references/foundations/theory-and-principles.md

# Theory and Principles

## What Problem This Solves

This reference gives the plugin a common design vocabulary so different skills reason from the same foundations instead of reinventing chart advice ad hoc.

## When to Use It

Use this when choosing a chart, critiquing a visual, explaining why a view works, or deciding whether to simplify, annotate, facet, or restructure a figure.

## Key Takeaways

- Tufte-style guidance favors evidence-rich visuals, direct integration of words and graphics, and restraint toward decoration.
- Bertin-style thinking reminds you that position, size, shape, hue, value, texture, orientation, and motion are not interchangeable.
- Cleveland and McGill's ordering of visual encodings is a practical reason to favor bars, dots, and aligned scales over area- and angle-heavy alternatives.
- Tukey-style exploration means plotting early and preserving surprising structure long enough to understand it before collapsing it into summary.
- Munzner's nested model helps separate domain task, data abstraction, encoding design, and implementation choice.
- Shneiderman's mantra is still a strong interaction default for analytical surfaces: overview first, zoom and filter, then details on demand.

## Common Mistakes

- Treating famous names as slogans rather than working decision frameworks.
- Using "minimalism" to justify removing necessary labels, context, or explanations.
- Copying a chart form from another domain without checking whether the task and comparison structure match.

## Adjacent Skills

- `../../skills/visualization-strategy-and-critique/SKILL.md`
- `../../skills/statistical-and-uncertainty-visualization/SKILL.md`
- `../../skills/accessibility-and-inclusive-visualization/SKILL.md`

## Source Links

- [Edward Tufte books](https://www.edwardtufte.com/books/)
- [The Visual Display of Quantitative Information](https://www.edwardtufte.com/book/the-visual-display-of-quantitative-information/)
- [Envisioning Information](https://www.edwardtufte.com/book/envisioning-information/)
- [Visual Explanations](https://www.edwardtufte.com/book/visual-explanations-images-and-quantities-evidence-and-narrative/)
- [Beautiful Evidence](https://www.edwardtufte.com/book/beautiful-evidence/)
- [Tamara Munzner's Nested Model](https://www.cs.ubc.ca/labs/imager/tr/2009/NestedModel/)
- [Visualization Analysis and Design](https://mitpressbookstore.mit.edu/book/9781466508910)
- [The Eyes Have It](https://drum.lib.umd.edu/items/95af2c8e-0d1e-48cc-a954-c9301d7bf618)