The Division of Workers’ Compensation (DWC) announced August 19, 2026 that it has posted a new RAND Corporation report examining whether Senate Bill 1160 (2016) succeeded at its two original goals: reducing administrative burden on medical providers and speeding up timely, appropriate care for injured workers in the first 30 days after a work injury. The underlying RAND study, conducted by researchers Stephanie Rennane, Sara Heins, Danya Birnbaum, Matthew Forbes, Travis Hubble, and Michael Dworsky under a DIR-funded contract reportedly worth around $300,000, is the first empirical evaluation of the law since it took effect for injuries on or after January 1, 2018.

SB 1160 eliminated prospective utilization review (UR) for select treatments delivered in the first 30 days after a compensable injury — common early-stage care like physical therapy and initial X-rays — so long as the treatment was consistent with the Medical Treatment Utilization Schedule (MTUS) and delivered within an employer’s medical provider network. The law left several categories explicitly subject to prospective UR even within that first month: surgery, pharmaceuticals, imaging other than X-rays, psychological treatment, home health care, and a short list of other services the DWC has since designated by regulation, including several types of spinal injections.

To evaluate the law, RAND combined four data sources spanning January 2017 through January 2024 (one year before SB 1160 and six years after): individual-level treatment-authorization records from two large, unnamed claims administrators covering Northern and Southern California; audit data DIR’s Audit and Enforcement Unit compiles from randomly sampled authorization requests statewide; the state’s Independent Medical Review database, covering 276,119 disputed UR decisions; and medical billing data from the California Workers’ Compensation Information System, which the team mapped against 195 clinical practice guidelines to classify treatment as guideline-concordant or guideline-discordant. Both DIR’s release and RAND’s own executive summary frame the study around the same three questions: Did UR approval rates for early treatment requests change after SB 1160? Did injured workers become more likely to receive guideline-concordant care? Did they receive that care faster?

UR approval rates for treatment requested in the first 30 days after injury “consistently exceeded 90 percent both before and after SB 1160 took effect, with no statistically significant change.” That held true across nearly every treatment category studied, including physical therapy, pharmacy, imaging, consultations, surgery, durable medical equipment, occupational therapy, acupuncture, chiropractic care, immobilizers, and X-rays, in data from at least one of the two claims administrators. RAND attributes the flat approval rates to the same underlying cause: widespread “prior authorization” programs that let providers deliver routine early treatment without ever filing a formal authorization request at all. RAND’s review of 15 publicly posted UR plans found 13 already had such a program, frequently covering the exact treatments SB 1160 targeted, which is the report’s central explanation for why the law’s measured effect on approval rates was so small — for many claims administrators, there was little UR friction left to remove by 2018.

Where the law did move the needle was physical therapy specifically. DIR’s release states that among injured workers with diagnoses for which PT is recommended, “the odds of receiving physical therapy within 30 days were 13 percent higher following the implementation of SB 1160,” and that the average wait for a first PT visit fell from 13.4 days to 11.9 days — figures pulled directly from RAND’s findings. RAND’s fuller report adds that guideline-concordant use of braces and immobilizers rose more modestly (8% higher odds of receipt within 30 days, with no significant change in timing), and that guideline-concordant X-ray receipt showed no significant change at all, which the researchers attribute to X-rays already being commonly pre-authorized before the law.

RAND found a small but statistically significant increase in guideline-discordant acupuncture — acupuncture given for conditions where it isn’t recommended during the acute phase with the odds of receiving it 24% higher after SB 1160, though the overall rate remained low (under 3% of relevant cases throughout the study) and showed no corresponding drop in time-to-treatment, leading the researchers to call its practical significance limited. RAND also documented a small decline in MRI use (7% lower odds) after the law took effect, despite MRI being explicitly excluded from SB 1160’s reduced-review provisions and therefore not something the law should have directly affected; the researchers attribute this to unrelated secular trends, pre-existing changes at individual claims administrators, or COVID-19-era disruption rather than to the law itself, and use it as a caution against reading any post-2018 change as automatically caused by SB 1160.

RAND’s analysis found that the treatment categories excluded from SB 1160 — particularly imaging and psychiatric or psychological services — have substantially lower approval rates than the categories the law already covers, and that most UR activity and denials occur after the 30-day window SB 1160 addresses, not within it. On that basis, RAND recommends DIR: (1) systematically document and standardize the informal prior-authorization exemptions that vary widely across claims administrators; (2) examine whether streamlined UR treatment should extend beyond the first 30 days or be targeted by treatment type and strength of clinical evidence, rather than tied to a fixed time window, since that may better match where UR actually constrains care; and (3) invest in standardized, systemwide UR data infrastructure, since the researchers found no comprehensive database of UR decisions existed and had to reconcile incompatible formats from just two cooperating claims administrators to conduct the study at all.