en عمومى General پژوهشي Research <p>&nbsp;</p> <p><span style="font-size:11pt"><span style="font-family:Calibri,">The slack based measure (SBM) of efficiency is one of mostly used model in the data envelopment analysis (DEA) literature. The model acts on inputs and outputs slacks and gave a measure between zero and unity. In the light of global warming and resource scarcity, some units widely consume undesirable (used) inputs for improving their efficiency. Plastic waste or Gray water production are two examples of undesirable input usage in recycling factories. Hence, increasing undesirable inputs raise challenges for handling in production process. This study contributes undesirable inputs through SBM model. Toward this end, the SBM model is developed to cases that consume both desirable and undesirable inputs to produce the final outputs. Addressing the increasing of undesirable input, SBM model is reformulated to identify not only corresponding reduction in desirable inputs but also anticipate a suitable quantity for the undesirable inputs. A real data set is applied to elucidate the model applicability and advantages. </span></span><br> &nbsp;</p> Undesirable inputs, Data envelopment analysis (DEA), Decision making unit (DMU), Slack based measure (SBM), Environmental assessment 51 61 http://ijorlu.lahijan.iau.ir/browse.php?a_code=A-10-529-3&slc_lang=en&sid=1 M. Maghbouli mmaghbouli@gmail.com 10031947532846002267 10031947532846002267 Yes Islamic Azad University, Aras Branch, East Azerbaijan, Jolfa, Iran. A. Pourhabib Yekta apouthabibyekta@yahoo.com 10031947532846002268 10031947532846002268 No Islamic Azad University, Sowmesara Branch, Guilan, Iran M. Zoriehhabib zoriehhabib_m@iaut.ac.ir 10031947532846002269 10031947532846002269 No Islamic Azad University, Soofian Branch East Azerbaijan, Iran