The authors examined the impact of Senate Bill (SB) 1160 on utilization review (UR) processes and medical treatment in California’s workers’ compensation system. SB 1160 reduced UR requirements for some treatments during the first 30 days after a work-related injury for injuries occurring on or after January 1, 2018, with the goals of reducing administrative burden on providers and improving the timeliness and quality of care for injured workers.

Examining the Impact of Senate Bill 1160 on Utilization Review and Medical Treatment in California Workers' Compensation

Stephanie Rennane, Sara E. Heins, Danya Birnbaum, Matthew B. Forbes, Travis Hubble, Michael Dworsky

ResearchPublished Jul 20, 2026

The authors examined the impact of Senate Bill (SB) 1160 on utilization review (UR) processes and medical treatment in California’s workers’ compensation system. SB 1160 reduced prospective UR requirements for some treatments during the first 30 days following a work-related injury for injuries occurring on or after January 1, 2018, with the goals of reducing administrative burden on providers and improving the timeliness and quality of care for injured workers. Drawing on data from (1) two large claims administrators, (2) the California Workers’ Compensation Information System, and (3) the Independent Medical Review database, the authors assessed whether the law achieved its goals by analyzing UR approval and denial rates, patterns in receipt of guideline-concordant medical care, and time to treatment before and after the law’s implementation. The findings and policy recommendations are intended to inform ongoing efforts by the California Department of Industrial Relations (DIR) and the broader workers’ compensation community to refine and improve UR policy.

Key Takeaways

UR approval rates in the sample consistently exceeded 90 percent during the first 30 days after injury both before and after SB 1160

  • Approval rates for requests for authorization submitted during the first 30 days after injury exceeded 90 percent across nearly all treatment categories.

Guideline-concordant physical therapy (PT) increased during the first 30 days after injury after SB 1160 implementation

  • Among injured workers with diagnoses for which PT is recommended, the odds of receiving PT within 30 days were 13 percent higher in the post-implementation period.
  • There was also a reduction in time to the first PT visit in the first 30 days, from an average of 13.4 days prior to SB 1160 to 11.9 days in the post–SB 1160 period.

SB 1160 was associated with small changes in other guideline-concordant and guideline-discordant care

  • The odds of receiving guideline-concordant braces or immobilizers increased by 8 percent, but time to first treatment did not change significantly.
  • The odds of receiving acupuncture among injured workers for whom it is not recommended were significantly higher after SB 1160. However, overall rates of guideline-discordant acupuncture remained low throughout the study period.
  • Although magnetic resonance imaging (MRI) is explicitly excluded from SB 1160’s provisions, there was a small but statistically significant decline in MRI use in the first 30 days after injury following SB 1160.
  • The modest effect sizes across all treatment types likely reflects that common early treatments were already being approved and delivered in a timely manner before the law’s implementation.

Recommendations

  • DIR should ensure that claims administrators comply with requirements to publicly post their UR plans and systematically document variation in prior authorization practices across claims administrators to inform future standardization efforts.
  • The legislature should consider expanding reduced UR requirements to additional guideline-concordant treatment types and beyond the 30-day window, although such expansions should be pursued carefully and informed by further analysis of treatment outcomes and existing prior authorization practices.
  • DIR should leverage its ongoing development of a systemwide UR database to establish standardized data collection requirements, prioritizing fields from the request for authorization form and including claim and provider identifiers to enable linkage with other data systems and support analysis of UR’s impact on care quality and timeliness.

Topics

Document Details

  • Copyright: State of California Department of Industrial Relations
  • Publisher: RAND Corporation
  • Availability: Web-Only
  • Year: 2026
  • Pages: 100
  • DOI: https://doi.org/10.7249/RRA4256-1
  • Document Number: RR-A4256-1

Citation

Chicago Manual of Style

Rennane, Stephanie, Sara E. Heins, Danya Birnbaum, Matthew B. Forbes, Travis Hubble, and Michael Dworsky, Examining the Impact of Senate Bill 1160 on Utilization Review and Medical Treatment in California Workers' Compensation. Santa Monica, CA: RAND Corporation, 2026. https://www.rand.org/pubs/research_reports/RRA4256-1.html.
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This research was sponsored by the California Department of Industrial Relations and conducted in the Financing and Organization Program of RAND Health.

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