This paper suggests that the relevant question concerning unit root' in the U.S. real GNP time series pertains to the relative importance of difference-stationary and trend-stationary components. Vari
This paper proposes a class of procedures that consistently classify the stochastic component of a time series as being integrated either of order zero (l(0 or one (l(1 for general 1(0) and 1(1) proce
We use the revised estimates of U.S. GNP constructed by Christina Romer (1989) to assess the time-series properties of U.S. output per capita over the past century. We reject at conventional significa
