On Defining Chart Types Boundaries
2026-08-03 • Human-Computer Interaction
Human-Computer Interaction
AI summaryⓘ
The authors explored what exactly defines a Gantt chart because existing definitions varied and caused confusion. They figured out how to separate core, essential features of a chart from flexible ones, helping them understand how different chart types relate and differ. By studying these boundaries, they created useful tools and vocabulary for defining chart types, including Gantt charts, and showed how research choices affect what counts as a type of chart. Their work helps researchers be clearer about their definitions and assumptions when studying or designing charts.
Gantt chartchart design spacechart taxonomyfeature entanglementboundary workgraphical perceptionchart grammarvisualization researchradar charttable cartogram
Authors
Chang Han, Andrew Mcnutt, Katherine E. Isaacs
Abstract
What makes a Gantt chart? This question proved unexpectedly difficult to answer when we set out to build a design space for Gantt charts. Existing definitions, each shaped by their respective research goals, made different scope choices that we could not directly reconcile. We reasoned about what should and should not count as a Gantt chart, developing concepts and tools along the way. We distinguish features that are essential to a chart type's identity from those that can vary, and use these distinctions to map how chart types relate through what they share and lack. Applying these ideas to Gantt charts, radar charts, and table cartograms, we produce key insights on what boundary work reveals: definitions diverge for functional reasons, drawing boundaries exposes hidden structure in descriptive vocabulary such as feature entanglements, and scope choices shape how far findings can generalize. We came to understand that there is not a definitive answer, but that working through the question produced a functional definition that guided the design space we originally set out to build. Additionally, we present vocabulary and tools for reasoning about chart type boundaries and surfacing these boundary decisions, alongside a documented Gantt chart design space. Our broader reflection is that scope choices in chart-type-centered research---which determine what design spaces include, what grammars generate, and what perceptual studies measure---are research decisions worth making visible.