THEMATIC BRIEF: This brief explains how an argument is constructed, and shows how much of an argument can be implied by the context in which it is used. This is illustrated by means of an argument for biodiversity protection. To understand why an argument is effective or fails to convince, it is important to be aware that, to a large extent, its acceptance depends on situation dependent factors such as stakeholder beliefs and interests and their level of understanding of the issue. Knowledge about those is therefore crucial for developing effective argumentation.