Measuring the Effect of the Zero Lower Bound on Medium- and Longer-Term Interest Rates
提出一种方法测量零下限对不同期限国债收益率的影响，发现2008-2010年1-2年期收益率并未受明显约束，货币政策与财政政策效果与往常相当，直到2011年底才出现更明显的约束。
According to standard macroeconomic models, the zero lower bound greatly reduces the effectiveness of monetary policy and increases the efficacy of fiscal policy. However, private-sector decisions depend on the entire path of expected future short-term interest rates, not just the current short-term rate. Put differently, longer-term yields matter. We show how to measure the zero bound's effects on yields of any maturity. Indeed, 1- and 2-year Treasury yields were surprisingly unconstrained throughout 2008 to 2010, suggesting that monetary and fiscal policy were about as effective as usual during this period. Only beginning in late 2011 did these yields become more constrained.