Empirical test of purchasing power parity using a time-varying cointegration model for China and the UK

Abstract

This study revisits purchasing power parity (PPP) for China and the United Kingdom (UK) by applying a time-varying cointegration model. When traditional linear unit root tests and a time-invariant cointegration test are performed, we find fixed long-run equilibrium in China and the UK. However, we cannot check the movement of the cointegration vector. To solve this limitation, we perform a time-varying cointegration. The result of a time-varying cointegration model shows that the validity of PPP for China varies over time. On the other hand, PPP does not hold for all periods for the UK. This study shows that the effect of government policy varies depending on the degree of openness. In China with a low degree of openness, export-oriented policies have had a positive impact on PPP. However, in the UK with a high degree of openness, PPP was not valid due to the role of the exchange rate as an asset price and the downward rigidity of wage.