The paper deals with a complex decision making problem, the evaluation of Learning Management Systems, where several conflicting objectives, like environmental, social and economic impacts, must be simultaneously taken into account. Multi-Attribute Decision Support Models are typically developed through the decomposition of complex decision problems into smaller and less complex subproblems; the result of such decomposition is a hierarchical structure that consists of attributes and utility functions. We introduce an approach to the development of Multi-Attribute Decision Support Model that is based on an expert system shell for multi-attribute decision support and illustrate its usefulness by showing its main features and its application to the above intervention problem.