Monetary Policy, Taylor's Rule and Instability

We analyse the dynamic behaviour of an economy where the central bank (CB) sets interest rates according to a Taylor-type policy rule. A simple model for a closed and instability-prone economy is constructed and subjected to formal dynamical analysis and numerical simulation. It is shown that a requirement for local stability is that the two response coefficients in the policy rule be positive. Similarly, it is shown that raising the response coefficient of the output gap increases the likeliness of the economy being stable, whereas raising the response coefficient of the inflation gap has an uncertain and probably negligible effect on local stability. Self-sustained oscillations may arise for certain parameter values. Policy mistakes in the estimation of the long-run equilibrium real interest rate or potential real GDP may prevent the CB from achieving its inflation target. A suggestion for enhancing the stabilization capacity of Taylor-type policy rules in the context of the model presented is made