Structure as cause and representation: Implications of descriptivist inference for structural modeling across multiple levels of analysis

What does a structural model reflect? Different answers to this question implicitly underlie different nosological paradigms. Traditionally, structural analysis has been seen as a process of identifying true or causative values, states, or conditions. This paradigm has faced mounting challenges, however, as psychopathology theory and research has come to encompass different levels of analysis, with concomitant questions about what constructs are most "correct." Here, we discuss an alternative descriptivist paradigm, in which models are seen as the process of identifying optimally parsimonious, generalizable representations of observations. This paradigm allows for an integration of theoretical and methodological approaches that are often seen in mutual opposition, and recasts traditional measurement and structural models in a new light. In this article, we explain the descriptivist perspective, illustrating important concepts using empirical examples from the Human Connectome Project and this issue. We address structural theory within the context of varying levels of analysis, demonstrating how the descriptivist approach can elucidate the nature of hierarchical features and provide a framework for empirically delineating psychopathology structure.