Despite the rising profiles of both shale oil and shale gas plays in the U.S. and the importance of testing for their persistence, no study has examined the persistence of the availability of shale oil and shale gas plays in the country. This paper focuses on the analysis of shale oil and shale gas production using long range dependence techniques in the U.S. for the period, January 2000 to April 2019. The empirical findings illustrate that the series examined are highly persistent, finding very little evidence of mean reverting patterns. Among the implications of the results, which are discussed in the paper, is that there is a hysteresis in shale oil and gas production in U.S., and therefore shocks resulting from new government policies relating to shale oil and gas in U.S. will have lasting impacts on their production. Besides, it will not be feasible to use forecasting as a basic instrument for unconventional energy sources as the previous values of shale oil and gas production cannot be utilised to accurately forecast their subsequent values. (C) 2020 Elsevier Ltd. All rights reserved.