Inappropriate Detrending and Spurious Cointegration

The empirical literature is abundant with detrended cointegration, where cointegration relations are estimated with deterministic trend terms. The use of detrended cointegration will mask important time series properties, however, because trend and cointegration indicate both deterministic and stochastic common trends. Cointegration with and without detrending shows markedly different implications on their long-run relations. A series of Monte Carlo experiments show that inappropriately detrended time series often exhibit cointegration although time series are designed to contain no cointegration. That is, inappropriately detrended time series tend to show spurious cointegration. Foreign exchange rates are analyzed to show the relevance and importance of the inappropriate detrended in cointegration analysis