CPI与PPI持续性“背离”的结构性解释

A Structural Explanation for the Divergence Between CPI and PPI

本文基于新凯恩斯框架考察三种外生冲击对CPI和PPI的影响,并尝试对CPI与PPI"背离"进行解释。研究发现:(1)货币政策冲击对CPI、PPI的影响存在非对称性,央行货币调控时应更加关注利率调整对PPI的影响;(2)短期内需求冲击更易引致价格波动,且对CPI影响大于PPI;长期内供给冲击对价格波动影响强于需求冲击,且对PPI影响大于CPI。同时,本文发现财政因素也是导致CPI与PPI"背离"的原因。本文认为当前政府短期可通过完善需求管理抑制CPI与PPI"背离"程度扩大,长期应坚持供给侧改革以扭转二者"背离"趋势,以此健全新常态下价格调控体系并促进经济行稳致远。

Based on the new Keynesian framework, this paper analyzes the impacts of three exogenous shocks on CPI and PPI, and attempts to explain the long-term departure between CPI and PPI. The paper demonstrates two major conclusions. Firstly, the impacts of monetary policy on CPI and PPI are asymmetry, so the central bank should pay more attention to the im- pacts of interest rate adjustment on PPI. Secondly, demand shocks are more likely to cause price fluctuations than supply shocks in short-term, and the impact of demand shocks on CPI is greater than that of PPI ; the impact of supply shocks on price volatility is stronger than demand shocks in long-term, and PPI is more sensitive to supply shocks than CPI. At the same time, the article also finds that fiscal factors also lead to the recent departure of CPI and PPI. The paper argues that the government should shorten the deviation extent of CPI and PPI by improving the demand management in the short term, and turn back the long-term deviation trend by the supply-side structural reform so as to improve the price regulation system and maintain sus- tainable economic growth.