Textbooks and considerable normative research implicitly assume that Information Systems Development Methodologies (ISDMs) are used and are useful. Evidence suggests that methodology use is problematic. This work-in-progress paper reports on an in-depth case study seeking to identify rational and political roles leading to why a methodology is used in an IS department within a large Australian bank. Guided by a framework to study the use of methods the analysis demonstrates the plausibility of a portion of the framework thereby contributing to a phase of the theory building process.