“…This is partially attributable to the significant country differences in the status and policies of green economy. On China's green economy, the existing research methods can be divided into four categories: data envelopment analysis (DEA) (Guo et al, 2017;Bao, 2017;Marino et al, 2017;Yan, 2017Yan, , 2018Shen et al, 2017;Han et al, 2018;Song, 2018), the stochastic impacts by regression on population, affluence and technology (STIRPAT) , the logarithmic mean Divisia index (LMDI) model (Wang and Feng, 2018;Chen, 2018), and the GML/ML index. Coupling the DEA and the directional distance function (DDF), the ML index was modified from the Malmquist index (Chung et al, 1997), which is traditionally calculated from the output distance between different technologies.…”