Effective Visual Communication

Claus O. Wilke

2025-03-27

How did I get here?

Three key principles of effective visual communication

  1. Tell a story
  2. Prepare figures that make a point
  3. Make your figures accessible

1. Tell a story

What is a story?

A story is a collection of observations, facts, or events presented in a specific order such that they create an emotional reaction.

Every story needs an arc

Opening

Challenge

Action

Resolution

Every story needs an arc

Opening

Challenge

Action

Resolution

Challenge and resolution are
the two most important parts

Mapping my story onto this format

Opening: We need to make many data visualizations in my lab

Challenge: I end up telling my students the same things over and over

Action: I go and write a book about data visualization

Resolution: The book is written. But now I teach the material, so I still keep saying the same things over and over

Other story structures

Action

Background

Development

Climax

Ending

(Better for action movies
than for scientific reports)

Mapping my story onto this format

Action: In May 2017, I embark on a major project: Write a book on data visualization

Background: I do this because we need to make many data visualizations in my lab, and I end up telling my students the same things over and over

Development: Writing the book takes me almost two years; along the way, I add many features to ggplot2 and become a member of the ggplot2 team

Climax: The book is released in April 2019

Ending: Now I’m a dataviz teacher

Other story structures

Lead

Development

(Commonly used in newspaper articles)

Mapping my story onto this format

Lead: Because I see the need for more education in data visualization, I have written an entire book about the topic

Development: I had previously written an R package to improve figure design, but it wasn’t sufficient: Good judgement cannot be automated

So I wrote a book; the book is entirely about concepts, not about coding, and it is meant as a resource for anybody doing data visualizations, regardless of their preferred visualization software

2. Prepare figures that make a point

Don’t overload your figures with irrelevant detail

 

Focus on the specific message you want to convey

 

American and Delta have the shortest delays

Make your figures memorable

Make your figures memorable

How to use figures to tell a story

  • Every figure needs a clear purpose within the story arc
  • A complete arc will usually require at least two figures

Example: Preprints in biology

 

Opening

Example: Preprints in biology

 

What happened in 2014 to curtail the growth?

Challenge

Example: Preprints in biology

 

bioRxiv opened in 2014

Resolution

3. Make your figures accessible

These design elements all affect accessibility

  • Font/symbol size
  • Font choice
  • Color choice
  • Contrast

These design elements all affect accessibility

  • Font/symbol size
  • Font choice
  • Color choice
  • Contrast

Don’t use tiny fonts!

Both text and symbols are way too small

Don’t use tiny fonts!

Text and symbols are reasonable but could be bigger

Don’t use tiny fonts!

Symbols too small compared to text

Don’t use tiny fonts!

Make fonts bigger than you feel comfortable

Don’t use tiny fonts!




Make fonts bigger than you feel comfortable

Rule of thumb:
Keep ratio of largest and smallest font size < 2

Be aware of color-vision deficiency

5%–8% of men are color blind!

Red-green color-vision deficiency is the most common

Be aware of color-vision deficiency

5%–8% of men are color blind!

Blue-yellow color-vision deficiency is rarer but does occur; it is more common in older people

Be aware of color-vision deficiency

Choose colors that can be distinguished with CVD

Consider using the Okabe-Ito scale

Name Hex code    R, G, B (0-255)
orange #E69F00 230, 159, 0
sky blue #56B4E9 86, 180, 233
bluish green #009E73 0, 158, 115
yellow #F0E442 240, 228, 66
blue #0072B2 0, 114, 178
vermilion #D55E00 213, 94, 0
reddish purple #CC79A7 204, 121, 167
black #000000 0, 0, 0

CVD is worse for thin lines and tiny dots

Color encoding alone is not always sufficient

Iris virginica and Iris versicolor are difficult to tell apart

Rearranging colors and using different shapes helps

Orange provides much better contrast next to green

When in doubt, run CVD simulations

Original

When in doubt, run CVD simulations

Original

Pay attention to legend order

 

Legend order does not match visual order of the lines

Pay attention to legend order

 

Legend order does match visual order of the lines

Even better: Don’t use a legend at all

 

This technique is called “direct labeling”

Additional materials, examples with R code

https://wilkelab.org/SDS366

Further reading

Acknowledgements/Disclaimer

  • Claus Wilke is the Jane and Roland Blumberg Centennial Professorship in Molecular Evolution at The University of Texas at Austin

  • Claus Wilke has not received any specific funding for the work presented here

  • Claus Wilke receives royalties from the sales of his book Fundamentals of Data Visualization