We derive the family of tests for a unit root with maximal power against a point alternative when an arbitrary number of stationary covariates are modeled with the potentially integrated series. We show that very large power gains are available when such covariates are available. We then derive...

Whilst point estimates for mean reversion in real exchange rates suggest reasonable (but long) half lives to shocks, it still remains uncomfortable that models without any mean reversion at all are often compatible with individual country pair data from the floating period. Studies with data...

In situations where theory specifies a potential cointegrating vector amongst integrated variables, it is often required that one test for a unit root in the constructed cointegrating vector. Although it is common to simply employ a univariate test for a unit root for this test, it is known that...

This paper examines the efficiency of the forward yan/dollar market using micro survey data. Conventional tests of unbiasedness do not correspond directly to the zero-profit condition. Instead, we use the survey data to calculate potential profits of individual forecasters based on a natural...

There are a large number of tests for instability or breaks in coefficients in regression models designed for different possible departures from the stable model. We make two contributions to this literature. First, we consider a large class of persistent breaking processes that lead to...