Time Inconsistency

Monetary policy rule is an approach to avoid time inconsistency problem as regarded by new classical economist to choose a time plan for policy making in order to maximize households€™ well-being. The foundation of time inconsistency problem is not coincidence of expectations as an ex-ante variable, which is expected variable, with actual variable as an ex-post variable. Expectations in Finn Kydland and Edward Prescott as the 2004 laureates of the Nobel Memorial Prize in Economics, is rational and formed only by a representative agent because of the discretionary policy of benevolent planner. However the benevolent planner may be as an international planner. In this paper, we develop the model of Kydland and Prescott, by substituting the assumption of heterogeneous households (a domestic household and foreign household) instead of a representative agent and using heterogeneous beliefs. The recent assumption helps us to have an alternative time inconsistency equilibrium with at least two different sources of expectations, which is called Dichotomy Sources of Expectations (DSE) as the main contribution of this paper .We then use expectations-adjusted Phillips curve to see the conditions of time inconsistency of k percent monetary rule of Friedman in a framework of DSE €™s Model . The results show that expectations-adjusted Phillips curve in a society with DSE is not vertical and Friedman's k-percent rule may not be optimal. We find out that, not only an international benevolent planner but also a foreign household must set a rule to maximize the well-being of the world. Indeed, we need a multi-dimensional rule for any international monetary policy.   JEL Classification: D83, D81, D84, E52, E63