Private funding tripled in two years , but government still anchors the base Figure 67.1 , Private funding tripled , government still anchors the base

A stacked bar chart divides each bar into sequential segments representing subcategories of a total. Each bar's full height encodes the total value; each segment's height encodes its contribution. Unlike a grouped bar chart , which places subcategory bars side-by-side , stacking preserves the total while showing composition. The two variants serve different analytical goals.

The stacked chart's structural flaw is that only the bottom segment sits on a common zero baseline. Every other segment has a different starting point in every bar, making direct comparison of non-bottom segments perceptually unreliable. The eye cannot accurately judge if the "Private Foundation" segment in 2022 is larger or smaller than in 2023 without reading the tooltip. This is why segment order matters: put the category most important to compare at the bottom.

Use the absolute view when the total matters , when the viewer needs to know that overall investment tripled, not just that composition shifted. The total bar height carries real information that the 100 percent view discards. Use the 100 percent view when you want to isolate compositional change from volume change. In the 100 percent view, Government's declining share is visible even though its absolute dollar value grew every year. Both facts are true; the chart choice determines which fact is foregrounded.

If comparing subcategory values across bars is the primary task, a stacked bar chart will always underperform. The correct alternatives: a grouped bar chart (each subcategory gets its own bar, enabling direct comparison), a small multiples line chart (one panel per category showing its trend), or a slope chart (comparing start and end points without intermediate clutter).

Paste this into Claude Code to generate a working version of this chart, plus its data file. The result will not be a perfect replica , the goal is that the reader can run the prompt, get a chart of this type, and read its source. Generate a complete, self-contained stacked bar in D3 v7. Two files:

The ideas in this chapter didn't appear from nowhere. Heinz von Foerster was a cyberneticist who pushed information visualization into circular and stacked forms during the 1960s , and led the Biological Computer Laboratory at Illinois, an early home of second-order cybernetics and visual reasoning about complex systems. Heinz von Foerster, circa 1970. AI-generated portrait based on a public domain photograph (Wikimedia Commons).

The ideas in this chapter didn't appear from nowhere. Heinz von Foerster was a cyberneticist who pushed information visualization into circular and stacked forms during the 1960s , and led the Biological Computer Laboratory at Illinois, an early home of second-order cybernetics and visual reasoning about complex systems. Heinz von Foerster, circa 1970. AI-generated portrait based on a public domain photograph (Wikimedia Commons).