Distinct orders of priorities for the demands shared by diverse stakeholders create a complex system of interests. The ability to argue can bias the collective ranking of priorities, discouraging people to get engaged in the fulfillment of the diverse demands. It is supposed that the motivation of a group in implementing actions is proportional to the compatibility of the original ranking or the re-ranking of priorities based on individual reflections regarding what others give priority. In the method here proposed, the identification of the degree of conformity among distinct interests is a mathematical product of the relations among the original rankings, while the promotion of a higher convergence of these rankings is mediated exclusively by individual reflection. As an indicator of sustainability to be derived, the degree of compatibility of the distinct interests that drive the distinct rankings is characterized as a measure of the possibilities of effective engagement of all interested. The systematization of relations resulted in an objective and operational Indicator of Sustainability in a System of Interests - 0 < ISSI < 1.
indicator of sustainability; systems of interests
