Allameh Tabataba'i University Press Journal of Mathematics and Modeling in Finance 2783-0578 2 2 2022 12 01 Introduction a method of determining returns to scale in network data envelopment analysis 15 36 15184 10.22054/jmmf.2023.15184 EN Hadi Bagherzadeh Valami No 17,8th alley, varze street, West ferdos boulivard, Tehran Zeinab Sinaei Nasab Applied mathematics, Yadegar-e-Imam Khomeini (RAH) Shahre Rey Branch, Islamic Azad University, Tehran, Iran Journal Article 2022 06 20 In the process of evaluating the Decision Making Units, two factors of efficiency and production size can be used. When the production size of a unit is not optimal, its Returns To Scale (RTS) determines that changing the resources in another<br />direction would enhance its productivity. In most previous research, RTS is considered to be increasing or decreasing, and frontier analysis is used to determine it. The concept of RTS in Network Data Envelopment Analysis (DEA) is so interesting. In this paper a method based on Most Productive Scale Size (MPSS) in several steps is developed, in addition to determining that RTS of units for each unit in directional manner, the shortest changes in resources for achieving the right size for network production is also obtained. In this approach, the computational complexity, and the ambiguity in units RTS is not present. https://jmmf.atu.ac.ir/article_15184_47438e00fb33f5edd832109a766f7fab.pdf