Long-term trends in non-renewable resource commodity prices: fresh evidence in the presence of structural breaks Online publication date: Wed, 01-Jul-2015
by Aviral Kumar Tiwari
International Journal of Global Energy Issues (IJGEI), Vol. 38, No. 4/5/6, 2015
Abstract: This study examines temporal properties of real price series of 11 natural resources covering the period 1870-1990 and utilising a recently developed unit root test proposed by Narayan and Poop and a stationarity test developed by Carrion-i-Silvestre and Sansó. We also employed a stationarity test developed by Lima and Neri. Results obtained from Lima and Neri's study provide evidence to reject the null hypothesis of stationarity for aluminium, coal, copper, petroleum, silver and tin, indicating that these series are I(1), while results from the Carrion-i-Silvestre and Sansó proposed test provide evidence to reject the null hypothesis of stationarity for aluminium, iron, tin and zinc, indicating that these series are I(1). The results obtained from the Narayan and Poop unit root test provide significant evidence of stationarity for aluminium, copper, lead, silver, gas and zinc, indicating that only these variables are I(0).
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