HEDIS, or Healthcare Effectiveness Data and Information Set, is a widely used set of performance measures in the managed care industry. It involves a comprehensive set of standardized measures designed to assess the quality of healthcare services delivered by health plans. HEDIS measures cover various aspects of healthcare performance, including preventive care, chronic disease management, patient safety, and member satisfaction. Health plans and providers use HEDIS data to evaluate and compare their performance against industry benchmarks, identify areas for improvement, and drive quality improvement initiatives. HEDIS data also informs consumers, employers, and regulatory bodies about the quality of healthcare services provided by different health plans, contributing to transparency and accountability in the healthcare system.