This document discusses outcomes research, which seeks to understand the end results of healthcare practices and interventions. It describes two agencies, the Agency for Healthcare Research and Quality and the Patient-Centered Outcomes Research Institute, that focus on outcomes research and fund studies to increase healthcare effectiveness. Both agencies emphasize measures like quality of life and patient preferences. The document also discusses positive and negative impacts of outcomes research, how it assesses elements of health important to patients, and how researchers have developed ways to broadly measure health status.