There are dissonances between educators' aspirations for assessment design and actual assessment implementation in higher education. Understanding how assessment is designed "on the ground" can assist in resolving this tension. Thirty-three Australian university educators from a mix of disciplines and institutions were interviewed. A thematic analysis of the transcripts indicated that assessment design begins as a response to an "impetus for change". The design process itself was shaped by "environmental influences", which are the circumstances surrounding the assessment design, and "professional influences", which are those factors that the educators themselves bring to the process. A range of activities or tasks were undertaken, including those which were "essential" to all assessment design, those more "selective" activities which educators chose to optimise the assessment process in particular ways and "meta-design" processes which educators used to dynamically respond to environmental influences. The qualitative description indicates the complex social nature of interwoven personal and environmental influences on assessment design and the value of an explicit and strategic ways of thinking within the constraints and affordances of a local environment. This suggests that focussing on relational forms of professional development that develops strategic approaches to assessment may be beneficial. The role of disciplinary approaches may be significant and remains an area for future research.