Your X-Mod, short for experience modification factor, adjusts your workers’ compensation premium based on your business’s claims experience compared with similar employers. For California business owners, understanding this number can help explain an important part of their insurance costs. [1]
Whether you are preparing for renewal or wondering why your X-Mod changed, a closer look at the numbers can help you identify useful questions and focus your workplace safety efforts.
What does your X-Mod mean
An X-Mod compares your company’s claims experience with the expected experience of businesses in similar industries and of similar size. In California, the Workers’ Compensation Insurance Rating Bureau, or WCIRB, calculates X-Mods for employers that meet the eligibility requirements. [2]
Your X-Mod may appear as a percentage or a decimal factor:
- 100% or 1.00: The comparison point for expected claims experience.
- Below 100% or 1.00: Generally reflects better-than-average claims experience.
- Above 100% or 1.00: Generally reflects worse-than-average claims experience.
A lower X-Mod generally produces a more favorable adjustment to the premium it applies to. However, there is no single “good” X-Mod target for every business, and your rating should be considered alongside your operations and other safety information. [1]
How does your X-Mod affect workers compensation costs
Your X-Mod acts as a multiplier on the premium subject to experience rating. Here is a simplified example:
Premium subject to X-Mod | X-Mod | Premium after X-Mod |
$100,000 | 80% / 0.80 | $80,000 |
$100,000 | 100% / 1.00 | $100,000 |
$100,000 | 120% / 1.20 | $120,000 |
These figures show the X-Mod adjustment alone. Your total premium also depends on payroll, classifications, insurer rates and other applicable adjustments. A lower X-Mod does not automatically mean your total renewal premium will decrease. [2]
How is your California X-Mod calculated
The WCIRB uses payroll, classifications and reported claim information to compare actual losses with expected losses. Claim information includes amounts already paid and reserves for amounts the insurer expects to pay. [3]
The calculation generally involves three policy years within a defined historical experience period. Because the calculation uses older policy data, recent safety improvements may take time to appear in your X-Mod. [4]
California also uses an employer-specific primary threshold that limits how much of each claim enters the actual-loss portion of the calculation, along with other adjustments. As a result, several smaller claims can have a different impact than one larger claim with the same total cost. [5]
Your X-Mod worksheet shows the information used in the calculation. Reviewing it with your insurance agent can help you understand the figures and identify questions about the reported data. [6]
Why did your X-Mod increase
Understanding an increase starts with comparing your current worksheet with the previous one. Items to review include:
- Changes in claim values, including payments and reserves.
- Changes in payroll or the classifications used in the calculation.
- Which policy years entered or left the experience period.
- Updates to the rating values used to calculate expected losses and other formula components.
These factors mean your X-Mod can change even when you have not had a recent injury. Your agent can help you review the worksheet and discuss which changes contributed to the result. [3, 4, 7]
How can you help improve your X-Mod over time
Preventing workplace injuries and maintaining accurate information are practical places to start. Focus on steps your business can take consistently:
- Address recurring injury causes. Look for patterns involving lifting, slips, tools, equipment or particular work areas. Correct the conditions behind repeated incidents.
- Make reporting straightforward. Encourage employees to report injuries and hazards promptly through a clear, reasonable process. Accurate reporting gives you the information needed to respond.
- Follow through on training and inspections. Make sure employees understand safe procedures; supervisors reinforce them and identified hazards are corrected.
- Support a medically appropriate return to work. Coordinate with the claims team and treating provider to identify suitable duties consistent with medical restrictions.
- Review your X-Mod worksheet and claims information. Discuss payroll, classifications and claim details with your agent, and ask about any information that appears inaccurate.
- Start the conversation before renewal. Give yourself time to understand your rating and discuss available carrier safety resources and coverage options.
Keep the focus on preventing injuries and responding effectively. Employees should be able to report injuries without fear of retaliation or pressure to protect a safety score. [8]
Track safety progress between X-Mod updates
Your X-Mod reflects past claims experience. To evaluate current prevention efforts, also track training completion, inspections, near-miss reports and the time it takes to correct hazards. These measures can show whether planned safety actions are actually being completed. [9]
Where applicable, injury rates such as the Total Recordable Incident Rate, or TRIR, provide another point of comparison. Use relevant industry and workforce-size benchmarks, and assess several measures together when reviewing your safety program. [10]
Request a workers comp consultation with Allco
If you have questions about your X-Mod, a recent increase or an upcoming renewal, we at Allco Insurance are here to help. As an independent agency, we can help you understand your workers’ compensation coverage and explore insurance options that fit your business.
Request a Workers’ Comp Consultation
Fill out the form on our workers’ compensation page and mention that you would like a consultation about your X-Mod or coverage. You can also call 714-992-2390 to speak with the Allco team. [11]
Sources
1. WCIRB — Experience Modification Services
2. California Department of Insurance — Workers Compensation
3. WCIRB — Experience Modification
4. WCIRB — Experience Rating Plan effective September 1 2026
5. WCIRB — Experience Rating Formula
6. WCIRB — Experience Rating Form
7. WCIRB — Updated Experience Modification Estimator
8. OSHA — Reporting injuries and illnesses without retaliation
9. OSHA — Program Evaluation and Improvement