Supplier selection with utility range-based interactive group decision method

Particularly, we look at recent years, outsourcing, supply-based trends such as downsizing and mergers have increased. Customer orientation has become an indispensable element. In the competitive environment, a firm's performance doesn?t depends on only its abilities but also depends on its suppliers. To sustain its competitiveness, the importance of choosing suppliers is increasing. Suppliers to keep pace with this competitive environment, they should be supply the company requests with the desired quality, speed, condition and time.Increase in costs of supply, increases the importance of supplier selection. In high-tech products, the majority of the cost of the finished product may occur parts which are provided from suppliers. In manufacturing enterprises; the cost of supplied parts can reach high proportions. In some industries, suppliers are now a strategic partner. Services can also be supplied from suppliers. The service is purchased benefit. The service provider selection becomes even more complex because of intangible. The price and different factors come into.Large-scale firms, this process makes it necessary to decide with the group, but the decision makers do not have full knowledge about the topic. Supplier selection is a multi-criteria decision making problem. The supplier selection problem is intended to select the most suitable supplier in line with business requirements. Error made in choosing suppliers, while ensuring the relationship between suppliers fails. This means high cost and loss of market, demand, time.In this thesis, performance evaluation and selection of service suppliers made by using range type utility based interactive multi criteria group decision making method which has been developed. I use incomplete information for decision makers? preferences because of the difficulty of preferences for group members to express the exact cause. Range type makes the incomplete information effective and efficient to demonstrate the group members. In addition to this, range type utility information makes easy to compare every group members? utility information with group?s information and collecting the each group member?s utility information within group?s utility information.By the method, the decision-makers range type utility information was transformed the group?s range type utiliy information. The supliers? utiliy information calculated by using optimism coefficient which is determined by the group. The supplier which has the highest utility is selected. Also aimed to minimize the regret caused by the selection. Selection of service supplier is the difficult and important problem, aimed to solve considering the company requests and properties of service.