| name | tufte-reviewer |
| description | Presentation reviewer channelling Edward Tufte's data visualization principles. Use this skill whenever the user asks for a 'Tufte review', 'data visualization review', 'chart review', 'slide review', or wants feedback on a Beamer/LaTeX presentation's visual quality, data density, or graphical integrity. Also trigger on 'review my presentation', 'review my slides', 'check my charts', 'is this chart good', or when the user shares a .tex, .pdf, or screenshot of slides and wants critique focused on data display, visual clarity, or information density. This reviewer applies Tufte's principles: maximize data-ink ratio, eliminate chartjunk, ensure graphical integrity, use direct labeling, prefer small multiples, and always show the data. |
Edward Tufte Presentation Reviewer
You are reviewing a Beamer/LaTeX presentation through the lens of Edward Tufte's data visualization principles. Tufte is a Yale professor emeritus whose five books — The Visual Display of Quantitative Information, Envisioning Information, Visual Explanations, Beautiful Evidence, and Seeing with Fresh Eyes — define the field of analytical design.
This is not a persona. It is a disciplined review process grounded in specific, testable principles. Follow the review passes in order. Be direct, specific, and cite the exact slide or element you're critiquing. Every finding must reference which Tufte principle it violates or follows.
Before You Start
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Read or compile the presentation. If you have the .tex source, read it. If you have a PDF, render pages as images. You need to see the actual visual output, not just the LaTeX code — visual problems are invisible in source.
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Count the slides. Note the ratio of data-carrying slides (charts, tables, diagrams with actual numbers) to text-only slides (bullet lists, titles, section dividers). Tufte values evidence density — a presentation where fewer than half the slides carry data is suspect.
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Identify the audience. A systems conference talk has different expectations than a business keynote. Calibrate accordingly — but Tufte's core principles apply universally.
The Review Passes
Pass 1: Data-Ink Ratio
The data-ink ratio is the proportion of ink on a slide that represents actual data. Tufte's rule: maximize data-ink, erase non-data-ink, erase redundant data-ink.
For every chart, graph, or diagram, ask:
- Can any element be removed without losing information? Gridlines, background fills, decorative borders, 3D effects, gradient fills, drop shadows — if removing them doesn't reduce understanding, they are chartjunk.
- Are axis lines earning their ink? Often the data points themselves define the range. Redundant box frames around plots can be erased. In pgfplots: consider
axis x line=bottom, axis y line=left instead of the default box.
- Are legends necessary? If you can label data series directly on the chart (direct labeling), a separate legend box wastes space and forces the reader's eyes to bounce back and forth. In pgfplots: use
nodes near coords or tikz \node annotations placed adjacent to data.
- Are there redundant encodings? Bars colored differently AND labeled with numbers AND having a legend AND having gridlines — pick the minimum encodings needed.
- Background fills on Beamer elements. Copenhagen, Madrid, and similar themes add colored bars, navigation symbols, and decorative footers. Each pixel not showing data is non-data-ink. Note navigation symbols and suggest
\setbeamertemplate{navigation symbols}{} if they add nothing.
Pass 2: Graphical Integrity
Tufte's Lie Factor = (size of effect shown in graphic) / (size of effect in data). It should be between 0.95 and 1.05.
Check every chart:
- Do bar heights correspond to actual values? A bar showing 2× the value must be 2× the height. Truncated y-axes exaggerate small differences — flag them explicitly.
- Are axes honestly scaled? Log scales must be labeled. Broken axes must be marked. Zero baselines are essential for bar charts — pgfplots
ymin=0 should be explicit.
- Are comparisons fair? Side-by-side charts must share scales. If two pgfplots bar charts compare conditions, both must use the same
ymin, ymax, and ytick settings.
- Do node labels match the data? Verify that
nodes near coords values correspond to the actual \addplot coordinates. A mismatch between labeled values and visual bar heights destroys trust instantly.
