“When local users of a forest have a long-term perspective, they are more likely to monitor each other’s use of the land, developing rules for behavior,” Ms. Ostrom said in an interview. “It is an area that standard market theory does not touch.” Often working with her husband, Vincent, 90, who is a professor emeritus at Indiana, Ms. Ostrom concluded in her research that the “tragedy of the commons” was an inaccurate concept. Particularly in 17th- and 18th-century England and Scotland, the concept described villagers’ overgrazing of their herds on the village commons, thereby destroying it as pasture. The solution often invoked was to convert the commons to private property, on the ground that self-interested owners would protect their pasture land. “Conservatives used the tragedy of the commons to argue for property rights, and efficiency was achieved as people were thrown off the commons,” said Joseph E. Stiglitz of Columbia University, a Nobel laureate in economics himself. “But the effects of throwing a lot of people out of their livelihood were enormous. What Ostrom has demonstrated is the existence of social control mechanisms that regulate the use of commons without having to resort to property rights.”