This paper analyzes the dynamics of the Spanish public debt-GDP ratio during the period 1850-2021. We use recent procedures to test for explosive bubbles under the presence of time-varying volatility (Harvey, Leybourne, Sollis and Taylor, 2016; Harvey, Leybourne and Zu, 2019, 2020; Kurozumi, Skorobotov...

This paper analyzes the dynamics of the Spanish public debt-GDP ratio during the period 1850-2021. We use recent procedures to test for explosive bubbles under the presence of time-varying volatility (Harvey, Leybourne, Sollis and Taylor, 2016; Harvey, Leybourne and Zu, 2019, 2020; Kurozumi, Skorobotov...

In this paper, we apply the wavelet methods in the popular Augmented Dickey-Fuller and M types of unit root tests. Moreover, we provide an extensive comparison of the wavelet based unit root tests which also includes the recent contributions in the literature. Moreover, we derive the asymptotic...

In this paper, we apply the wavelet methods in the popular Augmented Dickey-Fuller and M types of unit root tests. Moreover, we provide an extensive comparison of the wavelet based unit root tests which also includes the recent contributions in the literature. Moreover, we derive the asymptotic...

This paper demonstrates that unit root tests can suffer from inflated Type I error rates when data are cointegrated. Results from Monte Carlo simulations show that three commonly used unit root tests - the ADF, Phillips-Perron, and DF-GLS tests - frequently overreject the true null of a unit...

Ng and Perron (2001) designed a unit root test, which incorporates the properties of DF-GLS and Phillips Perron test. Ng and Perron claim that the test performs exceptionally well especially in the presence of a negative moving average. However, the performance of the test depends heavily on the...

In the absence of uniformly most powerful (UMP) tests or uniformly most powerful invariant (UMPI) TESTS, King (1987c) suggested the use of Point Optimal (PO) tests, which are most powerful at a chosen point under the alternative hypothesis. This paper surveys the literature and major...