通胀—增长权衡和中国菲利普斯曲线的平坦化

近年来发达经济体出现了菲利普斯曲线平坦化现象,但有关中国的研究尚缺乏共识。本文基于实证和理论分析,系统研究了中国菲利普斯曲线的平坦化问题。首先,结合货币政策冲击和月度SVAR框架,发现通胀的响应程度在2010年后大幅下降。由于证据显示总需求曲线并未平坦化,因此通胀响应弱化可解读为菲利普斯曲线的平坦化。数据显示,菲利普斯曲线平坦化与生产率增长放缓同时发生,因此,本文在标准DSGE模型中引入纵向内生增长渠道,该渠道基于研发投入和知识资本积累,从而使生产率内生于经济周期。研究发现:(1)内生增长渠道放大了需求冲击对产出的影响,但缩小了需求冲击对通胀的影响;(2)内生增长渠道改变通胀和增长之间的替代关系,但不改变边际成本向通胀的传导。分段估计显示,2010年后,通胀和增长的关系弱化是边际成本传导变弱和内生增长渠道变强共同作用的结果。本文认为,由于菲利普斯曲线的平坦化,中央银行应继续坚持稳增长和就业优先战略,关注但不必过于担心由此引发的通胀压力。

The Inflation-Growth Trade-off and the Flattening of the Phillips Curve in China

Stabilizing growth has become a keyword in China's economy. Inflation and growth are the two primary macroeconomic objectives. According to classical macroeconomic theory, there is a trade-off between inflation and growth, at least in the short run, which is represented by the Phillips curve. The ability of central banks to control inflation depends on the strength of this trade-off. However, since the 1990s, there have been signs of a disconnect between inflation and growth in developed economies. One popular explanation for this disconnect is that the Phillips curves of these economies have flattened. This has led to an intense academic debate on whether and why the Phillips curves have flattened. Most studies show that the Phillips curves in developed economies have indeed flattened. However, a few economists disagree. Some studies explore whether China's Phillips curve has also flattened, with mixed results. This study makes the following contributions.First, most studies use partial equilibrium models to directly estimate various Phillips curves for China. However, this approach may suffer from varying degrees of misspecification and lack robustness. We indirectly analyze the trade-off between inflation and growth using demand shocks and a heteroskedastic monthly structural vector autoregressive model. The results show that inflation and output increase with a one-unit monetary policy shock. The inflation-relative response weakens substantially after 2010, with a significant decrease in the Phillips multiplier. In the robustness tests, the effect of economic policy uncertainty shocks on inflation likewise weakens substantially after 2010, and the primary findings hold in the factor model. Next, we exclude the possibility of a flat aggregate demand curve and find that the central bank's anti-inflationary awareness does not increase after 2010. Thus, the weakening inflation response can be interpreted as a flattening of the Phillips curve.Second, considering that the period during which the Phillips curve flattens corresponds to a general slowdown in the Chinese economy, we argue that the two phenomena are compatible. We introduce knowledge capital accumulation and endogenous total factor productivity into the standard dynamic stochastic general equilibrium model. The results show that monetary policy and physical capital investment shocks are the main factors affecting inflation. The endogenous growth channel amplifies the effect of demand shocks on the output variables but weakens the effect on marginal costs and inflation. The endogenous growth channel negatively affects productivity, weakening the isokinetic relationship between inflation and output growth. The subsample estimation results show that the generalized Phillips curve flattens significantly after 2010 due to the combined effect of the endogenous growth channel and a weak marginal cost pass-through.Our findings have broad implications for macroeconomic regulation and control in China. First, from a monetary policy perspective, the flattening of the Phillips curve eventually leads to a flattening of the aggregate supply curve, which implies that demand shocks play a prominent role and may dominate the economic cycle; therefore, it is beneficial for the central bank to take a Keynesian approach. If growth changes more than inflation, the central bank's objective function should empower growth and employment rather than strictly targeting inflation. A flat Phillips curve also implies a reduction in the central bank's ability to stabilize inflation, or a higher “sacrifice rate.” Ceteris paribus, greater changes in employment and output growth are needed to bring real inflation back on target. Second, from an endogenous growth perspective, more attention should be paid to “cross-cyclical adjustment.” To cope with the complex domestic and external economic environment, the government should make cross-cyclical adjustments and maintain policy continuity and stability. Due to the weakening relationship between inflation and output growth and the medium-to long-term nature of productivity evolution, policymakers should focus on the long-term dynamic equilibrium between growth stabilization and risk prevention, gradually moving away from smoothing out short-term fluctuations to providing medium-to long-term precautionary support. Third, from an inflationary perspective, although upside risks to global inflation remain, the central bank's Monetary Policy Implementation Report points out that China's inflation is largely manageable. Indeed, China's money supply has always matched its economic growth. Moreover, expanding the scope of demand-side policies may positively affect supply and productivity, thereby reducing the inflationary pressure on the economy.