تحلیل سلسله مراتبی فازی درجه بندی شده برای انتخاب معاملات حساب جاری بانکی

Fuzzy AHP is a hybrid method that combines Fuzzy Set Theory and AHP. It has been developed to take into account uncertainty and imprecision in the evaluations. Fuzzy Set Theory requires the definition of a membership function. At present, there are no indications of how these membership functions can be constructed. In this paper, a way to calibrate the membership functions with comparisons given by the decision-maker on alternatives with known measures is proposed. This new technique is illustrated in a study measuring the most important factors in selecting a student current account.

Despite the popularity and simplicity of the Analytic Hierarchy Process (AHP), it is often criticised for its inability to adequately handle the uncertainty of a decision maker’s preferences. In classic AHP, the judgements are represented by exact values on a scale of 1–9 (Saaty, 1977 and Saaty, 1980). However, in many real cases, the linguistic assessments of human evaluations are often vague, and it is not realistic to represent them with crisps values. To overcome these shortcomings, fuzzy AHP has been developed to take into account this uncertainty and imprecision. It is essentially the combination of two methods: fuzzy set theory and AHP (Van Laarhoven & Pedrycz, 1983). Fuzzy set theory requires the definition of a membership function for each verbal judgement. However, in all papers reviewed, there was no indication of how the membership functions have been selected. This paper proposes a way to calibrate the membership functions with comparisons given by the decision-maker on alternatives with known measures. In this case, we asked to compare the surface of geometrical figures and as a result, the membership function was personalised for each participant. Then, the fuzzy AHP with the customised membership functions is applied to a case study in order to establish the most important factors in the selection of a student current account. We found that service is the most weighted criteria when selecting a bank account.

The contribution of this study can be viewed from both a theoretical and practical dimension. Theoretically, this paper presents a new customised fuzzy-AHP method. Practically, it provides insight into criteria selection for bank accounts among students. When data are precisely known, they can be represented with crisps numbers. However, in most real-world situations, data cannot be assessed precisely because it is unquantifiable, incomplete, undisclosed or vague. Decision-makers are often uncertain in assigning the evaluation with conventional AHP, therefore a hybrid multi-criteria technique is used. Linguistic terms have been introduced to better mirror the vagueness and subjectivity of the evaluation. These are then translated into numerical values with fuzzy formats described by membership functions. In previous work, the construction of membership functions was never discussed and was the same for every decision-maker. In this paper, a new process to calibrate these functions according to the decision-maker’s subjectivity is proposed. This significantly contributes to more precise and customised results. The methodology provides an effective tool for evaluating fuzzy representations and for modelling subjective and ambiguous situations. Due to the customisation of each personal verbal evaluation, the tool’s adaptability is enhanced for multiple criteria group decision-making problems in a ‘fuzzy’ situation. To illustrate this new customised fuzzy-AHP method, a study on the importance of the criteria for selecting a bank account for students was conducted. As the research was for illustrative purposes, it should be considered explorative. The sample was small but some conclusions were drawn nevertheless. The face-to-face collection of data was the most effective collection method, with a much higher response rate and consistency index. The study highlighted once more in the academic literature the importance of service in the banking sector and found that financial factors were less important. Bonuses were more attractive to international students and therefore; it is not surprising that several UK banks prefer to offer bonuses than attractive financial conditions. It is essential to understand the preference of the consumer and to have a strategic design in place to meet their expectations. The findings of the study serve as a starting point for bank managers to understand the importance of the selection criteria, however, further studies on a larger scale are needed to confirm these observations. On the methodological part, the fuzzy calibration methodology is very versatile and flexible in its areas of applications and integration with other methods. Future studies could combine the fuzzy calibration methodology with other MCDA techniques, such as TOPSIS, PROEMTHEE and ELECTRE.