Connected Directional Slack-Based Measure of Efficiency in DEA

In the history of DEA, there are two fundamental “Radial” and “Non-radial” approaches for the efficiency measurement. Each approach has its own advantageous and shortcomings. Avkiran et al. (2008) provided a unified framework, named Connected-SBM, for linking these approaches. In the present paper, first, based on the directional distance function we develop the Directional Slack-Based Measures (DSBM) of efficiency under Generalized Returns to Scale * Corresponding author. E-mail addresses: [email protected] (M. Mehdiloozad), [email protected] (I. Roshdi) 238 G. R. Jahanshahloo et al (GRS) which has many attractive properties. Secondly, employing the DSBM, we develop a generalized form of the Connected-SBM model, so-called Connected-DSBM. Our proposed model is more flexible than the Connected-SBM model. In addition, the Connected-SBM and many of the well-known DEA models, e.g., the CCR, BCC, ERM and SBM models, are derived from it.