CWCI Finds CT Claims’ Share of California Workers’ Comp Nearly Doubled from 2018-2025
The share of California’s workers’ compensation claims identified as cumulative traumas (CT) nearly doubled between 2018 and 2025, with the sharpest growth occurring after 2021, according to a new California Workers’ Compensation Institute (CWCI) study. The study found that the increase was widespread, extending beyond regions and industries that historically accounted for the largest share of CT claims, but traditional factors such as population and employment growth, overall claim volume and changes in worker tenure explain relatively little of the increase, raising questions about what is driving the continued growth of CT claims.
The study uses data from CWCI’s Industry Research Information System (IRIS) to examine CT claim trends statewide and evaluate factors that may help explain the increase. It found that CT claims rose from about 1 in 11 California workers’ compensation claims in 2018 to 1 in 6 in 2025, with most of the increase coming after the first two years of the COVID-19 pandemic. Other key findings from the study include:
Growth was widespread. CT rates increased across every region, industry, body-part category and worker-tenure group examined. Los Angeles continued to have the highest CT rate, but some of the largest increases were in regions where CT claims historically were less common, including the Bay Area and Central Valley.
