fight it. Read it against your own records line by line: does the payroll match, are the class codes right, are the subcontractor charges backed by missing certificates, is the owner treatment correct? Most audits resolve into a few explainable lines. Some of what looks like an overcharge is a real exposure you owe; some is a correctable error. Sorting which is which is the whole task.
Questions, disputes, and deadlines
If a figure genuinely does not match your records, you can ask the carrier to review it, and if a real dispute remains, the carrier and Oregon have defined processes. Those steps are time-sensitive, and the specific deadlines change, so confirm the current process with your carrier or the Oregon Workers’ Compensation Division rather than relying on a remembered number. Act promptly; disputes have windows.
Industry-specific audit help
The audit questions differ by trade. If you are a contractor or a restaurant, our industry audit explainers go deeper on the class codes and exposures specific to your work: contractor workers’ comp audits and restaurant workers’ comp audits. This guide is the general Oregon foundation they build on.
How we help
If you have an audit coming or a bill you do not understand, a policy and cost review helps you organize the records, read the audit against your numbers, and separate what you genuinely owe from what should be reconciled. We do not promise a reversal, and we do not treat every charge as a fight, but we do make sure you are not overpaying for an error, and that the next audit does not surprise you.