To date the literature on quantile regression and least absolute deviation regression has assumed either explicitly or implicitly that the conditional quantile regression model is correctly specified. When the model is misspecified, confidence intervals and hypothesis tests based on the...

We present the asymptotic properties of double-stage quantile regression estimators with random regressors, where the first stage is based on quantile regressions with the same quantile as in the second stage, which ensures robustness of the estimation procedure. We derive invariance properties...

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

Although the t-ratio variant of the Dickey-Fuller test is the most commonly applied unit root test in practical applications, it has been known for some time that readily implementable, more powerful modifications are available. We explore the large sample properties of five of these modified...

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 consider the situation where the deterministic components of the processes generating individual series are linear trends and the individual series are independent I(0) or I(1) processes. We show that when those time series are used in ordinary least square regression, the...

Although the t-ratio variant of the Dickey-Fuller test is the most commonly applied unit-root test in practical applications, it has been known for some time that readily implementable, more powerful modifications are available. We explore the large-sample properties of five of these modified...

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...

Assume that a time series is generated by an autoregression which has atmost one unit root. A correctly specified model, including linear time trend, is estimated by ordinary least squares, but no allowance is made for any unit root in the generating process. We investigate the impact of...

Sharpe style regression has become a widespread analytic tool in the financial community. The style regression allows one to investigate such interesting issues as style composition, style sensitivity, and style change over time. All previous methods to obtain the distribution and confidence...