ποΈ Week 05 - - Proportions & Nested Data
This week tackles one of the most common yet contentious topics in data visualization: showing proportions and compositional data. Students will engage with the great pie chart debate, learning when these polarizing visualizations actually work andβmore importantlyβwhen they fail spectacularly. Beyond simple proportions, weβll explore the challenge of visualizing hierarchical and nested data, where categories contain subcategories that themselves may contain further divisions.
The first half of the week examines visualizations for parts of a whole. Weβll critically evaluate pie charts, donut charts, stacked bars, and side-by-side bars, understanding the perceptual strengths and weaknesses of each approach. Students will learn that the βbestβ visualization depends on the specific comparison task: pie charts can work for showing a dominant majority, but stacked bars excel at comparing compositions across groups, while side-by-side bars make precise category-to-category comparisons easier. The goal is to develop judgment about when each tool is appropriate rather than following rigid rules.
The second half levels up to nested proportions and hierarchical data. Students will learn to create treemaps for space-efficient hierarchical displays, mosaic plots for examining relationships between categorical variables, and sunburst charts for elegant circular hierarchies. Weβll also introduce parallel sets for visualizing flows between categories. Thursdayβs Tableau tutorial provides hands-on practice building these more complex visualizations, with special focus on creating hierarchies, implementing drill-down functionality, and using color strategically to reveal patterns in multi-level data structures.
π¨βπ« Lecture Slides Tuesday
Either click on the slide area below or click here to view it in fullscreen. Use your keypad to navigate the slides.
π¨βπ« Lecture Slides Thursday
Either click on the slide area below or click here to view it in fullscreen. Use your keypad to navigate the slides.