Regarding to important role of interest rate in adjusting and performing economic policies, in particular monetary policies, in recent decades too many efforts has been done for adjusting this variable as one of the most important key economic indicators. Due to the noticeable impact of interest rate to solve or generate economic problems in some societies, reducing it to its optimal level is in the first line of agenda as an important issue. In this study, according to Chicago School principles, we determine the most effective economic variables on interest rate. Then we use Bayesian Causal Map (BCM) to analyze the suitable ways of reducing interest rate in Iran over the period of 1976 to 2006. We concluded that interest rate tends to be depress through reducing inflation rate, reducing expected rate of inflation, controlling money stock, controlling credits and reducing budget deficit. Furthemore, the results of study confirm the Chicago School ideas about importance of money and direct and powerful impact of it on real economic variables in Iran and according to beliefs of this school, in process of reducing interest rate, money stock and inflation rate are the most important economic variables in Iran.
JEL Classification: E4, B1, E43, E52, E53