*2.2. AHP Online System-AHP-OS*

An AHP online software was used in order to implement the Multi-Criteria Analysis (MCA) with the method of the Analytical Hierarchy Process (AHP), which is called AHP Online System (AHP-OS), and can be found in the Business Performance Management Singapore (BPMSG) website [67]. This software provides a special excel sheet, in which all collected data are entered. It is a very simple and practical way of applying and completing an AHP which allows the user to directly configure the basic parameters of the process (number and name of criteria, size of input data, etc.). From a mathematical point of view, this method is based on the solution of an Eigen value problem.

The data must be quantified in order to import them into the software. More specifically, the quantification of the interviewees' answers is carried out according to the nine-point scale of Saaty. The software uses these quantitative data (numbers from 1 to 9) of all the comparisons between the

criteria and automatically calculates the weight of every criterion. During the data processing, a matrix is created in order to calculate the weight of every criterion and the consistency ratio. The result of every pair-wise comparison is placed into this matrix. The weighting of the criteria, which is the ratio scale, is given from the first dominant right Eigen vector of the matrix. It is essential to mention that a normalization of the quantified data is previously required in order to not import negative values. In this way, the final classification (ranking) of the criteria is made according to the weight of each criterion. Finally, the software can calculate the Consistency Ratio (CR). The CR is defined by the Eigen value of the matrix and it can lead to useful conclusions regarding the inconsistencies between the respondents' answers as well as the reliability of the AHP's final results [67].
