Investigating the Dynamic Relationship between the Money Growth and Inflation in Iran: An Econophysics Analysis of Quantity Theory of Money

In the current research, using the wavelet method and coherence analysis, it is tried to redefine the relationship between the growth of money (the monetary base and liquidity) and inflation in the economy of Iran. To this end, using the available seasonal data (1982-2017), the coherence of these variables is investigated in different time periods. Unexpectedly, the results indicate that in assessment of the relationship between liquidity and inflation, monetary policies based on liquidity changes has no significant impact on the inflation, but the growth of monetary base in the middle and long term has a direct relationship with inflation and this justifies quantity money theory in Iran more than liquidity variable. Therefore, it seems that, in the long run, the change in liquidity factor is not a suitable strategy for Iran's economy, but in the case of the monetary base, the result is somewhat different and shows in the medium and long term it will have significant impact on monetary policy and inflation. In other words, despite the current study suggests the liquidity variable is endogenous (lag effect) in the short and middle term, but according to available information, one cannot rule out the exogenous hypothesis of the monetary base in the Iranian economy. So, in the long run, on the basis of quantity money theory, money supply (especially monetary base) is still a powerful policy tool owned by the Central Bank of Iran. It is important to note that with regard to special potential of wavelet method in which the simultaneous investigation of short-term and long-term causality is done between time series of variables and the severity of the relationship between them, one cannot consider the inflation as a monetary phenomenon in all periods of times.