Aim: The aim of this paper is to describe how the Invitational Theory were used to frame each of the phases of this sequential mixed methods study to provide valuable insights to the failure to fail phenomenon. Background: The assessment of student nurses in clinical courses in undergraduate programmes remains problematic, with some students passing clinical courses when they do not meet standards for practice – failure to fail. Failure to fail is the allocation of passing grades to students who do not meet standards for practice. An understanding of assessors’ experiences is central to unravelling the complexities surrounding the phenomenon of failure to fail. Traditionally, such inquiry has been specific and narrow. The Invitational Theory is offered as a comprehensive approach to provide insights and understanding into the complex phenomenon of failure to fail. Design: The five domains of the Invitational Theory; people, processes, programmes, policies and places, were used to inform this sequential exploratory mixed methods study. Methodology: Phase 1 consisted of an integrative literature review. Phase 2 involved interviews and focus groups with tertiary assessors involved in assessment of students in clinical courses. Phase 3 involved the development, testing and piloting of a survey with tertiary and industry assessors. Phase 4 consisted of a meta-integration of all phases of the study. Results: Key findings of the synthesis of these study phases demonstrated that the domains of the Invitational Theory enable a comprehensive and unique viewpoint of assessment during clinical practicum. All five domains of the Invitational Theory were evident throughout this study and provided unique insights into failure to fail. This research has identified the theoretical underpinnings of the Invitational Theory and its application can be of value in the area of nurse education and specifically assessments. Conclusion: The Invitational Theory domains provides a comprehensive and unique viewpoint of assessment of nursing students and contributed to the emerging body of literature regarding failure to fail. How the theoretical framework facilitates the understanding of failure to fail is described in this paper.