CPI vs. PPI: Which drives which？

Abstract

The consumer price index (CPI) and producer price index (PPI) are interrelated but significantly different concepts. Relationships between the two indices may be that of causality or non-causality. The paper conducts a Granger-causality test on China’s CPI and PPI data for the period from January 2001 to August 2008, and finds that CPI Granger causes the change in PPI, and the latter reacts to the former with a time lag of 1–3 months. The result may suggest that in contemporary Chinese economy, demand-side factors have played a more important role than supply-side factors, although the two sides both have influences on domestic inflation trend which is measured by CPI.

Keywords

consumer price index (CPI) / producer price index (PPI) / price transmission