Decision making in coastal zones mostly deals with problems which have not only monetary aspects, but are also concerned with values connected to social, or ethic aspects or refer to environmental qualities. In these cases the support given to decision making by economic evaluation methods may be less useful, and there may be a need for additional methods which are able to consider also non quantitative measures of values. This group of methods is normally referred to as Multicriteria techniques.
The terms Multicriteria Analysis (MCA) and Multicriteria Decision Analysis (MCDA) refer to a group of formal approaches to the analysis of decision processes and problems, which aim at determining an overall preference among different alternatives. Each alternative under examination is evaluated on the basis of its performance with respect to a body of decision criteria. The criteria to be used for evaluation can cover economic as well as social and ecologic aspects so that Multicriteria Decision analysis offers the possibility to integrate into the decision process both easy to be quantified economic and non-economic aspects, which cannot be quantified (or are difficult to be quantified) in monetary terms. Multicriteria Analysis thus opens the prospective of evaluation beyond criteria based on economic efficiency (i.e. cost-benefit analysis) by allowing the consideration potential social and ecologic impacts of each possible intervention. A further advantage of Multicriteria approaches over economic valuation techniques is that impacts measured in different units can be considered simultaneously. Thus, a variety of the decision criteria, as well as inconsistent or incomplete judgements/preferences, can be considered in the analysis of alternatives.
For the application of MCA approaches to decision making, Belton and Stewart suggest the consideration of three distinct phases: problem structuring, model building and use of the model for informing and challenging thinking.
- The problem structuring phase is used to define the terms under which a decision making problem is considered, stakeholders to be included into the decision making process, the collection of information regarding the criteria for decision making to be considered. A combination of deliberative techniques can be used for the active involvement of relevant actors.
- The model building phase is dedicated at the definition of criteria and of the relative importance or value attributed to each of the criteria by different stakeholders.
- The application of the model using weights to determine the value of each criterion within the framework or model and scores to determine the performance of each alternative with regards to each criterion may bring directly to a decision or result in feedbacks to the previous phases to revise the definition of the problem, the choice of criteria etc.
According to the model of MCA applied, values can consist in degrees of preferences, expressed in numerical scores, levels of achievement for each criterion, or in the result of outranking, based on direct confrontation between alternatives.
MCA is both a framework for a decision analysis, consisting of steps and procedures for a piecewise conceptualisation of problem involving multiple objectives and criteria, and a set of techniques aiming at elicitation, introspection and aggregation of decision preferences. Consequently, MCA represents added value to both
- the decision process, by helping the decision-maker know more about the decision problem and explore the alternatives available; and
- the decision outcome, by helping elicit value judgements about trade-offs between conflicting objectives).
In this latter respect, MCA is therefore useful for classification, determining priorities or selecting between alternatives, for instance different options for coastal protection, especially in cases when the different alternatives perform better than others with respect to certain criteria, and worse with respect to other criteria. In these cases the use of MCA tools is particularly interesting for the direct participation of stakeholders, as it allows for visualizing different perceptions of the relative importance of the criteria by different groups, highlighting how results can change if different stakeholders’ interests and perceptions are taken into account. MCA techniques thus provide a platform for consensus reaching. Moreover, MCA techniques not only help find a solution to a multicriteria problem, but also to give the decision-maker an opportunity to learn about his/her own preferences and those of the involved stakeholders.
Hence, the Multicriteria approach is generally acknowledged to be a very suitable instrument not only to assess sustainability, but also to carry out the decision process in a ‘sustainable sound’ way. Indeed it allows the direct participation of stakeholders in the evaluation of alternatives, and the identification and discussion of trade-offs and conflicts of interests in order to build consensus. Given the high flexibility of the tool, its application is possible at both the planning and the project levels.
The NetSyMod framework  (“"Network Analysis - Creative System Modelling - Decision Support"”) aims at integrating the multi-step MCA approaches with DSS tools into a comprehensive tool for the management of natural resources.
- Belton, V., Steward, T. (2002) Multiple Criteria Decision Analysis, An Integrated Approach. Boston: Kluwer.
Saaty, T.L (1990) Multicriteria Decision Making: The Analytic Hierarchy Process, Vol. 1, AHP Series,RWS Publications, 502 pp., 1990 extended edition. This is the original theoretical and technical book containing a rigorous treatment of the Analytic Hierarchy Process.
von Winterfeldt, D., Edwards, W. (1986) Decision analysis and behavioural reserach, Cambridge University Press.
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