PPP Strikes Back: Aggregation And the Real Exchange Rate
证明，由于分类相对价格动态的异质性，传统时间序列和面板方法会严重夸大实际汇率的持续性；在恰当考虑异质性后，实际汇率半衰期大幅降至一年左右，低于罗戈夫三到五年的共识，从而解决了购买力平价谜题。
We show the importance of a dynamic aggregation bias in accounting for the PPP puzzle. We prove that established time series and panel methods substantially exaggerate the persistence of real exchange rates because of heterogeneity in the dynamics of disaggregated relative prices. When heterogeneity is properly taken into account, estimates of the real exchange rate half-life fall dramatically, to little more than one year, or significantly below Rogoffs consensus view of three to five years. We show that corrected estimates are consistent with plausible nominal rigidities, thus, arguably, solving the PPP puzzle.