We consider the impact of a break in the innovation volatility process on ratio-based persistence change tests. We demonstrate that the ratio statistics used do not have pivotal limiting null distributions and that the associated tests display a considerable degree of size distortion with size...

type="main" xml:id="obes12051-abs-0001" <title type="main">Abstract</title> <p>In this article, we investigate the behaviour of a number of methods for estimating the co-integration rank in VAR systems characterized by heteroskedastic innovation processes. In particular, we compare the efficacy of the most widely used...</p>