We analyse the case where a unit-root test is based on a Dickey-Fuller regression the only deterministic term of which is a fixed intercept. Suppose, however, as could well be the case, that the actual data-generating process includes a broken linear trend. It is shown theoretically, and...

Much research has been devoted to assessing the evidence for linear trend in a time series. We discuss the statistical implications of some recent developments, with specific application to 24 time series of relative primary commodities prices

The Hodrick-Prescott filter is often applied to economic series as part of the study of business cycles. Its properties have most frequently been explored through the development of essentially asymptotic results which are practically relevant only some distance from series endpoints. Our...

In this paper we introduce a new test of the null hypothesis of no cointegration between a pair of time series. For a very simple generating model, our test compares favourably with the Engle-Granger/Dickey-Fuller test and the Johansen trace test. Indeed, shortcomings of the former motivated the...