Association, cause, and causal association. Revision 2: playing the changes

The motivation to examine associations between single or multiple factors and the occurrence or progression of health events is, arguably, driven by the desire to better the health of individuals or to affect the public health, in general. As such the enterprise is equally at home in the basic science laboratory as it is observing population-level phenomena and chronicling their occurrences. The approaches to establish “causal criteria” to evaluate such associations have in large part been pragmatic rather than philosophical. However, philosophical logic is woven into the pragmatic fabric of the task of characterizing observed associations as potentially “causal” ones. In this revision of a chapter in the previous edition of this textbook, we now provide additional description of some newer techniques, theories, and occasional controversies regarding the study of causal inference.