The Agency for Healthcare Research and Quality (AHRQ) defines a primary care practice-based research network (PBRN) as a group of practices devoted principally to the primary care of patients and affiliated with each other (and often with an academic or professional organization as well) to investigate questions related to community-based practice and to improve the quality of primary care. This definition includes the sense of an ongoing commitment to network activities and an organizational structure that transcends a single project.
It has been said that if you have seen one PBRN, you have seen one PBRN. This is because each is unique with regard to its mission, vision, purpose, and structure. Not all are based in primary care settings. Some are local, while others are regional; some are discipline-specific (e.g., family practice, dental), while others are geographically centered or serve various populations (e.g., underserved populations). A PBRN is a group of practices consisting of academic and community-based practices (either or both) devoted principally to the care of patients. PBRNs are often affiliated with each other (i.e., meta-networks), and frequently, they are affiliated with academic or professional organizations as well.