Abstract
The purpose of the paper is to analyze two semi-quantitative methods of quantifying and ranking risk in order to achieve increasingly effective risk management: the Analytic Network Process (ANP) and the Interdependencies Model (IM). ANP is commonly used to make decisions in situations when multiple and conflicting objectives/criteria are present and it is necessary to deal with feedback between elements. The Interdependencies Model, based on the mathematical power method, is a means of taking into account complicated interdependencies between hundreds of items. With respect to risk management, both of them seem particularly useful for identifying and prioritizing risk factors to reach a chosen objective, assessing the combined risk involved in interdependent items. The present work begins with the description of the two methods at a theoretical level in order to clarify the necessary input data, the assumptions, the mechanism and the results supplied. Afterwards, the most relevant common elements and distinctive features are highlighted and the two methods applied in the case study of Lusoponte: a project regarding the construction of two bridges over the Tagus in Lisbon, Portugal. Through the application of both methods, the improvement in project risk management that could be obtained has been evaluated, and possible contexts in which these methodologies could be applied have been defined.