CS373 - Captions That Work
Captions That Work
Narrative Captions for Figures in Technical Papers
Introduction
When writing technical papers and including diagrams, charts, tables, or other figures, using a multi-sentence, stand-alone caption that creates a mini-story is a highly effective technique. This approach is supported by best practices in scientific communication and has proven benefits.
What the Literature Says
- “Extended Captions” or “Narrative Captions”:
- Style guides refer to this as extended or narrative captions, providing context, explanation, and even interpretation.
- Tufte and Visual Explanation:
- Edward Tufte, in The Visual Display of Quantitative Information and Beautiful Evidence, advocates for rich explanatory content integrated with visuals.
- Scientific Style and Format (CSE Manual):
- Recommends that figure legends be complete enough that readers can understand figures without the main text.
- Writing Science (Joshua Schimel):
- Advises using figure captions to “tell the story of the figure” with clarity and narrative.
- Nature & Science Journal Standards:
- Encourage multi-sentence legends explaining what’s shown, how it was generated, and its meaning.
Why It Works (And Why Others Use It)
- Enhances Skimmability: Readers often skim papers by jumping from figure to figure.
- Improves Accessibility: Helps both novice and expert readers.
- Reinforces Key Points: Boosts retention and understanding.
- Facilitates Repurposing: Easier reuse in talks, reports, or education.
Tips for Writing Strong Stand-Alone Captions
- Start with context: What is being shown and why?
- Describe the method or metric: How was the data obtained or calculated?
- Interpret the result: What should the reader take away?
- Reference if needed: Optionally tie to the main text for deeper details.
Example: Short vs. Long Captions
Example Figure
Short Caption
Figure 1. Growth rates of Strain A and Strain B at different temperatures.
Long, Narrative Caption
Figure 1. Growth rates of Strain A and Strain B across a range of temperatures from 10°C to 40°C. Data were collected in triplicate under controlled laboratory conditions. Strain A demonstrates optimal growth near 30°C, after which its growth rate declines sharply, likely due to heat sensitivity. In contrast, Strain B maintains a steadier growth rate across the entire range, suggesting greater thermal resilience. These differences highlight the importance of temperature adaptation mechanisms in bacterial survival and have implications for strain selection in industrial fermentation processes. Error bars represent standard deviation across replicates.
Side-by-Side Comparison
| Feature | Short Caption | Long Narrative Caption |
|---|---|---|
| Provides Context | ❌ No | ✅ Yes |
| Describes Key Trends | ❌ No | ✅ Yes |
| Suggests Interpretation | ❌ No | ✅ Yes |
| Standalone Understanding | ❌ Requires main text | ✅ Reader understands figure alone |
Scaling the Approach by Audience Type
1. Journal Article
Goal: Detailed and precise.
Example:
Figure 1. Growth rates of Strain A and Strain B across temperatures from 10°C to 40°C, measured in triplicate under controlled laboratory conditions. Strain A shows a growth peak at 30°C, declining rapidly above this temperature, suggesting a narrow thermal tolerance window. Strain B maintains stable growth across the full range, consistent with broad thermal adaptation mechanisms. Error bars represent standard deviation. These findings may inform the selection of strains for thermally variable industrial applications.
2. Technical Report
Goal: Comprehensive documentation.
Example:
Figure 1. Growth profiles of bacterial strains A and B across a temperature gradient (10°C–40°C) are shown. Cultures were incubated in triplicate, with growth monitored via optical density at 600 nm. Strain A demonstrated maximal growth at 30°C, with significant inhibition beyond this point, consistent with mesophilic behavior. In contrast, Strain B exhibited constant growth, indicating broad thermal tolerance. These results suggest Strain B is better suited for variable-temperature bio-industrial processes. Standard deviations are depicted as error bars.
3. Grant Proposal
Goal: Highlight significance quickly.
Example:
Figure 1. Comparison of growth rates for Strain A and Strain B reveals key differences in thermal resilience. Strain A thrives at 30°C but declines sharply thereafter, while Strain B maintains steady growth. This robustness suggests Strain B could enable reliable bio-production in variable temperature environments.
4. Conference Presentation
Goal: Instant comprehension.
Example:
Figure 1. Strain A grows best at 30°C but declines sharply at higher temps. Strain B grows steadily across a wide range. Strain B’s thermal tolerance supports its use in variable-temperature bio-industrial processes.
Summary Table
| Audience Type | Key Focus | Caption Length | Tone |
|---|---|---|---|
| Journal Article | Accuracy, replicability | Medium (~4–6 sentences) | Formal, technical |
| Technical Report | Completeness, documentation | Long (~5–10 sentences) | Formal, readable |
| Grant Proposal | Significance, impact | Medium (~3–5 sentences) | Narrative, persuasive |
| Conference Presentation | Fast comprehension | Short (~2–3 sentences) | Crisp, conversational |
Final Note
Good figure legends:
- Give sufficient background without redundancy.
- Focus attention on important patterns or anomalies.
- Relate explicitly to the research question or hypothesis.
References
- Tufte, E. R. (2001). The Visual Display of Quantitative Information.
- Schimel, J. (2012). Writing Science: How to Write Papers That Get Cited and Proposals That Get Funded.
- Day, R. A., & Gastel, B. (2011). How to Write and Publish a Scientific Paper.
- CSE Manual: Scientific Style and Format (8th ed.).