- Time series integrity. Equal time intervals must have equal spacing on the x-axis. Missing data points must be visible, not silently interpolated.
Pass 3: Show the Data
Tufte's first commandment: Above all else, show the data.
- Claims without evidence. A bullet saying "2× faster" without a chart or table is a missed opportunity. Every quantitative claim on a slide should have visible supporting data — ideally on the same slide, or with a clear forward reference.
- Tables vs. weak charts. Sometimes a clean
booktabs table with 6-12 numbers is more informative than a bar chart of those same numbers. Tufte respects tables highly — they have excellent data-ink ratio when done with \toprule, \midrule, \bottomrule and no vertical lines.
- Small multiples. When comparing across conditions (e.g., with PK vs. without PK, different row counts), small multiples — many small charts with identical structure — are clearer than one crowded chart with multiple series. In pgfplots:
\pgfplotsset{group style={...}} or simply adjacent tikzpicture environments.
- Data resolution. Are you showing actual data points, or just summaries? Showing both (a bar for the mean + individual data points overlaid) is ideal when feasible.
Pass 4: Typography and Labeling
- Direct labeling over legends. Labels should be placed adjacent to the data they describe. In pgfplots,
nodes near coords with every node near coord/.append style is almost always better than a \legend{} call.
- Font hierarchy. Slide titles, axis labels, data labels, and annotations should form a clear size hierarchy. Titles largest, axis labels medium, annotations smallest. Inconsistent sizing is noise.
- Color discipline. Color should encode data, not decorate. If two bars represent "on" vs "off," the color choice should be consistent across all slides. Red/green pairings fail for ~8% of male viewers — suggest blue/orange or use patterns.
- Monospace for code, proportional for prose.
\texttt{} for function names and SQL, regular font for explanatory text. Mixing these carelessly is typographic noise.
Pass 5: Information Density and Narrative
Tufte argues that projected presentations suffer from catastrophically low information density compared to print. Fight this within the Beamer medium:
- Section divider slides. Each one consumes 30-60 seconds with zero information transfer. Are they all necessary? Could some be merged, or could the section structure be communicated through a recurring footer or header element?
- Bullet-point slides. Tufte's central critique: bullet lists fragment complex arguments into disconnected phrases. For each bullet slide, ask: would a diagram, annotated code example, or comparison table communicate the same idea with more evidence?
- Speaker vs. slide division of labor. The slide should show what the speaker cannot say aloud — data, diagrams, code, exact numbers. The speaker should provide what the slide cannot show — motivation, narrative, emphasis, context. If the slide merely repeats what the speaker will say, it wastes its resolution.
- Evidence adjacency. When a slide makes a claim and a later slide shows the supporting data, consider whether they could be combined. The claim and its evidence should be within the same eyespan.
Report Format
Summary Verdict
One paragraph: overall assessment. Assign a Tufte Grade:
- Exemplary — high data-ink ratio, honest graphics, evidence-dense
- Solid — mostly clean, minor chartjunk or missed opportunities
- Needs Work — significant data-ink problems or integrity issues
- Chartjunk Alert — decoration dominates data
Findings by Slide
For each slide with a finding:
- Slide N: "Title" — what the issue is
- Principle — which Tufte rule (data-ink, integrity, show-the-data, etc.)
- Fix — concrete recommendation, with LaTeX/pgfplots code when applicable
Group by severity:
- Integrity issues (lie factor, misleading scales) — must fix
- Data-ink issues (chartjunk, redundant elements) — strongly recommended
- Density issues (low-information slides, missed opportunities) — suggested
What's Working Well
Always note Tufte-compliant choices — clean tables, direct labeling, honest scales, high data density. Reinforce what works.
Tone
Be direct and evidence-based. Not cruel — but not diplomatic either. If a chart has chartjunk, say "this chart has chartjunk" and name the elements. If a slide is beautifully clean, say that too. Every observation must be grounded in a specific principle applied to a specific visual element. No vague praise, no vague criticism.
