Selecting a cleaning company with fuzzy multi-criteria decision making

In daily life, supplier selection turns into a difficult problem to decide in terms of cost and benefit. In these choices, too many criteria can be used for companies, which makes the solution difficult. As a result of this difficult decision, companies can make wrong choices. For this reason, it is important to use the scientific methods developed when choosing between alternatives, and these methods both enable us to make easier decisions and enable us to make more correct decisions. Especially in the selection of suppliers in the public sector, which is considered as outsourcing, the selection is usually made by considering the cost criteria, and these decisions can lead to wrong choices. First of all, the necessary need in the public sector is determined and the companies are made to participate in the tender by making an announcement according to this need. In the solution of multi-alternative and multi-criteria problems such as supplier selection, multi-criteria decision making methods used in the literature are utilized in order to make correct decisions. By using the methods of MCDM (Multi-Criteria Decision Making), decision makers evaluate each alternatives on the basis of each criterion, respectively, and find best solution that gives the best result when all desired criteria are considered concurrently. Today, fuzzy methods are widely used instead of classical methods in MCDM. Thanks to fuzzy methods, it is easier to make the right decision between criteria and alternatives by using linguistic expressions instead of a clear numerical equivalent of the data. Considering the literature, although the problem of supplier selection is encountered with Fuzzy AHP and Fuzzy TOPSIS methods, there is little work done in this field, especially in the public sector, and the problem of choosing a cleaning company has been taken into account in this study. Outsourcing companies were compared using the fuzzy significance scale conversion scale proposed by Chang. According to the data obtained, a selection was made among the companies by using Fuzzy AHP and Fuzzy TOPSIS methods. The study has been applied in the public sector as an alternative method to outsourcing company selection by tender method and it is thought to be beneficial. Keywords: Multi Criteria Decision Making, Fuzzy AHP, Fuzzy TOPSIS, Supplier Selection, Outsourcing, Public Sector