Data-driven decision-making (DDDM) refers to the process of using data to inform educational decisions. Due to DDDM's positive effects on student achievement and the pressure for educational accountability, DDDM has become a recent focus of numerous educational policies. However, few teachers fully utilize DDDM. While, broadly, DDDM may use various types of data to make different types of decisions, the current study focuses on the use of formative assessment data to guide instructional adaptations. This study serves as an elicitation study to explore teachers' perceptions of DDDM, illuminating both facilitating and inhibitory factors affecting assessment practices. The Theory of Planned Behavior was applied as a theoretical framework, which suggests that individuals' behaviors can be explained by their attitudes, perceptions of social norms, and perceived behavioral control. Nine elementary teachers from Indiana (the USA) participated in focus groups. The findings indicated teachers (a) had positive thoughts (e.g., helpful) but negative feelings (e.g., stressful) about DDDM, (b) were highly impacted by their schools' culture of assessment, and (c) had mixed perceptions about their capacity and autonomy in conducting DDDM. These findings will be used to develop a quantitative instrument for future research. Furthermore, these findings can be used to support educational leaders' efforts to provide better professional development and to facilitate more supportive school environments to ensure teachers can successfully implement DDDM practices.