Workers' Comp Premium Audit: Records to Pull and How to Prepare

Every workers' compensation policy is priced twice. At the start of the policy period, the carrier charges a deposit or estimated premium based on the payroll you expect to pay in each classification. After the period ends, the carrier audits your actual payroll and calculates the final premium. If actual payroll was higher than the estimate, or landed in more expensive classifications, you get a bill for additional premium. If it was lower, you get a return.

The workers' comp premium audit is where errors in classification, payroll reporting and subcontractor paperwork turn into money. Most of the records the auditor asks for sit with HR, payroll and accounting, which makes preparation an HR job as much as a finance one. This guide covers what the auditor checks, the records to pull, the payroll rules that most often change the result, and how to dispute findings you disagree with. For the underlying formula, see our premium calculation guide.

What the Auditor Checks and Why It Changes Your Premium

The standard workers' compensation policy gives the carrier the right to examine and audit the records that relate to the policy, including payroll records, ledgers, tax reports, disbursement records and contracts. The audit may be done in person, by phone or video, or by a mail or online questionnaire the employer completes, depending on the size of the policy and the carrier's practice.

Whatever the format, the auditor is answering four questions:

1. How much payroll did you actually pay? Total remuneration for the policy period, reconciled to tax filings.
2. Which classification does each dollar belong in? The auditor checks that the codes on the policy match your operations and that employees outside the governing class qualify for their codes. Expect questions about anyone in a clerical, outside sales or telecommuter code, and about employees whose payroll is split between codes.
3. What can be excluded? Items such as the premium portion of overtime, where the rules allow it, come out of the payroll base, but only with the right records.
4. Who else worked for you? Payments to subcontractors and independent contractors are reviewed to see whether the workers were covered by their own insurance.

Because premium is calculated per $100 of payroll in each classification, the audit can move your bill in several ways at once: more payroll than estimated, payroll moved into a higher-rated code, exclusions disallowed, or uninsured subcontractors added. The audited payroll also becomes the data used later in experience rating, so accuracy matters beyond the current bill.

Records to Pull

Start gathering records before the auditor's appointment letter or questionnaire arrives. A typical request includes:

Payroll records

• Payroll registers or journals for the full policy period, by employee, showing gross pay, regular pay, overtime pay and hours.
• Payroll summarized by classification code, with a list of employees in each code and their job titles.
• Federal Form 941 quarterly returns for the quarters that overlap the policy period, plus Form 940 and Forms W-2/W-3 where requested.
• State unemployment insurance wage reports for the same quarters.
• Officer, owner and partner payroll, along with any exclusion or election forms filed under your state's rules for owners.

Payments outside payroll

• General ledger and cash disbursement records, so the auditor can see payments to people who are not on payroll.
• Forms 1099-NEC and a vendor list showing payments to individuals and subcontractors.
• Certificates of insurance for every subcontractor, showing workers' comp coverage in force for the dates the work was performed.
• Contracts or invoices that separate labor from materials, where a subcontractor's payroll may need to be reconstructed.

Supporting documents

• Job descriptions for employees in clerical, outside sales and other non-governing codes.
• Time records by classification for employees whose payroll is split between codes.
• A description of your operations, including any new services, locations or states added during the period.

Reconcile the totals before you hand anything over. Payroll by class should tie to the payroll register, and the register should tie to the 941s and state wage reports. Differences you can explain in advance, such as a timing difference at quarter end, will not become audit findings.

Overtime Premium and Other Payroll Exclusions

Not every dollar of pay is premium-bearing. The rules differ by bureau, and the details matter, so treat this section as the pattern and confirm your state's rules with your agent or carrier.

Overtime under NCCI-based rules

In the NCCI-based rules used in most states, the extra pay for overtime is excluded from the payroll on which premium is calculated, provided your books show overtime pay separately by employee and summarized by classification. Only the premium portion comes out, not the straight-time pay for the overtime hours. For time-and-a-half, that is the extra half. For example, an employee paid $20 an hour who works 10 overtime hours at $30 earns $300 for those hours; $200 stays in payroll and $100 is excluded.

Points to watch:

• Records are everything. If your payroll system lumps overtime into one gross figure with no breakdown, the exclusion is hard to support. Where records show total overtime pay at time-and-a-half in one amount, the North Carolina manual, which follows NCCI's text, excludes one-third of it; at double time, one-half.
• Shift differentials are not overtime. A higher rate for night or weekend shifts that is part of the normal schedule is incentive pay and stays in payroll.
• No rate increase, no exclusion. An employee who works more than 40 hours but is paid the same rate for every hour generates no excludable overtime premium.

Bureaus that treat overtime differently

Overtime treatment is not uniform. Pennsylvania's workers' compensation manual, published by the Pennsylvania Compensation Rating Bureau, lists extra pay for overtime work as an inclusion in remuneration, so the full amount is premium-bearing there. Other independent bureaus and the monopolistic state funds have their own rules. Multi-state employers should confirm the overtime rule for each state on the policy.

Other common exclusions

NCCI-based manuals also exclude items such as tips and gratuities, and employer contributions to group insurance and group pension plans, while including most other forms of pay, such as bonuses, commissions, and holiday, vacation and sick pay. Ask your carrier for its payroll reporting guide for your state, and map each pay code in your payroll system to "included" or "excluded" before the audit, not during it.

