The purpose of this paper is to derive the asymptotic distributions of some Lagrange Multiplier (LM) tests for unit roots in time series models in the presence of missing observations, and to provide evidence on the small sample properties of these tests. LM tests for a unit root in a...

We discuss some challenges presented by trending data in time series econometrics. To the empirical economist there is little guidance from theory about the source of trend behavior and even less guidance about practical formulations. Moreover, recent proximity theorems [W. Ploberger, P.C.B....