The theory of economic policy has its roots in the contributions of Tinbergen and Theil, who solved the problem of a policymaker aiming to achieve certain values for his policy targets, or to minimize a loss function defined on those targets, by using the available policy instruments. After...

Rational expectations are often used as a strong argument against policy activism, as they may undermine or neutralize the policymaker’s actions. Although this sometimes happens, rational expectations do not always imply policy invariance or ineffectiveness. In fact, in certain circumstances...