Non-Informative Tests of the Unbiased Forward Exchange Rate
指出外汇文献中常用的远期汇率无偏性检验存在联立性偏误，导致检验结果不可靠，而协整检验则通常不拒绝无偏性假设。
This paper reexamines a familiar but unsettling result in the foreign exchange literature: that the forward rate is not an unbiased predictor of the future spot rate. The paper outlines why some frequently used tests of unbiasedness are non-informative in the sense that they are incapable of correctly testing the hypothesis. Specifically, many of these tests are based on regressions that suffer from simultaneity bias, resulting in biased and inconsistent estimators. This is true whether the tests are conducted using stationary or non-stationary data. We demonstrate this point both analytically and with simulations. Tests of co-integration, which are not subject to the critique presented in the paper, generally fail to reject unbiasedness.