What is RSST?
The Risk Stratification, Segmentation, and Tiering (RSST) algorithm is a key part of Medi-Cal Connect. It provides a consistent, statewide method to identify risk among Medi-Cal members. RSST was designed to make risk stratification more equitable across California.
Unlike most traditional risk prediction models that only flag high-cost or high-need individuals, RSST uniquely identifies members who are not using services they likely need—a sign of hidden or unmet needs for health care and social services. RSST's dual focus on risk and underutilization is essential for surfacing gaps in care that might otherwise remain invisible, supporting proactive and equitable intervention.
RSST groups members into low, medium-rising, or high-risk tiers based on their chances of facing future health, social, or behavioral challenges. This helps ensure care and support are focused where they're needed most. The RSST method is open-source and ensures statewide consistency to help connect high-risk members to services.
RSST includes predictive models for three populations: adult (18+), pediatric (4 months to 17 years); and birthing members. The birthing member population includes any potentially pregnant female member ages 15-49 years, including those who are 12-months postpartum or post-pregnancy loss, as well as infants up to 3 months.
Medi-Cal Connect's RSST is designed to support—not replace—existing health plan tools. It adds a standardized layer of risk information that can enhance current workflows and decision-making, helping to ensure that all Californians have more consistent access to high quality health care
services.
How will RSST be used?
MCPs will be required to use the DHCS RSST algorithm to identify and assess members who are in the high-risk tier. Plans can also use their own tools to identify and serve additional members, but at minimum they must assess all high-risk members flagged by DHCS' RSST approach. This approach ensures consistency in Medi-Cal enrollee assessment and experience across all geographies in the state.
The Population Health Management (PHM) Policy Guide in July 2026 will include additional guidance on when this requirement is effective. Plans will be given at least six months from July to operationalize RSST assessments. DHCS will monitor the impact of the RSST implementation on Medi-Cal members according to the July 2026 RSST policy guidance.
MCPs are encouraged to ingest RSST data and meet with DHCS Medi-Cal Connect staff during the implementation period, which began in July 2025.Taking advantage of this lead time will help ensure a smooth transition and enable plans to gain insights on the use of the RSST and how to maximize benefits for Medi-Cal members.
Learn More
DHCS published several resources to provide a clear, public explanation of how the RSST approach was developed and how it works:
