Goal modeling is applied to early and late requirement models in order to refine them and to elicit new dependencies. During architectural design, it contributes to motivate the first decomposition of the system-to-be actors into a set of sub-actors.

Goal modeling rests on the analysis of an actor goals, conducted from the point of view of the actor, by using three basic reasoning techniques: means-end analysis, contribution analysis, and AND/OR decomposition.

In particular, means-end analysis aims at identifying plans, resources and softgoals that provide means for achieving a goal.

Contribution analysis identifies goals that can contribute positively or negatively in the fulfillment of the goal to be analyzed. In a sense, it can be considered as an extension of means-end analysis, with goals as means.

AND/ OR decomposition-combines AND and OR decompositions of a root goal into sub-goals, modeling a finer goal structure.

 See The Tropos metamodel and its use for more information.