RESUMEN
CONTEXT: It is widely hoped that accountable care organizations (ACOs) will improve health care quality and reduce costs by fostering integration among diverse provider groups. But how do implementers actually envision integration, and what will integration mean in terms of managing the many social identities that ACOs bring together? METHODS: Using the lens of the social identity approach, this qualitative study examined how four nascent ACOs engaged with the concept of integration. During multiday site visits, we conducted interviews (114 managers and physicians), observations, and document reviews. FINDINGS: In no case was the ACO interpreted as a new, overarching entity uniting disparate groups; rather, each site offered a unique interpretation that flowed from its existing strategies for social-identity management: An independent practice association preserved members' cherished value of autonomy by emphasizing coordination, not "integration"; a medical group promoted integration within its employed core, but not with affiliates; a hospital, engaging community physicians who mistrusted integrated systems, reimagined integration as an equal partnership; an integrated delivery system advanced its careful journey towards intergroup consensus by presenting the ACO as a cultural, not structural, change. CONCLUSIONS: The ACO appears to be a model flexible enough to work in synchrony with whatever social strategies are most context appropriate, with the potential to promote alignment and functional integration without demanding common identification with a superordinate group. "Soft integration" may be a promising alternative to the vertically integrated model that, though widely assumed to be ideal, has remained unattainable for most organizations.