The problem of time inconsistency arises from two different sources. First, as shown by Guillermo A. Calvo (1978), the re is an incentive for each government to engage in an initial unanti cipated inflation. Second, as discussed by Robert E. Lucas and Nancy L. Stokey (1983), there is an...

This paper considers a class of statistics that can be written as the ratio of the sample variance of a filtered time series to the sample variance of the original series. Any such statistic is shown to be optimal under normality for testing a null of white noise against some class of serially...