• Hyeon Jeon, Seoul National University
• Jeongin Park, Seoul National University
• Sungbok Shin, Sogang University
• Jinwook Seo, Seoul National University

Misuses of t-SNE and UMAP in visual analytics have become increasingly common. For example, although t-SNE and UMAP projections often do not faithfully reflect the original distances between clusters, practitioners frequently use them to investigate inter-cluster relationships. We investigate why this misuse occurs, and discuss methods to prevent it. To that end, we first review 136 papers to verify the prevalence of the misuse. We then interview researchers who have used dimensionality reduction (DR) to understand why such misuse occurs. Finally, we interview DR experts to examine why previous efforts failed to address the misuse. We find that the misuse of t-SNE and UMAP stems primarily from limited DR literacy among practitioners, and that existing attempts to address this issue—mostly based on academic papers—have been ineffective. Based on these insights, we discuss potential future research directions to mitigate the misuse.