People make many choices every day in life. These choices can take place at the level of their individual situations, organization and/or the government. Depending on the importance of the decision and the number of objectives/criteria, suitable decision making tools should be used. Analytic Hierarchy Process (AHP) is a commonly applied decision making method. While reaching out to a conclusion, a decision maker may encounter with vague circumstances. This problem can be handled with the use of fuzzy set theory. By utilizing from a specific subject of fuzzy set theory, which is Interval Type-2 Fuzzy Sets (IT2FS)’s, calculations are able to be done for considerable uncertain conditions. AHP method with Interval Type-2 Fuzzy Numbers (IT2FN)’s is found in the literature. Since AHP method with IT2FN can be used for the cases that contain only main criteria is not much useful with in large quantities of criterion, it is thought that the development of the structure in the fuzzy method will contribute to the literature. The aim of this study is to expand the hierarchy of AHP via using sub-criteria for IT2FN. This expansion of the formation is called multilevel hierarchy. Because of the fact that real life may contain more than a few attributes, this approach allows managing more realistic situations. An encountered car selection problem is worked out for illustration of the extended method.
Anahtar Kelimeler: Analytic Hierarchy Process, Interval Type-2 Fuzzy Sets, Multilevel Hierarchy, Car Selection