In recent years, education systems internationally have been encouraging data use initiatives with the aim of improving student learning through data-driven decision making (DDDM) (Means, Chen, DeBarger & Padilla, 2011). The use of student assessment data in particular has been promoted to guide teaching practices and progress student learning (Datnow & Hubbard, 2016; Hamilton et al., 2009). Despite this, the adoption of data use practices by New South Wales classroom teachers has been slow. A review conducted for this study on current DDDM models emphasised that recent research endeavours tend to focus on the later stages of data use, such as decision-making skills and targeted instruction. However, the activities that precede the ability to utilise data are not well understood. Targeting outcomes without understanding the context or procedural mechanisms that produce them yields constrained insight into how to support and enhance teachers’ data use practices. Consequently, this study qualitatively examined a core foundational activity that affects teachers’ use of student assessment data, referred to as assessment data collection (ADC) practices. The study specifically examined how New South Wales teachers gather and store student assessment data, which occurs after the delivery of the assessment but before the analysis of the resulting data. This presentation reports on the exploratory multiple case study design utilised, and the thematic analysis and cross case synthesis of results that mapped prominent existing ADC processes together with the salient factors influencing these processes. This enhanced insight into current practices provides a foundation that guides fit-for-purpose change initiatives to foster and augment data use in the classroom.