Causal inference in epidemiological research

Sammanfattning: Traditionally, statistics has been viewed as the branch of science which deals with association. Many epidemiological research questions, however, are concerned with causation, not association. In this thesis we develop novel statistical methodology to address four epidemiological problems properly, from a causal inference point of view. We show, that for these four problems, our methods offer an attractive alternative to the `standard' methodology, which may not yield the desired (causal) inference.