Glossary

Experience modification rate (EMR)

A multiplier on workers' compensation premium comparing an employer's actual claim losses with the losses expected for its industry and size.

Also called: EMR, experience mod, X-mod, experience modification factor, mod rate

An experience mod is a multiplier applied to workers' compensation premium to reflect your claim history against others in your class. A mod of 1.00 is average, below 1.00 earns a credit and above 1.00 is a debit. With a $100,000 manual premium, a 1.15 mod produces $115,000 and a 0.85 mod produces $85,000 (a hypothetical).

Under the NCCI plan, the experience period is generally three policy years that skip the most recent one. For a policy effective January 1, 2027, that means the policies effective in 2023, 2024 and 2025. Each claim is split at a split point into a primary part, counted in full because frequency predicts future claims, and an excess part, counted at reduced weight. There is no single national split point any more; NCCI sets them state by state in each rate filing.

Not every state uses NCCI's plan. California, Delaware, Michigan, New Jersey, New York and Pennsylvania have their own rating bureaus, as do the four monopolistic states. The premium size that triggers experience rating also varies by state.

Prospective customers and general contractors often ask for the mod, so check the worksheet for errors: open claims that should be closed, claims that belong to another entity, and wrong class codes. The experience modification rate (EMR) explained walks through the formula, and the Experience mod (EMR) calculator tests what a claim does to your mod.

Last reviewed October 10, 2026

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Related terms

NCCI The National Council on Compensation Insurance, the rating and data organization behind workers' comp class codes, loss costs and mods in most states. Class code The numeric code that classifies a business's operations for rating, setting the workers' compensation rate per $100 of payroll. Workers' compensation State-mandated no-fault insurance that pays medical care and part of lost wages for work-related injuries, in exchange for limits on employee lawsuits. Premium audit The insurer's after-the-fact review of payroll, sales or other exposures that replaces the pricing estimates, producing an additional or return premium. DART rate An OSHA incident rate counting injury and illness cases that caused days away from work, restricted duty or a job transfer, per 100 full-time workers.

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EMPLOYERS Reno-based workers' comp specialist for lower-hazard small businesses, sold through agents and online through its Cerity brand; rated A (Excellent) by AM Best. Federated Insurance Minnesota mutual founded in 1904 that sells property, casualty, life and bonds directly to businesses in select industries, backed by 500+ trade associations. Great American Insurance Group Cincinnati specialty insurer owned by American Financial Group (NYSE: AFG), running 30-plus niche units in comp, trucking, construction, crime and marine. ICW Group Privately held San Diego insurer known for workers' comp in 22 states and commercial earthquake cover, now adding E&S excess and California commercial lines. New York State Insurance Fund (NYSIF) New York's state agency fund for workers' comp, disability and paid family leave. It competes with private carriers and must take any employer that applies. Progressive Commercial The largest U.S. commercial auto insurer, for work vehicles, trucks and tow trucks, sold by agents and online. Most other business lines come from partners.

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Related tools

Experience mod (EMR) calculator Recalculate an NCCI experience mod with the split-rating formula and see what each claim adds and costs over the three years it stays in your mod. OSHA incident rate calculator (TRIR and DART) Calculate TRIR, DART rate, lost-time case rate and severity rate from your OSHA 300 log and hours worked, and compare them with an industry rate. Workers' comp premium calculator Build a workers' comp premium step by step from payroll, class code rates, your experience mod, credits, discounts, fees and assessments.

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