Micro-meso-macro: la social network analysis come insieme di tradizioni e programmi di ricerca.

The article analyses first the disciplinary and epistemological contexts of SNA; after, it compares the different theoretical approaches referable to SNA: the structural, the formalist, and the interactionist one. Then, two main methodological approaches are being compared: the “hard SNA” and the “soft SNA”, the first one – typical of the micro-analysis -- which considers the relational structure as the goal of research; the second one, which uses relational data as a tool for the theory building at the meso and macro levels. Further, SNA is proposed as an interdisciplinary and multi-purpose way-out from the theoretical dualism holism vs. individualism, particularly according to the structural interactionist approach. Finally, the four different explicative theories integrated in SNA (the theory of weak ties, the theory of the structural holes, the theory of clusterness, and the theory of relational coordination) are discussed as middle-range theories.