Projections for enrollment in the new insurance options created under the Affordable Care Act (ACA) are often point-in-time estimates. But just as people frequently move in and out of being uninsured, insurance coverage through Covered California (California’s health insurance marketplace) or through Medi-Cal is dynamic and can change for an individual over the course of a year.

This churn in enrollment is important to understand and predict. In order to maximize the number of insured Californians, Covered California will need to reach individuals who become eligible for coverage between open enrollment periods. Understanding the extent and nature of churn can help in planning for ongoing enrollment, ensuring smooth health coverage transitions and continuity of care, and reducing uninsurance.