Their model reduces the sources of all recessions to just six shocks – “oil, monetary policy, productivity, uncertainty, liquidity/financial risk, and fiscal policy” – and explains most of the post-2007 downturn in terms of just two of these factors: “uncertainty” and “liquidity/financial risk.” But, even if we accept that conclusion, we are left to wonder what caused large shocks to “uncertainty” and to “liquidity/financial risk” in recent years, and how reliably such shocks can be predicted.
他们的模型将所有衰退的成因缩减为只有6大冲击——“石油、货币政策、生产力、不确定事件，流动性/金融风险和财政政策”——并将2007年前的大多数经济衰退仅仅归因为其中两个因素：“不确定事件”和“流动性/金融风险”。但即便我们接受了这个结论，但依然要思考究竟是什么导致了近几年的“不确定事件”和“流动性/金融风险”，以及如何有效地预测这些冲击。