Workers Compensation Experience Modification Factors in 2026
The experience modification factor is the most personal number in a commercial insurance program, and the most frequently misread. It is neither a credit an employer simply earns nor a penalty a carrier imposes. It is a statistical comparison: the losses an employer of a given size and class actually incurred over a three-year window, measured against the losses the rating bureau expected a similar employer to incur. A mod of 1.00 is the industry’s shorthand for average. Below that, the employer’s experience has run better than expected; above it, worse. The factor multiplies manual premium, which means it works quietly in both directions — rewarding discipline and compounding neglect long after the underlying claim has closed.
The mechanics matter, because the mod does not treat every dollar of loss the same way. The National Council on Compensation Insurance, whose experience-rating plan governs 36 states including Tennessee, splits each claim into a primary portion and an excess portion at a defined threshold. For years that split point sat at a uniform $18,500. Beginning with rating values effective on or after November 1, 2023, NCCI moved to state-specific split points that reflect each state’s own loss data — a range that runs from roughly $9,500 in Oregon to $38,000 in Louisiana. The primary portion of a loss counts in full; the excess portion is steeply reduced. The design is deliberate. Frequency — many small claims — moves a mod far more than a single severe one. An employer with a scatter of minor, preventable injuries can carry a worse factor than a peer with one serious but isolated claim.
That construction is why the mod is best understood as a forward-looking instrument rather than a rear-view mirror. The three-year experience period lags, excluding the most recent policy year, so a claim reported today does not simply cost its indemnity and medical dollars. It sits in the rating calculation for three consecutive annual mods, silently repricing every renewal it touches. The exposure an employer most controls, then, is not the premium quoted this year but the loss runs feeding the calculation eighteen months from now.
Consider the arithmetic in plain terms. A contractor with five strained backs and cut hands over a rating period, none individually severe, can carry a factor well above 1.00 because each of those losses lands almost entirely in the primary bucket that the plan counts in full. A neighboring firm with a single, tragic but isolated claim may fare better, because the bulk of that one large loss falls into the reduced excess portion. The plan is not indifferent to severity, but it is engineered to reward employers who prevent the routine, repeated injury — and to hold accountable those who tolerate it as a cost of doing business.
The surrounding market gives that control real leverage right now. Workers compensation remains the most profitable major property-casualty line. NCCI reported a calendar-year 2025 combined ratio of 91 percent for private carriers, against roughly 93 percent for the industry overall, alongside an estimated $14 billion in redundant reserves. Net written premium slipped to $41.6 billion, and approved loss-cost filings are expected to lower premiums by an average of 5.0 percent into 2026 — though individual state filings ranged from a 15.6 percent decrease to a 21.6 percent increase. Lost-time claim frequency fell about 2 percent even as medical and indemnity severity each climbed 4 percent.
Softening loss costs and rising severity pull in opposite directions, and the experience mod is where that tension lands on a specific employer. When bureau loss costs fall, the manual premium base shrinks for everyone; the differentiator that remains is the mod. Two employers in the same class and state, quoted off the same declining loss costs, can pay materially different premiums entirely because one has managed frequency and the other has not. In a soft market, the mod is not a footnote to the pricing. Increasingly, it is the pricing.
The disciplined levers are unglamorous and durable: prompt claim reporting, a genuine return-to-work program that converts lost-time claims into medical-only ones, reserve reviews before the unit-statistical filing date locks a claim into the calculation, and periodic audits of payroll classification, since a misclassified code inflates expected losses and distorts the factor in ways that have nothing to do with safety. Each is a governance habit more than a purchase, and each compounds over the same three-year window the rating plan measures.
This is the work our four-step Strategic Process is built to make routine. Strategic Discovery surfaces the loss runs, class codes, and open reserves that actually drive the factor. Risk Assessment models where frequency, not severity, is quietly setting the number. Solution Design aligns program structure, return-to-work protocols, and reserve discipline with the rating window. Ongoing Optimization keeps the file accurate between renewals, so the mod reflects the business the owner is actually running. The experience modification factor rewards employers who treat it as something they own rather than something that happens to them, and in a market this competitive, that ownership is where the real advantage is hidden.
Sources: Risk & Insurance — Workers’ Comp Remains Profitable as Premium Dips and Severity Climbs; USI — Key Changes to NCCI’s Experience Modification Factor; NCCI — ABCs of Experience Rating; Jencap — NCCI Experience Mod Methodology Changes; PIA Northeast — NCCI 2026 Loss Cost Decrease Approved; Gallagher — Upcoming Workers’ Compensation Updates
— Ryan Mefford, President & Risk Advisor