Most economic series have been analyzed on the assumption that they are integrated of order d that is I(d), where d is an integer. Such series exhibit a short memory process characterized with exponential decay in the autocorrelation function (ACF) sometimes with alternating signs after dth...

This paper examined the long memory features of GDP per capita data before the global financial crisis, using a sample of 26 African countries. The study employed fractional integration and tested the stability of the differencing parameter across the sample period for each country. The results...

Long memory and nonlinearity are two key features of some macroeconomic time series which are characterized by persistent shocks that seem to rise faster during recession than it falls during expansion. A variant of nonlinear time series model together with long memory are used to examine these...

This paper employs a comprehensive set of “state-of-the-art” unit root tests, including the autoregressive neural network (ARNN) unit root test (Yaya et al. 2021; Oxford Bulletin of Economics and Statistics), to investigate unemployment hysteresis in five European countries: France, Italy, the...

This paper initiates a non-linear fractional unit root test also known as autoregressive neural network–fractional integration (ARNN–FI) test. The test is based on a new multilayer perceptron of a neural network process which is applied in Yaya et al. (2021). Further, to investigate the...

The infant mortality rates in 45 Asian countries (1960-2018), obtained from the Federal Reserve Bank of St. Louis database, are investigated using the I(d) framework, which allows for simultaneous estimation of the degree of persistence and nonlinearities in infant mortality rates as well as...