Abstract   Currently dominant ideas about the social accountability of museums demand that museums produce “intended outcomes”: positive changes to visitors. Proponents commonly depict this process as a “logic model,” a tightly controlled sequence of events that moves from goal to intended outcome. A tightly coupled system obliges all elements to work toward a common goal. But studies in a variety of fields have shown that tightly coupled systems are achievable only under specific environmental conditions, which are not met within the network of relationships in which museums work. Instead, this article views the museum and its relationships as a loosely coupled system. Each element has its own purposes, and strives to maintain its own autonomy. Interests overlap, but are not identical. In the loosely coupled system, encounters generate a wide and unpredictable range of events. This approach offers advantages for the long-term sustainability of museums.