NO.PZ2018091706000057
问题如下：
If the emerging market country used capital controls
instead, this approach would:
选项：
A.lead to a less
independent monetary policy
be more likely to
succeed when capital flows are less persistent
require that the
ratio of foreign exchange reserves to FX market turnover be high
解释：
Although
the empirical evidence is mixed, to a large extent the relativesuccess of
capital controls depends on the magnitude and persistence of the capitalinflows
that the policymakers are trying to resist (the less persistent, the higher
theeffectiveness). A successful capital control policy tends to increase, not
decrease,monetary policy independence. As a regulatory measure, capital
controls do not dependdirectly on the level of foreign exchange reserves.
解析：尽管经验证据好坏参半，但在很大程度上，资本管控的有效力取决于政策制定者试图抵御的资本流入的规模和持续性(持续性越弱，有效性越高)。所以B选项正确。
一个成功的资本管控政策倾向于增加而不是减少货币政策的独立性。所以A选项错误。
作为一项监管措施，资本管制并不直接取决于外汇储备水平。所以C选项错误。
请问能否对解析里说的“持续性越弱，有效性越高”再进一步解释一下吗？
