Goal models

One important step in requirements elicitation is the identification of business goals [1]. This step can be ignored if not needed, however in most cases since business people are the driving force for software projects, their goals needs to be accommodated and put in mind when requirements are elicited. Goal modeling is a common techniques to elicit business goals. Goals can be break down into different levels. Typically, the higher level of goals would be more abstract and general, while lower level of goals would be more specific. In other words, the more levels you break goals, the more details you get. Goals can be conflicted with each other, thus once goals are collected it should be followed by a refinement step where those nonfunctional requirements can bring some important issues in regard to the system requirements. Goal model can be as simple or as complex as it needed. No standard for the level of details, it just the current need drive the modeling.
Another approach to use goal model is to use it along with quality assessment methods (QAMs). QAMs are used to identify identify the quality goals that meets business goals. The goal behind using QAMs with goals models is to make sure that important nonfunctional requirements are not missed. Also, to make sure that nonfunctional requirements can be tested.

The following figure contain a simple example of a simple goal model