On this page
Every workers compensation policy gets audited. It usually happens a few months after the policy year ends, and many small business owners first hear about it when a letter arrives asking for payroll records. The audit isn’t a punishment. It’s the carrier’s end-of-year true-up, and handled well it’s a non-event. Handled carelessly, it can lock in overcharges.
Why audits happen
Workers comp premiums are based on estimated payroll and job classifications set at the start of the policy year. Your business pays a deposit premium based on those estimates. The audit compares the estimates to what actually happened: real payroll, real job duties, real subcontractor payments.
The carrier then recalculates the year’s premium. If your actual payroll was higher than estimated, you owe additional premium. If it was lower, you get a refund. Either way, the final number should reflect reality. The audit exists because reality rarely matches the estimate.
What the auditor checks
The auditor reviews your payroll records by employee and by job classification, since different job classes carry different rates. An office worker costs far less to insure than a roofer, so correct classification is where most of the audit’s money moves.
Typical items on the auditor’s list:
- Payroll summaries and quarterly tax filings, including 941 forms and state unemployment reports.
- Employee job descriptions matched against the classification codes on the policy.
- Overtime records. In most states, the premium portion of overtime can be excluded from workers comp payroll, but only if your records show it separately.
- Subcontractor payments and their certificates of insurance. If a subcontractor can’t produce a valid certificate, their payments may be counted as your payroll.
- Changes in business operations during the year, like new services or new locations.
Audits come in three forms: by mail, by phone, or in person. Small policies with simple payroll often get mail or phone audits. Larger or more complex businesses get an on-site visit.
The mistakes that cost money
Several common errors inflate the final premium, and all of them are correctable.
Wrong class codes are the biggest one. When job duties are described vaguely, auditors default to the higher-rate code. An employee who does office work and occasional site visits can end up classified entirely as field labor if the records don’t separate the duties.
Overtime counted at full value is another. If you paid time and a half but your records don’t break out the overtime premium, the auditor may include the full amount in payroll. Keeping overtime tracked separately is one of the simplest ways to lower the audited premium.
Missing subcontractor certificates are the most expensive surprise. No certificate at audit time usually means the subcontractor’s payments get added to your payroll at your highest rate. Collecting certificates before you pay anyone is standard practice for a reason.
Ignoring the audit entirely is the worst option. Some carriers apply estimated or penalty rates when you don’t cooperate, and those estimates are never in your favor.
How to prepare
Preparation starts months before the audit letter arrives. Set up your payroll system to track workers comp codes by employee from the start of the policy year, not at the end. Keep payroll broken out by job duty, not one lump sum.
Have these documents ready: payroll summaries, 941s, state unemployment reports, job descriptions, overtime records, and certificates of insurance for every subcontractor. Review your policy’s description of operations before the audit and update it if the business changed during the year.
If the audit bill looks wrong, dispute it. Auditors make mistakes, and carriers have formal dispute processes. An independent review of the audit math, sometimes called a premium audit review, can catch misclassifications and recover overcharges retroactively.
Reducing audit surprises going forward
One option worth asking your carrier about is pay-as-you-go workers comp, where premiums are tied to actual payroll each pay period instead of an annual estimate. That nearly eliminates the audit true-up, and it’s especially useful for businesses with seasonal or fluctuating payroll.
Understanding your workers comp insurance costs by industry also helps you spot when an audit result looks out of line. And keeping your whole business insurance program current, including accurate operations descriptions, means the audit starts from correct assumptions instead of wrong ones.
