The experience modification is where a large share of your workers’ compensation cost is quietly decided, and most employers have never read the worksheet that produces it. It multiplies your premium up or down based on how your claims compare to what is expected for a business your size and class. You cannot flip it overnight, but you can influence what feeds it, and you can check whether the data behind it is even correct. This guide explains the factor in plain language.
The short version
- The mod multiplies your premium up or down; 1.00 is average.
- It compares your losses to what is expected for your size and class.
- Frequency usually moves it more than one large claim.
- It is managed over time, through safety and return-to-work, not overnight.
- The worksheet can carry stale data, and correcting it is legitimate.
What the experience modification is
The experience modification, often called the mod or the ex-mod, is a factor applied to your workers’ compensation premium after the class-code rates and payroll produce a base figure. A mod of 1.00 is neutral: your loss experience matches what is expected for employers of your size and classification. A mod below 1.00 credits you for better-than-expected experience and lowers your premium; a mod above 1.00 debits you and raises it. It is, in effect, a report card that turns your own claims history into a multiplier on price.
When the mod applies
Not every business is experience-rated. A company has to generate enough premium over the rating period to qualify; below that eligibility threshold, a business pays manual rates and is not individually rated on its own losses. The threshold is set by the rating organization and changes over time, so the practical step is to confirm with your carrier or NCCI whether you are experience-rated at all before trying to interpret a factor. Many small employers are surprised to learn they are not yet rated, or have just crossed into being rated.
What data feeds the calculation
The mod is built from your own payroll and loss data over an experience period, typically covering several past policy years and excluding the most recent one, which is not yet mature. Two features of the formula matter more than any other:
- Payroll by class sets the expected losses, the benchmark your actual losses are measured against.
- Reported losses, both paid amounts and open reserves, are your actual experience in the formula.
Because both come from data reported by carriers, an error in either, a misreported payroll, a claim reserve that never got updated, flows straight into your mod.
Why frequency matters more than severity
This surprises people: several small claims can raise your mod more than one large one. The experience rating formula splits each loss into a primary portion and an excess portion, and it weights the primary portion, the first slice of every claim, far more heavily. The reason is predictive. A pattern of frequent claims says more about future cost than a single severe accident that may never repeat. So a business with a run of minor injuries can carry a higher mod than a business with one serious but isolated claim. The lever that follows is preventing claims from happening at all, not just controlling the big ones.
Reading the mod worksheet
The worksheet behind your mod lists the claims and payroll driving the factor, and it rewards a careful read. The most common and correctable problem is a stale reserve: a claim that was reserved high early, then closed for far less, but still shows the high figure in your experience. That inflated reserve can weigh on your mod for the years it sits in the experience period. Confirming that closed claims are valued at what they actually cost, and that the payroll and classifications are right, is legitimate and sometimes overlooked. This is data accuracy, not gaming the number.
What you can actually influence
You do not flip the mod; you manage what feeds it, over time:
- Safety practices that reduce how often injuries happen, which the formula weights most.
- Prompt claim reporting, because delayed claims tend to cost more and reserve higher.
- Return-to-work, getting injured workers back to appropriate duty to shorten claims.
- Data accuracy, correcting stale reserves and reporting errors on the worksheet.
None of these is a switch, and none is guaranteed. Done consistently, they move the factor in the right direction over the rating period.
Return-to-work programs in Oregon
Getting an injured worker back to modified duty shortens a claim, which helps your experience over time, and Oregon supports it directly. The Workers’ Compensation Division runs return-to-work programs, the Employer-at-Injury Program and the Preferred Worker Program, that can offset wages and worksite costs for eligible situations, accessed through your insurer. The caps and rules are set by regulation, so confirm current terms at wcd.oregon.gov. These are state programs, not carrier promotions, and the benefit is specific to the situation.
Mod, rate, and premium are not the same
Keep three things straight. The class code and its filed rate set the base price on your payroll. The experience modification adjusts that base up or down. The premium is the result, after the mod and other credits and assessments. Your premium can rise while your rate is flat because the mod moved, and your mod can be wrong while your rate looks fine. Knowing which lever you are actually pulling is the difference between managing your cost and guessing at it.
How we help
If your mod is above 1.00 and no one has explained why, a policy and cost review reads the worksheet with you: it checks the losses and payroll behind the factor, flags a stale reserve or reporting error worth disputing, and separates what is a real signal to manage from what is correctable data. We do not promise a number before we have read it, and the mod moves over time rather than overnight, but knowing what is driving it is how you stop overpaying for someone else’s data error. If you are with SAIF and want independent eyes on the mod, that review is the place to start, and you can change your servicing agent without changing the policy.