The subject of this article is the assessment of the effectiveness of medical procedures or interventions. In its first part I compare the different meanings that the term effectiveness assumes in the context of assessing medical interventions, including the definition of the concept of consequential effectiveness, i.e. efficiency in achieving a certain objective of recognized value, distinguishing it from purely instrumental efficiency, i.e. effectiveness in achieving any goal, and from "cost-effectiveness" or economic efficiency. Next, I discuss various directions of relativization that allow for, and largely assume, assessments of the effectiveness of medical interventions, primarily considering the purpose, which serves as their point of reference. In the third part, I emphasize the different character of assessments of the effectiveness of medical procedures depending on whether they relate to the final or only to the indirect purpose of a given procedure. Finally, I consider the validity of the popular opposition of effectiveness and efficiency, and egalitarian fairness or justice (equity) in relation to health care procedures.