Design Considerations for Drill-down Charts

Frequency-based statistical charts are the most widespread visualizations and the preferred of Infovis novices. They are important in depicting categorical data and providing data abstraction on large datasets. The drill down feature enables better visual scaling by allowing navigation through aggregation hierarchies. In this paper we discuss design considerations that impact on the usability in drill down charts. We develop a tool based on pie chart in order to illustrate the discussion. Moreover, we suggest visual representations and an interaction model. Finally, we provide evidence on the benefit of using such techniques for visual analysis of categorical data through a short usability study.