To face the continuously intensifying conflicts surrounding large dam projects, the international World Commission on Dams (WCD) has developed a set of recommendations on how to attain the equitable and sustainable development of water and energy resources. One such recommendation emphasises the need to, in the first instance, carry out a comprehensive options assessment in which both positive and negative project impacts are taken into consideration. The WCD furthermore recommends that this necessary assessment be formalised through the use of multi-criteria decision analysis (MCDA), although MCDA has up until now seldom been applied to the large dam context. This thesis will therefore pursue three aims: 1. To improve the understanding of the decision situation 2. To investigate the applicability of MCDA, its compatibility with the guiding principle of sustainable development and the significance of its results. 3. To recommend methodological improvements. This dissertation offers an understanding of large dams and their complex interactions with the natural environment and society’s subsystems as a system and connects the MCDA theory to it. The thesis furthermore provides a link between the theoretical analysis of the strengths and weaknesses pertaining to MCDA – independent of its specific methods – and the findings of three analytical surveys, all of which bear direct relation to the comparison of large dam projects in practice. These surveys are: · A comparison of computer-aided MCDA-tools for the large dam context, regarding methodological and content-related strengths and weaknesses. · A retrospective quality analysis of a real-world application of one of the investigated tools for a large dam project in Laos. · A theoretical reproduction of the decision to build a large dam in Turkey in the 1970s, applying one of the investigated tools. The strengths of MCDA can be found in its formalisation of the procedure, while its weaknesses are caused by methodological problems posed by the individual steps of the analysis. It will be shown that MCDA can be used to support the comparison of large dam projects. Splitting the decision into several more manageable decisions formalises the procedure, improves the understanding of the decision situation, increases the transparency of the decision-making process for the public, and facilitates conflict management. In practice, the weaknesses of the procedure are considered to outweigh its strengths. This is in particular due to the formalised aggregation of objective and subjective information. MCDA methods can be misleading, due to their tendency to overemphasise numerical results. The significance of the results is limited by the complexity reduction required. In addition to this, the assumptions necessary to the methods are loaded with a high level of uncertainty and the many small decisions to be made transform meanings. These effects interact in an irreproducible manner when integrated into an overall result. At the same time, it is impossible to validate the methods and to compare the individual methods with each other. Therefore, even the choice of a particular aggregation algorithm contains subjective preference information. As regards future application, MCDA should be broadened to include a form of quality management and its methods should only be understood as one element of a wider, explorative analysis of the decision situation. It will furthermore be necessary to create decision-making structures which avoid the export of problems into other sectors and which mediate between different interests.