Online Guide to Workers’ Compensation

Welcome to our comprehensive guide that covers the fundamental aspects of the workers’ compensation system. To understand workers’ compensation insurance and how workers’ compensation insurance policies are written, it’s important to become familiar with the Standard Classification System, experience rating system and regulations concerning business ownership for workers’ compensation insurance purposes.

Team of people laughing at work
Experience Modification Services

Comprehend the role of the WCIRB, what is covered by a workers' compensation insurance policy, how the industry is regulated and where to go for assistance for issues beyond the WCIRB's purview.

Test Audits and Inspections

Discern the difference between Pure Premium Rates and the rates charged by an insurer.

data products icon

Learn how a company's classification impacts its insurance premiums and the basic principles of the classification system, including assignment by analogy, single versus multiple enterprises and general inclusions and exclusions.


Discover the purpose of the experience rating system, eligibility requirements, source of experience rating data and experience modification calculation.

Policyholder Ombudsman

Learn how to determine changes in ownership and what happens to an employer's experience when changes occur.

Woman taking a CompEssentials course on her laptop

While this guide is not a substitute for the knowledge and experience of your insurance professional, it should help you understand the basic workings of the system. Nothing in this guide takes precedence over the Insurance Commissioner's regulations or California law. If you have questions, contact your insurance professional.

California Workers' Compensation Uniform Statistical Reporting Plan—1995

California Workers' Compensation Experience Rating Plan—1995

WCIRB Insurer Codes