To perform evaluation and improvement activities, the definition of a goal is usually the starting point of a project. Typically, a goal contains the statement of a purpose. In the Software Engineering literature, different evaluation purposes such as to understand, monitor, predict, improve, control, compare and selection are mentioned. These purposes share distinctive and common aspects as we discuss in the present work. A categorization that helps a better understanding of them is also proposed. Additionally, in order to reach the purpose of a goal, a strategy should be selected. We have envisioned different strategies for different purposes. Basically, a strategy describes a course of action by means of the specification of activities and methods. In order to analyze the applicability of a strategy, we illustrate the strategy for the compare and adopt purpose for adopting strengths in a new app comparing four social network applications.