Subcontractors Without Certificates of Insurance

Subcontractor findings produce some of the largest audit adjustments. The general rule in NCCI-based manuals is that a contractor is responsible for the workers' comp premium on uninsured subcontractors' employees. Unless you can show that a subcontractor had its own workers' comp coverage in force for the work, the auditor will add premium for that subcontractor's workers to your policy.

How the auditor calculates it depends on what you can document. If you can provide the subcontractor's payroll records, that payroll is used. If you cannot, and the contract does not separate labor from materials, the full contract price may be treated as payroll, subject to the bureau's rules.

To protect yourself:

• Collect a certificate of insurance before work starts, and make sure its dates cover the full period of the work. A certificate that expired midway is a common finding.
• Calendar expiration dates and request renewals before they lapse.
• Ask for invoices that split labor and materials, so any uninsured labor can be measured accurately.
• Review 1099 payees each quarter. An individual paid regularly with no certificate is either an uninsured subcontractor or a misclassified employee.

That last point is worth a separate review. Workers you treat as independent contractors may be considered employees under your state's workers' comp law, and the auditor may add their pay to your payroll. Our article on employees vs. independent contractors covers the tests.

Disputing Audit Findings

When the audit bill arrives, review the auditor's worksheet line by line before paying. Compare payroll by class with your own report, check that exclusions you documented were applied, and confirm any subcontractor charges against your certificates.

If something is wrong:

5. Ask the carrier for an audit review. Explain the error in writing and attach the documents that support your position: certificates, time records, overtime detail or job descriptions. Many disputes end here, especially when the issue is missing paperwork.
6. Pay the undisputed portion. Separating the undisputed premium from the amount in question keeps the policy in good standing.
7. Use the bureau's dispute process if needed. In most NCCI states, NCCI's filed Dispute Resolution Process is available for disputes about how the manual rules, such as classification or experience rating, were applied. Before filing, the policyholder must try to resolve the dispute with the carrier, pay the undisputed premium, and provide an estimate of the disputed premium with a written explanation of the calculation. NCCI assigns a dispute consultant, and if the parties still cannot agree, the dispute can go to the state's workers' compensation appeals board or committee. Whether disputed premium can be held in abeyance, and how a decision is appealed, depend on state law.

Policies written through a state's assigned risk plan follow different dispute rules, and independent bureau states have their own procedures. Your agent, the state bureau or the state insurance department can tell you which process applies.

Keep in mind that the carrier's right to audit does not end with the policy period, and a refusal to cooperate with the audit can lead to additional charges in states that have approved an audit noncompliance endorsement. Responding promptly is always cheaper than not responding.

A Year-Round Audit-Readiness Calendar

Audit preparation is easiest when it is a routine rather than a scramble.

For hands-on training in this area, see our premium control and audit program, and our broader workers' comp training for HR.

Build Workers' Comp Premium Skills on Your Team

A clean audit depends on people in HR, payroll and finance who understand how premiums are determined and which records support them. The Workers' Compensation Training & Certification program covers how premiums are determined and how employers can affect them, along with injury reporting, claims, return to work, and injury and employment records. It is self-paced and online, includes one year of access and free updates when the law changes, and offers an optional exam for the Certified Workers' Compensation Administrator credential.

Frequently Asked Questions

What is a workers' comp premium audit?

A workers' comp premium audit is the carrier's review of your actual payroll and operations after the policy period ends. Your premium at the start of the policy is based on estimated payroll by classification. The audit replaces those estimates with actual figures, checks that payroll is in the right classification codes, applies allowed exclusions, and adds any uninsured subcontractors. The result is a final premium, which produces either an additional bill or a return of premium.

What records do I need for a workers' compensation audit?

Typically: payroll registers by employee for the policy period, payroll summarized by classification code, Form 941 quarterly returns, state unemployment wage reports, owner and officer payroll, the general ledger or disbursement records, Forms 1099, and certificates of insurance for subcontractors. If you split employees between codes, have time records by classification. If you exclude overtime premium, have overtime pay shown separately by employee and class.

Is overtime included in workers' comp payroll?

In NCCI-based rules used in most states, the extra pay for overtime is excluded from premium payroll, but the straight-time portion is included, and only if your records show overtime pay separately by employee and summarized by classification. Not every state follows that rule. Pennsylvania's manual, for example, includes extra pay for overtime in remuneration. Confirm the rule for each state on your policy with your agent or carrier.

Why did my workers' comp audit result in a bill?

The most common reasons are actual payroll higher than the estimate, payroll moved into a higher-rated classification, subcontractors without proof of workers' comp coverage, or exclusions such as overtime premium disallowed for lack of records. Review the auditor's worksheet to see which applies. If payroll grew during the year, updating the estimate mid-term with your agent can reduce the size of the bill at audit, though not the premium owed on the actual payroll.

How do I dispute a workers' comp audit?

Start with the carrier: explain the error in writing, attach supporting documents and pay the undisputed portion. If you cannot resolve it and your state uses NCCI's rules, NCCI's Dispute Resolution Process is available in most NCCI states for disputes about how manual rules such as classification were applied, with review by a state appeals board or committee if needed. Assigned risk policies and independent bureau states have their own procedures.

Can I refuse a workers' comp premium audit?

The audit is a condition of the standard policy, which gives the carrier the right to examine the records related to it. Refusing or ignoring audit requests can lead to additional charges, including an audit noncompliance charge in states that have approved that endorsement. If the timing is a problem, ask the auditor to reschedule or to use a remote or questionnaire format.