Abstract

Recently, a relatively new methodology named directional distance function (DDF) has been attracting positive attention in the field of energy and environmental (E&E) modeling. However, there is still no literature review on the application of DDF in E&E studies. This paper is intended to fill this gap. First, the most widely used DDF techniques and its extensions are briefly introduced. Second, this article attempts a classification of typical publications in this field. The main issues raised by the previous studies are discussed. Some guidelines for model selection and future directions are proposed for DDF related research in E&E studies.