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About RSST

Medi-Cal Connect

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?

Beginning January 1, 2027, Medi-Cal managed care plans (MCP) will be required to use DHCS’ standardized RSST risk tiers to prioritize outreach and engagement, guide assessment frequency, inform individualized care planning, and connect members to needed services.

During the implementation period from July 2025 to January 1, 2027, MCPs are required to develop a strategy to fully implement DHCS’ RSST approach within the plan’s Population Health Management (PHM) Program starting January 1, 2027. Each MCP must submit an RSST Implementation Plan (template to be distributed) to DHCS outlining how it will ensure that required infrastructure, resources, technology, and workflows are ready.

Refer to Section D. Understanding Risk Stratification and Segmentation in the July 2026 PHM Policy Guide for detailed guidance. 

Learn More

DHCS published several resources to provide a clear, public explanation of how the RSST approach was developed and how it works: