INFERENCE ON SEGMENTED COINTEGRATION
针对实际数据常无法确认协整的问题，提出分段协整概念，即大部分时期存在协整而小部分时期存在非平稳偏差，并研究如何检测和识别短期偏差时期。
A cointegration relation is often interpreted as a long-run equilibrium relation whereas short-run deviations are allowed to a certain extent. In practice, however, real data often fail to confirm cointegration for a well understood economic relation. This paper proposes that in many cases failure of confirming cointegration is due to nonstationary deviations in a relatively small portion of the data period (“short-run”) whereas a cointegration relation prevails in the other periods. We call such a situation segmented cointegration. We study in this paper how to detect segmented cointegration and how to identify the period of short-run deviations.I thank Pentti Saikkonen and three anonymous referees for helpful comments. I am deeply indebted to Peter Phillips for encouragement, discussion, and helpful comments on this work. The research of this paper is supported by the Research Grants Council of Hong Kong (grant HKUST6178/98H) and FRAP B of SUNY-Albany (account 320-9709W).