What Is a Workers' Comp X-Mod?
Your experience modification (X-Mod) is a single number that multiplies your workers' comp premium up or down based on your past claims. An X-Mod of 1.00 is average. Below 1.00 is a credit (you pay less than the base rate); above 1.00 is a surcharge (you pay more). It rewards safe, low-claim employers and penalizes those with frequent or severe losses.
How is the X-Mod calculated?
In California, the WCIRB compares your actual losses over a three-year window (excluding the most recent year) to the expected losses for businesses with your class codes and payroll. Two ideas drive it:
- Frequency matters more than severity. Several small claims hurt your X-Mod more than one large claim, because frequency signals ongoing risk.
- Primary vs. excess losses. The first dollars of each claim ("primary") weigh more heavily than the large tail of a single big claim.
What raises your X-Mod?
- A pattern of claims (frequency), even small ones.
- Claims that stay open with high reserves.
- Slow injury reporting and no return-to-work program.
What lowers it?
- A documented return-to-work / light-duty program that shortens claims.
- Fast injury reporting and active claims management.
- Accurate class codes and payroll so expected losses are right.
- Correcting reserve or unit-statistical errors with the WCIRB.
Can an X-Mod be wrong?
Yes — and it's worth checking. Overstated open reserves, misreported payroll, or wrong class codes can inflate your X-Mod. A broker can pull your experience-rating worksheet, spot errors, and request a correction. Even a small reduction compounds across your whole premium.
Want your X-Mod reviewed, or a fresh workers' comp quote?
FAQ
Is an X-Mod below 1.00 good?
Yes. Below 1.00 means you pay less than the base rate for your class — a credit that reflects better-than-expected loss experience.
How long does a claim affect my X-Mod?
Generally three years. A claim enters your experience period and rolls off after about three years, which is why a strong return-to-work program pays off over time.
Who calculates the California X-Mod?
The WCIRB (Workers' Compensation Insurance Rating Bureau of California) publishes experience modifications; carriers apply them to your premium.
General information from Focus West Insurance Solutions (CA Lic. #0M32679), not legal or coverage advice; your actual experience modification is determined by the WCIRB. Related: workers' comp in California · X-Mod in the glossary · WC quick quote.