Using ANP and AHP for the supplier selection in the construction and civil engineering companies; Case study of Iranian company

The experts of the construction and civil engineering companies are responsible for selecting an appropriate supplier. Evaluation and selection of appropriate suppliers may decrease quality deficiency, cost overrun, environmental problems and etc. In this research a decision support system is developed to select appropriate supplier for construction and civil engineering companies. The effective criteria on the supplier selection process have been investigated and accommodated to internal structure of the Iranian construction and civil engineering companies by questionnaire survey. For this purpose, the current research carries out among logistics managers of the first grade Iranian construction and civil engineering companies or those with having ISO certification. After completion of questionnaires, the effectiveness of criteria is evaluated using t-student test. Five criteria are excluded, and 18 criteria are selected as effective criteria. To select appropriate supplier, the AHP and ANP approaches are utilized simultaneously. Since, these two methods use a limited number of criteria, it is essential to prioritize criteria. So, Friedman test is applied and finally five of the most important criteria have been employed. Unfortunately environmental issues are not attended by construction and civil engineering companies. To illustrate concept and performance of proposed decision support system three candidate suppliers are ranked using AHP and ANP models. Although the final results of AHP and ANP methods are the similar, the values of variation between suppliers are different. Therefore, it is recommended to employ the ANP method considering internal relations between criteria.