What is a Public Policy?

Rule-like statements that specify what groups of people may, must, or must not do in specific circumstances. When fully elaborated, public policies also establish what the penalties (sanctions) are for violating the policy.

A public policy is one that "requires deliberation among a group of people to determine which policy is the best response to a particular problem facing the group".

This definition is taken from Elinor Ostrom, Understanding Institutional Diversity, Princeton University Press, 2005.
The quote is from pp43-44, Diana Hess, Controversy in the Classroom: The Democratic Power of Discussion, Routledge, 2009.