Environmental Assessment on Energy and Sustainability by Data Envelopment Analysis

19MEASUREMENT IN TIME HORIZON

19.1 INTRODUCTION

This chapter ¹ describes how to assess the performance of decision making units (DMUs) in a time horizon. To explore the research issue on time series data, this chapter formulates radial models under natural or managerial disposability and then extends them to time series analysis. The proposed approach uses the radial measurement discussed in Chapter 17 for time series analysis because the radial framework has an inefficiency measure (ξ) that is unrestricted in its sign. In contrast, the non‐radial models discussed in Chapter 16 cannot be directly applied to the proposed framework for time series because it does not contain an inefficiency measure. Non‐radial measurement needs to use another computational framework (e.g., window analysis) for a time series. See Chapter 26 that discusses non‐radial measurement by window analysis. In the proposed time series analysis, a negative inefficiency measure indicates a frontier progress and a positive inefficiency exhibits the opposite case (so, no frontier progress). Thus, this chapter uses radial measurement to examine whether the frontier shift occurs among different periods.

To document the practicality of the proposed approach, this chapter applies radial measurement to performance assessment of the electric power industry of ten Organization for Economic Co‐operation and Development (OECD) nations from 1999 to 2009. The application is useful for developing green growth in economy and pollution ...