Health Disparities
Scaling the health system inequity metric to identify and address healthcare inequities Joanna Dos Santos* Joanna Dos Santos Trillium Health Partners
Background:
Systematic measurement of health inequities is critical for equitable healthcare delivery, yet few standardized approaches exist that are feasible for routine health system use. The Health System Inequity Metric (HSIM), developed at Trillium Health Partners, is a validated approach that quantifies inequities in healthcare utilization and outcomes across socioeconomic gradients using routinely collected administrative data. HSIM is designed to support organizational accountability by embedding equity measurement within standard performance reporting.
Methods:
HSIM applies regression-based modelling to estimate inequities across ordered population groups, generating a single, interpretable metric that reflects the magnitude and direction of disparity. The approach allows comparison across services and over time, while accommodating local population characteristics and data availability. HSIM was applied across health services using linked administrative and area-level sociodemographic data. As an example of applied use, HSIM informed a breast cancer screening initiative, complemented by focus groups with historically underrepresented communities to contextualize identified inequities and inform intervention development.
Results:
HSIM enabled systematic identification of inequities and prioritization of services for equity-focused action. Its standardized yet flexible structure supports meaningful interpretation across diverse service contexts without requiring new primary data collection.
Conclusions:
HSIM provides a scalable, methodologically rigorous approach for translating equity measurement into action. Building on demonstrated success at Trillium Health Partners, HSIM is now being implemented in additional organizations, highlighting its potential to support system-level equity monitoring, intervention planning, and performance improvement across healthcare settings.