This paper proposes unit root tests based on partially adaptive estimation. The proposed tests provide an intermediate class of inference procedures that are more efficient than the traditional OLS-based methods and simpler than unit root tests based on fully adaptive estimation using...

In this paper, starting from continuous-time local level unobserved components models for stock and flow data we derive locally best invariant (LBI) stationarity tests for data available at potentially irregularly spaced points in time. We demonstrate that the form of the LBI test differs...

This paper considers the economic implications of having unit roots in stochastic processes of variables like consumption or GDP. Using a variety of models, we develop indirect tests for unit roots based on sharp distinctions that should arise when the scale variable is either difference...

This paper studies the asymptotic properties of a nonstationary partially linear regression model. In particular, we allow for covariates to enter the unit root (or near unit root) model in a nonparametric fashion, so that our model is an extension of the semiparametric model analyzed in...

This paper provides a theoretical functional representation of the density function related to the Dickey- Fuller random variable. The approach is extended to cover the multivariate case in two special frameworks: the independence and the perfect correlation of the series.

Many economic and financial time series show evidence of trending behavior or non stationarity in the mean. An important econometric goal is determining the most proper form of the trend in the data. The transformations of series depend on whether the series is trend stationary or difference...

This study examines the sustainability of trade deficit with allowance of structural breaks and seasonal adjustments as both variables have been subject to structural changes and affected by seasons. We find that, in all the cases, there is long run relationship between export and import. This...

In this paper, we study the size distortions of the KPSS test for stationarity when serial correlation is present and samples are small and medium-sized. It is argued that two distinct sources of the size distortions can be identified. The first source is the finite-sample distribution of the...

The standard conclusion that is drawn from this empirical evidence is that many or most aggregate economic time series contain a unit root. However, it is important to note that in this empirical work the unit root is set up as the null hypothesis testing is carried out ensures that the null...

In this paper, the long-run relationship between Sri Lankan exports and imports during the period 1950 to 2006 is examined using unit root tests and cointegration techniques that allow for an endogenously determined structural break. The results failed to support the existence of a long-run...