Objectives. To document the numbers and types of interorganizational partnerships within the national patient safety domain, changes over time in these networks, and their potential for disseminating patient safety knowledge and practices.

Data Sources. Self-reported information gathered from representatives of nationallevel organizations active in promoting patient safety.

Study Design. Social network analysis was used to examine the structure and composition of partnership networks and changes between 2004 and 2006. Data Collection. Two rounds of structured telephone interviews (n 5 35 organizations in 2004 and 55 in 2006).

Principal Findings. Patient safety partnerships expanded between 2004 and 2006. The average number of partnerships per interviewed organization increased 40 percent and activities per reported partnership increased over 50 percent. Partnerships increased in all activity domains, particularly dissemination and tools development. Fragmentation of the overall partnership network decreased and potential for information flow increased. Yet network centralization increased, suggesting vulnerability to partnership failure if key participants disengage.

Conclusions. Growth in partnerships signifies growing strength in the capacity to disseminate and implement patient safety advancements in the U.S. health care system. The centrality of AHRQ in these networks of partnerships bodes well for its leadership role in disseminating information, tools, and practices generated by patient safety research projects.

Key Words. Patient safety, partnership, collaboration, dissemination, network analysis