Investigating the Causal Relationship between Producer Price Index and Consumer Price Index for the Economy of Iran

Understanding the nature of the causal relationship among economic variables is crucial for the economic policy-makers and planners. So, this study investigates Granger causality between producer price index (PPI) and consumer price index (CPI) for the economy of Iran. From a policy-making point of view, the findings of the study may inform economic policy-makers in pursuing effective anti-inflationary policies. To this end, monthly data are used over the period 1990- 2011. The results of the cointegration test indicate that there is a long-run equilibrium relationship between these variables. According to Hsiao test, there is bi-directional causality between consumer price index (CPI) and producer price index (PPI) in both short-run and long-run. Toda and Yamamoto test also indicate the bi-directional causal relationship between the variables. However, it seems that causality from PPI to CPI is stronger than that from CPI to PPI, supporting the Cushing and McGarvey (1990) hypothesis.