Fourier unit root and cointegration tests

Unit root and cointegration tests, which examine stationarity and cointegration in time series, are constantly evolving with new methods and studies. Fourier unit root tests and Fourier cointegration tests, which are developed by adding Fourier terms to the estimation equation, are among these. Structural breaks in time series can be examined by evaluating the changes in the series over time. Breaks that occur over time cause changes in the deterministic parts of the series. With Fourier tests, trigonometric terms are added to the model equation, thus eliminating the need to make a priori assumptions about the number, form and time of structural breaks. In this study, Fourier unit root tests and Fourier cointegration tests were examined. In this context, the long-term relationship between foreign debt and economic growth for the years 1970-2020 for Turkey has been examined with both traditional cointegration tests and Fourier cointegration tests. As a result of traditional and Fourier cointegration analyzes, it was found that there is a long-term relationship between external debt and economic growth.