Assessment as part of the enacted curriculum is underscored by the professional judgement of the lecturer, who decides on the body of knowledge that should be learned. A vacuum exists in understanding how the practice of assessment is shaped by the lecturer and between the social groups within departments and the academic institution at large, as well as the transformational policies within the higher education space. Assessment is a key driver to advance a socially just medical curriculum, especially in the context of the legacy of colonialism and apartheid in South Africa (SA). Using the existing body of knowledge about assessment from the global North, without re-contextualising it for a South African context, has led to decontextualised practices that treat assessment as a one-size- fits-all phenomenon. In this study, the influences on lecturers' assessment practices within an undergraduate medical programme were explored. Enabled by the critical realist paradigm, this study sought to illuminate the structural and cultural mechanisms that enabled or constrained medical lecturers' assessment practice. Margaret Archer's social realist theory was used to theorise assessment by using analytical dualism and giving powers and properties to structure, culture, and agency independently, as a way to explore and critically analyse the mechanisms that condition lecturers' assessment practice. Using collective case study design, individual interviews were conducted, and the assessment documentation was gathered from six lecturers in the medical programme at one institution. Narratives from two pre-clinical and four clinical lecturers and the assessment documentation were analysed to provide a way to better understand the influences guiding lecturers' assessment practices. More importantly, how lecturers exercise their personal emergent powers and properties to enact assessment was examined. The analysis shows that the interplay of the systemic mechanisms that emerged in the assessment practice of lecturers set up complex choices for the transformation of assessment. In the context of historic transformation imperatives and the student protests, the study's findings show that lecturers exercised their agential powers and properties to elaborate the ideas and theories towards conventional evidence-based assessment practices that were predominantly teacher-led. Lecturers relied on their own experience of assessment, learning about assessment formally in education programmes and informally through colleagues and courses. However, the systemic constraints such as timetabling, limited integration, disciplinary power, insufficient human, and financial resources to innovate and transform assessment, encouraged choices that were ill aligned to inclusive assessment practices. The support of lecturers' assessment endeavours is desperately needed at all levels, national, institutional, departmental and programmatic, to transform assessment practice. The findings highlight the need for re-evaluation of current interventions to elevate the ontological and epistemological issues. The results have implications for the design of staff development activities and the way assessment is designed, created, and administered
