Maintaining academic integrity is an area of major importance for today's institutions of higher learning. Despite universities having in place academic integrity policies and procedures, findings from semi-structured interviews with 26 academics from four, public Western Australian universities suggest that responses to incidences of student plagiarism are inconsistent and not aligned with the responses expected of them by their institution as set out in these institutional documents. Using thematic analysis, an SIA model is proposed which categorises the reasons for these inconsistencies under Student, Academic and Institutional factors. It suggests that if academics prioritise the student and themselves, their responses are more likely to be inconsistent and not aligned with the responses expected from them by their institution. Recommendations to help develop a shared understanding of plagiarism include online, academic integrity modules for all staff. This shared understanding will lead to more consistent and aligned responses which in turn will help maintain the reputation of the institution and the integrity of its awards.