In the tradition of Swalesian genre theory, this manuscript explores the rhetorical composition of research article Methods sections through a top-down analysis of a corpus of nine hundred texts representative of thirty academic fields. The analysis resulted in a comprehensive cross-disciplinary model, called Demonstrating Rigour and Credibility (DRaC). The model contains three moves and sixteen steps, which are defined in terms of functional and content realizations. DRaC further served as the analytic framework for corpus annotation. Manually annotated corpus data revealed the moves and steps with high distributional prominence as well as those that are not frequent but occur consistently within and across disciplines. Visualizations of individual texts in a sample of disciplines demonstrated inter-disciplinary and intra-disciplinary patterns and variation in move sequencing. Additionally, algorithmic analysis of the annotated corpus showed that soft and hard sciences form clusters based on their use of DRaC steps, providing a deeper understanding of how shared conventions of rhetorical composition distinguish cross-disciplinary similarities in Methods discourse. The findings lend themselves to application in genre writing pedagogy and, more broadly, hold implications for theories of social and cognitive genres.