The California Health Interview Survey (CHIS) is the largest state health survey in the nation. It is a random-dial telephone survey that asks questions on a wide range of health topics. CHIS is conducted on a continuous basis allowing it to provide a detailed picture of the health and health care needs of California’s large and diverse population. A full data cycle takes two years to complete, with over 50,000 Californians surveyed. Continuous data collection allows CHIS to generate timely one-year estimates. CHIS is conducted by the UCLA Center for Health Policy Research in collaboration with the California Department of Public Health, and the Department of Health Care Services.