fa تخصصي Special پژوهشي Research <p>In conventional DEA models, decision making units (DMUs) are generally assumed as a black-box while the performance of decision making sub-units (DMSUs) and their importance play crucial roles in&nbsp; analyzing the performance of systems which have internal processes. The present paper introduces an ideal network which have efficient processes and next purposes a new approach for evaluating importance of network components (DMSUs) based on comparison with the ideal network. Eventually, overall efficiency of network system will be determined which can be decomposed to the weighted efficiency of its sub-processes. As the result of the purposed approach, we can determine the situations that the network would perform better by improving the efficiency of the important DMSUs which have a vital impact on network performance.</p> Data envelopment analysis, Network systems, Importance of subunits, Overall efficiency 65 75 http://ijorlu.lahijan.iau.ir/browse.php?a_code=A-10-1-158&slc_lang=fa&sid=1 R. Kazemi Matin rkmatin@kiau.ac.ir 1003194753284600621 1003194753284600621 Yes Associate professor, Department of Mathematics, College of Basic Sciences, Karaj Branch, Islamic Azad University, Karaj, Alborz R. Azizi 1003194753284600622 1003194753284600622 No MSc graduated, Department of Mathematics, College of Basic Sciences, Karaj Branch, Islamic Azad University, Karaj, Alborz M. Bakhsh Mohammadlou 1003194753284600623 1003194753284600623 No MSc student, Department of Mathematics, University of Tafresh, Tafresh A. Habibi Nezhad 1003194753284600624 1003194753284600624 No MSc student, Department of Mathematics, University of Tafresh, Tafresh