This paper scrutinizes the increasing trend of using international large-scale assessment (ILSA) data for causal inferences in educational research, arguing that such inferences are often tenuous. We explore the complexities of causality within ILSAs, highlighting the methodological constraints that challenge the validity of causal claims derived from these datasets. The analysis begins with an overview of causality in relation to ILSAs, followed by an examination of randomized control trials and quasi-experimental designs. We juxtapose two quasi-experimental studies demonstrating potential against three studies using ILSA data, revealing significant limitations in causal inference. The discussion addresses the ethical and epistemological challenges in applying quasi-experimental designs to ILSAs, emphasizing the difficulty in achieving robust causal inference. The paper concludes by suggesting a framework for critically evaluating quasi-experimental designs using ILSAs, advocating for a cautious approach in employing these data for causal inferences. We call for a reevaluation of methodologies and conceptual frameworks in comparative education, underscoring the need for a multifaceted approach that combines statistical rigor with an understanding of educational contexts and theoretical foundations.