Corruption, central bank (in)dependence and optimal monetary policy in a simple model

Using a simple macroeconomic model, this paper examines the interaction between corruption and central bank independence in the construction of an optimal monetary policy rule where the instrument of policy is the real interest rate. As such, we are especially interested in how the policy instrument reacts to key macroeconomic variables in the face of possible corruption (modelled here as tax leakage) and possible dependence by the central bank on the fiscal policy process. We analyse this issue by deriving optimal rules for a strict inflation targeting and a real exchange rate target regime. We find that, firstly, the existence of corruption imposes an inflationary bias on the optimal rule – even when the central bank is independent. We find, furthermore, that a central bank that exhibits some dependence exacerbates this effect.