Should exchange rate regime classifications be based purely on some measure of exchange rate flexibility, or should such flexibility be judged in proportion to the degree of exchange market pressure (EMP), as reflected in the behaviour of international reserves? Some authors have claimed that the best approach to classifying exchange rate regimes is to estimate to what extent EMP is absorbed in reserve variability rather than exchange rate variability. Empirical evidence is presented on the variability of reserves and exchange rates for 193 countries from 1980 to 2019. Pegged regimes do not display any more reserve volatility than floats. In most regimes there is a small but statistically significant positive correlation between reserve accumulation and exchange rate appreciation in monthly data, but this effect is no stronger in less flexible regimes, where intervention is expected to be greater. A flexibility index is constructed, based on the ratio of exchange rate flexibility to reserve volatility, and is compared to one based solely on exchange rate flexibility by investigating its conformity with the IMF de facto classification. The flexibility index that takes reserves into account does not improve the identification of pegs, but it helps to a limited extent to distinguish free floats from managed floats.

汇率制度分类应该纯粹基于某种程度的汇率灵活性衡量标准，还是应该根据反映在国际储备行为中的汇率市场压力（EMP）的程度来判断这种灵活性？一些作者声称，对汇率制度进行分类的最佳方法是估计EMP在多大程度上吸收了储备波动而不是汇率波动。经验证据表明，1980年至2019年间193个国家的外汇储备和汇率具有可变性。钉住汇率制度的外汇储备波动性没有浮动多。在大多数情况下，月度数据中的储备积累和汇率升值之间存在很小但具有统计学意义的正相关关系，但是在灵活性较差的方案中这种效果不会更强，预计干预将会更大。基于汇率灵活性与储备波动率之比，可以构建一种灵活性指数，并通过调查其与IMF实际分类的一致性，将其与仅基于汇率灵活性的指数进行比较。考虑到准备金的灵活性指数并不能改善对钉子的识别，但是在一定程度上有助于区分自由流通量和托管流通量。