Summary of the technology
The ELECTRE-H Software Package implements two new methods for ranking and ordered classification decision problems considering multiple criteria structured into a hierarchy. The hierarchy of criteria is a tool that allows the decision maker to better organize the problem based on its domain knowledge and needs, decomposing the general problem into smaller sub-problems. Both methods follow the well-known outranking model and belong to the family of ELECTRE methods. The ELECTRE approach is inspired on the voting-like procedure based on the opinion of the majority but also respecting the minorities (by allowing veto power). The software available to use ELECTRE methods does not allow a hierarchical decomposition of the problem, but on a flat organization of criteria.
The novelties of these two methods are the following:
-It fully applies the standard outranking procedure of ELECTRE at all the levels of the hierarchy of criteria (concordance and discordance indices are obtained from the results of the previous layer and exploited at each node to generate new results).
-The user will get a result (a ranking or classification) at each intermediate node of the hierarchy as well as the root (or overall) node.
-Preference uncertainty can be managed at each node of the hierarchy with its particular discrimination threshold values.
-Veto power can be given to the appropriate nodes in the hierarchy, to avoid compensation with the rest of related criteria.
-Different scales of measurement can be used both in the elementary criteria and in the intermediate criteria.
-For the case of sorting, simple IF…THEN… decision rules are used to define the categories.
The novelty of the software ELECTRE-H is that it is the implementation of these methods given by the authors. This guarantees that the program is fully following the methodology proposed. Its main features are:
-Clear and easy-to-understand user interface.
-Data can be easily provided using an Excel file.
-All the parameters of the model can be easily changed in the user interface.
-The results obtained can be graphically displayed (i.e. partial pre-orders, rankings) and exported into a PNG image or text files. Also, the calculations of the results are provided in log files.
-Additional statistical tools to compute correlations for different ranking and classification results on the same set of alternatives and hierarchy are available.
-A distance-based statistical tool to compare partial preorders is available.
-The “Simos revised procedure” to calculate numerical values for criteria weights is available.
-Analysis of the results can be done at different levels of the hierarchy.
-The software supports large number of alternatives and criteria. Also the structure of the hierarchy is only limited to be a tree (each node has a single parent).
The software is designed to be easy to use while providing the full functionality required in these two methods.
Description of the technology
The ELECTRE-H software helps decision makers to rank or classify a predefined set of alternatives, considering several conflicting evaluation criteria structured in a hierarchy of related criteria. The software provides partial results at all levels of the hierarchy for a better analysis based on the decision maker’s preferences.
The ELECTRE-H for hierarchical sets of criteria was defined by Dr. Del Vasto and Dr. Valls (from URV) and Dr. Slowinski and Dr. Zielniewicz (from Poznán University of Technology, Poland). The papers can be found here:
ELECTRE-H software package is a program written in Java language. It may be executed in any computer that has a Java Virtual Machine (JRE), which is usually pre-installed in many computers by default. It is a desktop application where the user can upload an Excel file that includes the basic input data to be analysed. It consists on: - A set of alternatives: these are the objects or options that the user wants to evaluate, compare and rank or classify. For example, a set of candidates to a job, or a set of websites, or a set of locations for an energy plant, etc. - A set of elementary criteria: these are indicators that can be measured on the alternatives and can be used to know which alternative is better for the user. For example, years of experience and average grade may be criteria for the candidates to a job, whereas the number of links and the quality of images can be indicators to evaluate and rank websites. - A grouping of elementary criteria into one or several intermediate criteria. For example, when evaluating job candidates we may have a subset of criteria related to expertise, another set of criteria related to personal capabilities and another one related to previous formation, etc. These intermediate level represents different aspects that are of interest to arrive to the final solution. - Some other parameters are needed like: relative importance of the criteria, indifference thresholds, preference information, etc. Once the input data is uploaded into the system, the user can visualize it and run the algorithm to obtain the result in form of a partial-preorder (i.e. a preference ranking) of all the alternatives, or a classification of the alternatives into a predefinite set of categories. These result is given for each intermediate criterion. The tool additionally may generate some graphics and make some statistical analysis of the results.
Main advantages of its use
- The ELECTRE-H software is a generic decision aiding tool and thus, can be applied for any decision problem in any field, specially suited for multiple conflicting objectives inherently involved in decision problem, such as economic, environmental or social criteria. Thanks to possibility of decompose a decision problem into a hierarchy of criteria, the decision maker can better organize the problem based on its domain knowledge and needs, as well as a better analysis of the decision problem results due to partial results obtained from the methods applied. Following the outranking approach in decision aiding, the tool allows the decision makers to set preferences and weights of each sub problem in the hierarchy.
- Public and private organizations face decision problems that include multiple conflicting criteria on a daily basis. Following the extensive application of the ELECTRE methods in several fields for different purposes, the ELECTRE-H software provides a hierarchical decision analysis tool suited for any field including environmental and water management, finance, project selection or personnel recruiting.