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What Is an Experience Modification Factor?

When I set up workers comp for a new business, the mod is usually the first thing I explain — not because they have a bad one. Every new business starts at 1.0. I explain it because most business owners don't know it exists until renewal, when they find out it's been moving without them. A 1.0 can become a 1.4 after two rough claims years, and once you're there, the conversation with carriers gets harder fast.

Here's how the mod works, what moves it, and what you can actually do to keep it from working against you.

What the Experience Mod Actually Is

Your experience modification factor — also called an experience mod or EMR — is a multiplier applied to your workers comp premium. It's calculated by the Minnesota Workers Compensation Insurers Association (MWCIA), which is the state rating bureau that processes mod calculations for all eligible employers in Minnesota.

The calculation compares your actual workers comp losses to the losses that would be statistically expected for a business of your size and industry class. The result is a ratio:

For most small businesses, the difference between a 0.85 mod and a 1.25 mod translates to thousands of dollars per year in premium — and the gap compounds at renewal if the underlying claim situation doesn't change.

How the Calculation Works — and Why Frequency Matters More Than Severity

The mod is based on a three-year experience period — your three most recently completed policy years, excluding the current year. MWCIA publishes your updated mod once per year, and it follows you to every carrier you quote.

The part most business owners don't know: claim frequency is weighted more heavily than claim severity. Three small claims of $5,000 each will damage your mod more than one large claim of $15,000. The formula is designed this way intentionally — frequency is considered a better indicator of your safety culture than the size of any single incident.

What I tell every new business: Your mod starts at 1.0. The goal isn't to get it lower immediately — the goal is to understand that one bad claim can spike it for three years, and three bad claims can make you very difficult to place in the standard market. Frequency is the thing to manage.

When Does Your Business Qualify for a Mod?

Not every business has an experience mod. In Minnesota, you typically become eligible once you're generating roughly $5,000 or more in annual workers comp premium — enough for the calculation to be statistically credible. Most businesses hit that threshold within two to three years of operation.

New businesses start at a 1.0 neutral mod. MWCIA calculates and issues your first mod once you cross the eligibility threshold. After that, it's recalculated annually at each policy renewal.

What Moves Your Mod — and What You Can Do About It

What pushes it higher

What brings it down — or keeps it down

Why Your Mod Follows You to Every Carrier

A question I get from business owners who've had a bad mod year: "Can I just switch carriers and start over?" No. The mod is filed with MWCIA and is public information that every admitted workers comp carrier in Minnesota can see. When you get a new quote, the carrier looks up your MWCIA mod and applies it to their base rate. You can't leave a bad mod behind by changing insurers — you can only improve it over time.

What you can do is work with an independent agent who knows which carriers look harder at claim type versus claim history, and who can help you document what you've actually done about the underlying issue. There's a real difference between carriers on this. Some will give real credit for a documented safety program and a clean recent record. Others won't. That's worth knowing before you start shopping.

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Common Questions

Experience Mod FAQ

An experience mod (or EMR) is a multiplier applied to your workers comp premium. It compares your actual claim losses to what's statistically expected for a business of your size and industry. A 1.0 is neutral. Above 1.0 means a premium surcharge; below 1.0 means a credit. In Minnesota, mods are calculated by the Minnesota Workers Compensation Insurers Association (MWCIA).
The mod compares your actual workers comp losses over a three-year experience period to the expected losses for your payroll size and industry class. Claim frequency is weighted more heavily than severity — multiple small claims hurt your mod more than one large claim of the same total cost. The most recently completed policy year is excluded from the calculation.
In Minnesota, businesses typically receive their first mod after two to three years of workers comp coverage and enough payroll to meet MWCIA's credibility threshold. New businesses start at a neutral 1.0 mod. Once eligible, your mod is recalculated annually.
Workers comp claims stay in your three-year experience period for three consecutive policy years. A claim filed today will affect your mod at the next three annual renewals. Because the experience period excludes the current year, the full impact can feel longer than three years from the claim date.
No. Your mod is calculated by MWCIA and is visible to every admitted workers comp carrier in Minnesota. Switching carriers doesn't reset your mod — every carrier you quote will apply the same MWCIA number to their base rate. The only way to improve your mod is to improve your claims history over time.

Setting up workers comp — or wondering why your mod moved?

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Last updated: June 8, 2026