Narrative and Sequence

Source: Visual Explanations: Images and Quantities, Evidence and Narrative (VE), Edward R. Tufte, Graphics Press, Cheshire, Connecticut, 1997. Chapters 1–6.

Overview

Visual explanations explain why and how, not just what — they depict process, causality, motion, and change. Two failures recur and both are epistemic, not aesthetic: dequantification (images stripped of the scales, labels, and orientation that answer how many / how often / where / how much / at what rate) and disinformation design (display tactics, borrowed knowingly or not from magicians, that conceal rather than reveal). The governing standard is the same one a scientist uses: show all the relevant data, put the causally meaningful variable on the correct axis, make comparisons within the eyespan, and never drop the cases that fail to confirm the pattern. Tufte's most consequential case is the Challenger launch decision — the 13 charts faxed to NASA the night before never put temperature, the causal variable, on an axis and left out 92% of the relevant temperature data (p.43); seven people died. Sequence and narrative design carry life-and-death weight.

"People can see more clearly if they have the right idea." — Tufte, Visual Explanations, p.107

§1. Images and Quantities — The Dequantification Problem (Ch.1, pp.13–26)

The foundational theme of the book: scientific and artistic images routinely shed their quantitative scaffolding. A picture without scale, orientation, and labels cannot answer the analytic questions — How many? How often? Where? How much? At what rate? Restoring those answers is "quantifying" the image.

The three quantification techniques (p.13): Tufte names the ways quantity attaches to an image — direct labels (words and numbers written straight onto the picture), encodings (values translated into visual properties such as tone or symbol), and self-representing scales (objects of known size placed inside the scene so the image measures itself — the opening example is Koudelka's photograph of a wristwatch held into an empty street, timestamping the scene). Every Ch.1 example below is a diagnosis against this triad.