Purchasing Power Parity in the Long Run
用更有效的估计方法重新检验长期购买力平价，发现实际汇率并非随机游走，短期偏离约三年减半，对汇率研究者有参考价值。
This paper re-examines the evidence on Purchasing Power Parity (PPP) in the long run. Previous studies have generally been unable to reject the hypothesis that the real exchange rate follows a random walk. If true, this implies that PPP does not hold. In contrast, this paper casts serious doubt on this random walk hypothesis. The results follow from more powerful estimation techniques, applied in a multilateral framework. Deviations from PPP, while substantial in the short run, appear to take about three years to be reduced in half.