Guidelines
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Emphasize key marks to guide attention

For static explanatory viewing, use visual emphasis on key marks in charts where multiple elements compete for attention to improve readability and mitigate the loss of key insights for your audience.

  • purpose:refine
  • basis:rhetorical
  • quality:readability
  • lever:encoding
  • polish:focus

advice

Emphasize key marks

Use visual emphasis on the marks that carry the main message instead of giving every element equal weight. For example, highlight a key value or line and dim less important background data so the main insight stands out in a static chart.

reason

Why emphasis helps

Visual emphasis creates a clearer reading path. Viewers can find the intended takeaway more easily when the main value or line stands apart from the rest of the display.

Mechanism: Emphasizing one value, line, or insight directs attention to what matters most, instead of forcing viewers to treat all marks as equally important.

Evidence: Practitioners reported using visual highlighting in static visualizations to direct attention. They emphasized specific values or lines rather than showing all data equally because it improved readability and engagement, and they used storytelling to help highlight what was important (Schuster et al., 2023).

context

Use when the chart has a main takeaway

  • User Goal: Direct attention to the main takeaway.
  • Task: Help viewers read what matters most in the display.
  • Data: Multiple values or lines appear together and could otherwise look equally weighted.
  • Chart Setting: A static visualization without relying on animation or interaction.
  • Audience: Readers who benefit from clearer visual guidance.
  • Success Criterion: The important value, line, or insight is easy to notice first.

exceptions

Do not use when nothing should be singled out

Break it when: The chart has no specific value, line, or insight that needs to be foregrounded. Why: This move depends on making something important stand out.

costs

What emphasis costs

Sacrifice: The chart no longer gives every element equal visual weight.
Risk: De-emphasized data may receive less attention.
Mitigation: Keep the background data visible while clearly foregrounding the key value or line.

mistakes

Common emphasis mistake

Mistake: Giving every value or line the same visual weight. Why it fails: Key insights can get lost, and the chart becomes harder to read and less engaging.

check

Check whether the focus is obvious

Failure Sign: No value, line, or insight stands out from the rest of the chart.
Quick Check: Look at the static chart and identify the intended key value or line; if it is not immediately more noticeable than the surrounding data, the emphasis is too weak.

fix

How to strengthen focus

  • Highlight the specific value or line that carries the main point.
  • Dim less important background data so the highlighted element stands out.
  • Restructure the layout so the important element is easier to find in the static view.

References

Schuster, R., Koesten, L., Möller, T., & Gregory, K. (2023). Who is the Audience? Designing Casual Data Visualizations for the “General Public.” arXiv. https://doi.org/10.48550/arXiv.2310.01935