Based on mathematics and sociology, the Promethee and Gaia method was developed at the beginning of the 1980s and has been extensively studied and refined since then.
It has particular application in decision making, and is used around the world in a wide variety of decision scenarios, in fields such as business, governmental institutions, transportation, healthcare and education.
Rather than pointing out a "right" decision, the Promethee and Gaia method helps decision makers find the alternative that best suits their goal and their understanding of the problem. It provides a comprehensive and rational framework for structuring a decision problem, identifying and quantifying its conflicts and synergies, clusters of actions, and highlight the main alternatives and the structured reasoning behind."
- Choice – The selection of one alternative from a given set of alternatives, usually where there are multiple decision criteria involved.
- Prioritization – Determining the relative merit of members of a set of alternatives, as opposed to selecting a single one or merely ranking them.
- Resource allocation – Allocating resources among a set of alternatives
- Ranking – Putting a set of alternatives in order from most to least preferred
- Conflict resolution – Settling disputes between parties with apparently incompatible objectives
PROMETHEE and GAIA belong to the family of multicriteria outranking methods as it was initiated by Bernard Roy at the end of the sixties with the ELECTRE methods. Outranking methods provide decision makers with an alternative to the aggregation methods that are popular in the US and the UK. Typically they require less information from the decision maker(s) and allow to keep closer to the actual decision problem.
The original PROMETHEE methods have been conceived by Jean-Pierre Brans in 1982. With respect to the contemporary ELECTRE methods (ELECTRE III and IV) they brought at the same time more flexible preference modeling capabilities and a greater ease of use.
From the middle of the eighties the development of powerful interactive sensitivity analysis tools has been central to the evolution of the PROMETHEE methods. More specially the weighing of the criteria is known to play a major role in MCDA. It is thus essential for decision makers to be able to see to what extent changes of the weights of the criteria will impact the rankings provided by a multicriteria method. The PROMETHEE methods include several unique tools for this purpose such as the weight stability intervals and the Walking Weights interactive procedure.
In 1989 the introduction of GAIA added a descriptive complement to the PROMETHEE rankings. A graphical representation of the multicriteria problem enables the decision maker to better understand the available choices and the necessary compromises he or she will have to make to achieve a best decision. GAIA can also be used to see the impact of the criteria weights on the PROMETHEE rankings.
GDSS (group decision support system) extensions of PROMETHEE and GAIA have also been developed and integrated in the Visual PROMETHEE Software. They enable to compare the points of view of different decision-makers, to analyze conflicts between decision-makers and to generate consensus decisions.