Foreword

Real-world problems and decision situations generally involve the need to consider explicitly multiple,, conflicting and incommensurate evaluation aspects. This fact is generally recognized as the starting point of multiple criteria decison aid (MCDA) as a scientific discipline, although some authors consider the multiple criteria approach as essentially an "act of faith" (Bouyssou, 1993). Even though the real-world application (with the meaning: whenever someone pays for it!) of the large corpus of techniques and methods MCDA has been developed lags well behind the theoretical and methodological advances, reports on MCDA in practice are steadily growing in the scientific literature. For instance, White (1990) presented a survey listing more than 500 references covering the period 1955-86 (excluding those approches which used an a-priori explicit value function). However, one must realize that just a small number of cases actually involves an implementation phase (and most of those seems to be goal programming-based studies). The improvement of the implementation rate of MCDA studies should be a crucial concern of MCDA researchers and practitioners, namely having in mind the conceptual and operational validation of the use of MCDA techniques in real-world problems with actual decision makers (Bouyssou et al., 1993). This trend to emphasize actual studies, as well as the search for new potential areas of application, also contributes to make MCDA to receive further cross-fertilization from other scientific disciplines. Nevertheless, it is fair to recognize that real-world applications are not easy to get from organizations (both in public and private sectors) even in a free an researchoriented basis. Under these (difficult) circumstances, sound academic case-studies (clearly assumed as such) supplied with realistic data may have an important role to play, not just as valuable experimentation frameworks, but also as evangelization tools to show the potential benefits which can be harvested from an MCDA approach in complex decision situations.