sustainable construction project portfolio selection under interval- valued type-2 fuzzy sets

choosing the right set of projects is the first step of project oriented firms in strategic project portfolio management. since economic growth depends on environmental and social issues, sustainable development has been an essential part of firms' plans to keep their competitive advantage. moreover, market conditions, fast worldwide changes and other similar issues have given these issue ever-growing uncertain elements. as a result, this paper provides a method of sustainable construction-project portfolio selection under interval-valued type-2 fuzzy sets. this method consists of two main parts. the first level evaluates the proposed projects and omits the unsuitable ones. then, in the second level, the portfolio is selected by means of mathematical programming. eventually, to display applicability of the method, an application example is presented and solved.