Seasonal Payroll and Your Experience Mod

Updated September 29, 2026

Your busy season is winding down. The crews you added for spring and summer are thinning out, and after the renewal that follows, the audit of those months becomes the payroll behind a future workers’ comp EMR (experience modification rate). Here is the direct answer on seasonal payroll and your experience mod: the swings themselves don’t count against you. What counts is whether the payroll on your worksheet matches the payroll you actually paid, sitting in the class codes that describe the work.

That’s true whether you run landscaping crews, roofing crews, a paving outfit or a snow removal operation. A crew of forty in July and eight in January produces different expected losses, and the rating adjusts for that. The trouble starts when the numbers describing those crews are wrong.

Expected losses follow the payroll you actually paid

Your mod compares your actual losses (what your claims cost) to your expected losses. Expected losses are what a typical contractor in your line of work, with your payroll, would be expected to lose to claims. NCCI builds them one class code at a time (a class code is the classification that groups similar operations, like roofing or landscaping, for rating). Each code has an expected loss rate, and the bureau multiplies that rate by the payroll reported under the code.

So a big summer crew raises your expected losses for that year, and a small winter crew lowers them. The baseline grows and shrinks with the payroll. A seasonal business is measured against a seasonal baseline, which is the fair comparison, as long as the payroll behind it is correct.

Payroll also affects how much your own claims count. NCCI’s primer on experience rating says the larger an employer, the more its mod is influenced by its own experience. Your payroll size feeds that weighting through your expected losses. How your mod is calculated walks through the full formula if you want the rest of it.

How seasonal payroll reaches your workers’ comp experience mod

Your payroll doesn’t go to the bureau the day you run it. Your carrier reports it on a unit statistical report, the filing that sends your payroll and claims for one policy period to the rating bureau. NCCI says the carrier isn’t required to file that report until 18 months after the policy started, which gives the carrier time to value claims and prepare the report.

The payroll that should appear is your audited payroll: what the carrier’s premium audit found you actually paid, by class code, after the policy year closed. In NCCI states, if NCCI builds your mod before that audited payroll arrives, it issues what it calls a contingent mod and revises it once the audited figures come in. Ask your agent whether your current mod is contingent. If it is, that’s worth knowing before you quote the number on a bid form.

The timing matters for planning. Under NCCI’s plan, a policy counts in your experience period only if it started at least 21 months before the mod’s rating effective date. The busy season you just finished first counts in the mod that takes effect about two years after the start of the policy it fell in. On a January 1 renewal, for example, work from a policy that started January 1, 2026 first shows up in the January 1, 2028 mod. It then stays for three ratings. The unit stat calendar covers how to line up a correction with that schedule.

Where seasonal payroll goes wrong on the worksheet

Errors here can move your mod up or down. There’s no way to know which way yours runs without putting the worksheet next to your records.

A year’s payroll doesn’t match the audit. Payroll listed for a class code on your experience rating worksheet should match the audited payroll for that code and year. A seasonal crew missed at audit, an audit correction that never reached the bureau, or a keying error at the carrier all change your expected losses. Understated payroll shrinks the baseline, so your claims look worse against it. Overstated payroll does the reverse, and costs you in premium.

A crew’s payroll sits in the wrong code for the season. Plenty of seasonal contractors change what their crews do when the weather turns. The landscaping crew plows snow. The roofing crew picks up other work in the slow months. Each operation carries its own expected loss rate, so the code that payroll lands in matters. In North Carolina, for example, the Rate Bureau’s basic manual says a construction operation gets its own classification only if separate payroll records are kept for it. Dividing one worker’s payroll between codes takes records of actual time spent. Estimated or percentage splits are not permitted, and without those records the worker’s whole payroll goes to the highest rated code that applies. If your time records don’t show who did what in which season, the payroll can’t be split the way the work actually was.

Office payroll sits in a field code, or the reverse. This one catches people because the premium and the mod move in opposite directions. A clerical office classification has an expected loss rate that is a small fraction of a field construction code’s, as the North Carolina Rate Bureau’s own rate tables show. Put office payroll in a field code and your premium goes up, but your expected losses go up too, which lowers your mod. Correct it and your premium drops, but your mod can rise. The reverse error (field payroll in the clerical code) lowers premium and raises the mod, and an auditor who finds it can reassign the payroll. Rating manuals also put conditions on the clerical code. North Carolina’s, for example, limits it to office duties in a work area physically separated from the operating hazards.

Don’t try to push payroll in either direction. Put each dollar where the manual puts it, and know which way a correction will move both your premium and your mod before you ask for it. If you’re close to the line your GC sets, that second part matters.

What to check before your next renewal

Start with your current worksheet. If you don’t have it, here’s how to get it. Then work through the payroll rows.

• Compare the payroll for each class code and each of the three years against your premium audit statements for those years.
• Look for a seasonal operation that doesn’t appear at all, or that appears under a code describing different work.
• Check whether crews that switch work by season have time records that support the split.
• Check whether office and field payroll are separated the way your operations actually run.
• Ask your agent whether your mod is contingent and, if it is, when the audited payroll is expected to reach the bureau.

Classification and payroll-division rules are set state by state, either through NCCI’s manual as your state adopted it or by your state’s own rating bureau. North Carolina, California, New York, Pennsylvania, Delaware and New Jersey are among the states with their own bureaus. Ask your agent to confirm the rule for your state rather than relying on the North Carolina wording above.

Payroll and class code problems sit alongside the claim problems in the ten worksheet errors worth checking. A full check covers both, and the documents list for a verification already includes payroll by class code for each year.

Checking your numbers before the next worksheet lands

The free EMR Cost & Bid Check calculator shows what your current mod is costing you against common thresholds. A full verification compares every payroll row and every claim on your worksheet against your audits and loss runs, and tells you exactly what to send your agent or carrier. It’s a flat fee, no contingency, and the savings are yours. Get on the waitlist to be first in line.