Estimating Optimal Monetary Policy Rule in Iran based on Hybrid Models

The purpose of this study is to estimate a “hybrid” version of the optimal monetary policy rule in Iran using the optimal control theory. To do this, it is assumed that monetary authorities solve an optimization problem with regard to the constraints of economic structure, which includes five equations of aggregate supply, aggregate demand, exchange rate, demand for money and government expenditure. First, the structural equations’ parameters are estimated using ordinary least squares (OLS) and seemingly unrelated regression (SUR) methods during 1978-2016. Then, the preferences of the monetary authorities for stabilizing inflation and output, and smoothing liquidity growth are chosen with the aim of minimization of social welfare loss. The results indicate that the central bank should consider the deviation of monetary growth rate and the output gap. In addition, the optimal rule of monetary policy derived from the optimal preferences indicates that the central bank must react simultaneously to the changes in inflation, output gap and real exchange rate, in which the role of output gap is of great importance.