# In this study the input and output data as

Nowadays, PV companies must focus on their changes in dynamic operational efficiency because the sustainable development of a PV company requires a long time planning with high investment [30]. According to the concept of carry-over, some activities will continuously engage in the business of companies in each period. For example, the material inventory will be accumulated and carried forward from one BHQ to another to meet production requirements. Corresponding to these activities, the dynamic evaluation process is described in Fig. 1. As can be seen, there is a DMU over T periods. At each period t, each DMU has inputs, outputs and carry-over terms to the next period (t + 1). In this study, the PV companies involved are continuums for the time period from 2009 to 2013, and each company is considered as a DMU in the model. The inputs for each company are employees, debt capital and equity capital, where both the debt capital and equity capital are carry-overs (links) of the inputs. Revenues are the output for each company. The dynamic efficiency at period t will be calculated by the dynamic SBM model in terms of the above data.