Another problem with using the five-year, five-year-forward rate of expected inflation to gauge QE’s effectiveness is that the rate is correlated with oil prices. Indeed, when oil prices fell last year, so did inflation expectations (measured however imperfectly).
使用五年后的五年期预期通胀率作为量化宽松效果指标的另一个问题是这一通胀率与油价相关。事实上，当去年石油价格下跌时，通胀预期也下降（不管其测量多么不完美）。欧洲央行宣布量化宽松恰逢油价反弹，而这在某种程度上将提高通胀预期。