Unit root and trend breaks in per capita output: evidence from sub-Saharan African countries

摘要

This article examines the nonstationary properties of per capita real output in 28 sub-Saharan African (SSA) countries, covering the period 1960-2014. The sequential testing approach proposed by Kejriwal and Lopez (2013, Econometric Reviews 32(8), 892-927) is used to categorize SSA countries into growth shift, level shift and linear trend hypotheses based on the presence or not of breaks in slope and/or level of the trend function. The break dates are associated to major historical or economic events such as sociopolitical crisis, commodity price fluctuations on international market, the discovery and the exploitation of mineral deposits or unfavourable environmental and climatic conditions. The empirical evidences of appropriate unit root tests fail to reject the unit root hypothesis in all the countries, suggesting that a shock would have a permanent effect on growth process, and stabilization policies may be implemented in dealing with income fluctuations.