More on Ostrom...

Economists have tended to emphasise property rights as a solution to the problem of managing common resources. Typically that involves either privatisation or putting the resource in government hands. But Ms Ostrom, who is a political scientist by training, spent much of her early career studying how communities managed such common resources. She found that groups of people tended to have complex sets of rules, norms and penalties to ensure that such resources were used sustainably. Such self-governance often worked well.

Successful informal institutions, she found, have certain features in common, which sets them apart from institutions that fail. The principles of game theory, particularly the theory of repeated interactions, proved remarkably useful in formulating general principles of how common resources ought to be managed without necessarily resorting to private or state ownership.