Background
The Delphi technique is a structured approach to group communication process developed by the RAND Corporation in the 1950s to obtain more reliable opinion from knowledgeable individuals [Despite the “fixed” components that are its hallmark, Delphi studies show great variability in their implementation. Over the years, many reviewers have criticized and attempted to overcome the lack of guidance compromising the validity of Delphi outputs [However, the choice of assessment procedure to quantify the opinion of panel members is a key methodological aspect of the Delphi technique that has remained unexplored to date. In this regard, rating and ranking are the most commonly used [Most of the empirical literature to date comparing rating and ranking is in the field of value systems measurement in psychology [