en عمومى General پژوهشي Research <span style="font-size:11pt"><span style="line-height:normal"><span style="unicode-bidi:embed"><span sans-serif="" style="font-family:Calibri,"><span new="" roman="" style="font-family:" times="">The inverse data envelopment analysis (InvDEA) technique is an applicable method in order to estimate the input/output levels of decision-making units (DMUs) to preserve predetermined technical efficiency scores. In the managerial atmosphere, the decision maker (DM) aims to merge two or more units and needs to know the input/output levels of the merged unit, while the efficiency score of the new unit is set, however, in some cases, the units have two-stage network structures. The main purpose of this paper is merging DMUs with two-stage network structures. To reach this goal, in this paper, an InvDEA method is presented in order to estimate inputs and the intermediate products of two-stage DMUs, to achieve the different predetermined efficiency scores which have been set by the DM.</span></span></span></span></span> Inverse DEA, Network DEA, Two-Stage Systems, Merge and Aggregation 39 49 http://ijorlu.lahijan.iau.ir/browse.php?a_code=A-10-533-1&slc_lang=en&sid=1 Z. Shiri Daryani shiridaryanizahra@yahoo.com 10031947532846001698 10031947532846001698 No Department of Mathematics, South Tehran Branch, Islamic Azad University, Tehran, Iran Gh. Tohidi gh_tohidi@iauctb.ac.ir 10031947532846001699 10031947532846001699 Yes Department of Mathematics, Central Tehran Branch, Islamic Azad University, Tehran, Iran B. Daneshian b_daneshian@azad.ac.ir 10031947532846001700 10031947532846001700 No Department of Mathematics, Central Tehran Branch, Islamic Azad University, Tehran, Iran Sh. Razavyan sh_razavyan@azad.ac.ir 10031947532846001701 10031947532846001701 No Department of Mathematics, South Tehran Branch, Islamic Azad University, Tehran, Iran F. Hosseinzadeh Lotfi farhad@hosseinzadeh.ir 10031947532846001702 10031947532846001702 No Department of Mathematics, Science and Research Branch, Islamic Azad University, Tehran, Iran