The United States is moving toward greater transparency and value in health care, yet little is known about the impact public reporting has had on quality. The Wisconsin Collaborative for Healthcare Quality is a leader in this area—publicly reporting comparative measures of health care quality, sharing and refining best practices, and encouraging organizations in the state to agree on benchmark measures. The collaborative, which has reported performance data for five years, provides a unique opportunity to assess how public reporting affects health outcomes and quality of care. As part of this evaluation, the project team will assess changes in ambulatory care measures in Wisconsin, as well as changes in health care utilization and costs. The team will also survey health care providers to gather information on clinical interventions targeting specific medical conditions.