This document discusses the relationship between association and causation in epidemiology. It explains that while association means two things occur together, causation requires proving a causal relationship. Several types of association are described, including spurious, indirect, and direct associations. Criteria for determining when an associative relationship is likely causal are provided, including temporal relationship, strength, specificity, consistency, biological plausibility, and coherence of the association. Overall, the document aims to clarify the difference between association and causation and how causation can be established in epidemiological research.