Risk Shocks
在标准货币动态一般均衡模型中引入金融加速器机制，用美国数据拟合后发现，风险（即横截面异质性不确定性的波动）是驱动商业周期的最重要冲击。
We augment a standard monetary dynamic general equilibrium model to include a Bernanke-Gertler-Gilchrist financial accelerator mechanism. We fit the model to US data, allowing the volatility of cross-sectional idiosyncratic uncertainty to fluctuate over time. We refer to this measure of volatility as risk. We find that fluctuations in risk are the most important shock driving the business cycle.