mechanism" is frequently encountered in the social science literature, but there is considerable confusion about the exact meaning of the term. The article begins by addressing the main conceptual issues. Use of this term is the hallmark of an approach that is critical of the explanatory deficits of correlational analysis and of the covering-law model, advocating instead the causal reconstruction of the processes that account for given macro-phenomena. The term "social mechanisms" should be used to refer to recurrent processes generating (...) a specific kind of outcome. Explanation of social macro-phenomena by mechanisms typically involves causal regression to lower-level elements, as stipulated by methodological individualism. While there exist a good many mechanism models to explain emergent effects of collective behavior, we lack a similarly systematic treatment of generative mechanisms in which institutions and specific kinds of structural configurations play the decisive role. Key Words: causal regression • correlational analysis • emergent effects • micro-macro processes • social mechanisms • structural determinants. (shrink)