Premium factors
Your experience modification factor — the X-Mod — is one of the most important numbers on a California Workers' Compensation policy. It adjusts your premium up or down based on your claims history compared to other California employers in the same industry classifications. A strong X-Mod can save a statewide business tens of thousands of dollars per year.
The Workers' Compensation Insurance Rating Bureau of California (WCIRB) calculates X-Mods for eligible employers. The factor compares your actual losses — both paid and reserved on open claims — to the expected losses for an employer of your size and classification. An X-Mod of 1.00 means your losses match expectations. Below 1.00 is a credit (lower premium); above 1.00 is a debit (higher premium).
Eligibility generally kicks in once your policy reaches a certain premium threshold, which means small employers may not yet have an X-Mod. Once you qualify, the factor follows you and can take years to improve after a bad claim year.
This is why prompt reporting, aggressive claims management, and return-to-work programs matter statewide. A well-managed claim that returns an employee to modified duty quickly costs less and moves your X-Mod less.
X-Mods are calculated on a rolling three-year window that excludes the most recent policy year. That means a bad claims year can affect your premium for several cycles. To improve it: invest in workplace safety, report claims immediately, work with your carrier on early return-to-work options, and contest reserve amounts that appear overstated. A single large claim can dominate a small employer's factor, so claim prevention and management are the levers that matter most.
For a quote that accounts for your X-Mod, visit the California Workers' Comp page. For Sacramento-area service, see our Sacramento Workers' Comp page. Call 916-822-9595 — open 365 days a year, 8am to 9pm Pacific, including all major holidays.