Assessing structural uncertainty caused by different weighting methods on the Standardized Drought Vulnerability Index (SDVI)

Indices are used for representing complex phenomena; however, concerns usually arise regarding their objectivity and reliability, particularly dealing with their uncertainties during the development process. The current overarching objective is to reveal the significance of employing different weighting techniques in the application of the Standardized Drought Vulnerability Index (SDVI) and demarcate any pertinent implications that may emerge in drought decision making. Greece, as it is very often facing the catastrophic effects of droughts, presents an almost ideal case for the SDVI testing. SDVI outcomes were tested utilizing five weighting techniques deriving from four weighting methods. The analyses indicated that the use of complex weighting models may not be necessary in all cases and that the simple equal weighting method seems more effective to estimate drought vulnerability. It also seems more important to address the search for valid, reliable and relevant individual indicators forming the complex index as well as appropriate index development processes that would measure performance of water bodies, systems and schemes, monitor the process of equitable sharing, and provide mechanisms for monitoring the state and changes in interdependent water systems.