Criteria for Success
- Your figure leaves the audience with a clear, one-sentence main message
- You provide evidence that directly supports the main message
- Any content not related to your main message is removed from the figure
Identify Your Purpose
Figures are any visual presentations of results and come in a variety of forms. Graphs, diagrams, photos, drawings, schematics, and maps are all types of figures. Despite this variety, the purpose of all figures is to communicate two things:
- A take-away message
- Evidence showing your message is true
Your message is the reason you want to show people your data! The purpose of a figure is not only to show people your data: it should also communicate the message you have learned by interpreting that data.
Analyze Your Audience
An accurate analysis of your audience enables you to convincingly deliver your message. Ask yourself who will be viewing this figure and whether they are specialized in your field or a more general audience. Depending on the answer, you will want to tailor the complexity of your message and the amount of evidence you present.
For example, if your figure is for publication in a field-specific journal, your audience will likely have a great deal of background knowledge about your topic. In this case, you can deliver a very specific message (e.g., “RTK ligands attenuate kinase inhibition in oncogene-addicted cancer cell lines” cite: Wilson Nature 2012 ) and provide detailed evidence (e.g., flow cytometry data). Insufficient or excessively simplified evidence will result in skepticism about your message.
If your figure will be used in a presentation for a high school outreach program, your audience will have a very different set of background knowledge. Here, you should alter the message (e.g., “Cancer cells can exhibit resistance to therapies”) to make it more interpretable and present much less evidence (e.g., number of immune cells) . Giving a general audience too much evidence will be overwhelming; they won’t be able to distinguish the evidence that supports your main message from all the other details.
Choose figure designs that best communicate your message
Just as words may be better or worse at communicating an idea, different figure designs may be better or worse at communicating your message. In designing a successful figure, consider which media, figure types, and plot types (see below for examples of each) best highlight your message.
For complex messages, multiple panels can break down a message into clear statements. Multi-panel figures will likely employ a combination of media and plot types. Use the complementary strengths of each element to communicate your message.
Media can deliver identical messages, but do so differently.
- Text and speech tell precise statements.
- Tables list information with little context or interpretation.
- Figures illustrate conclusions with evidence and are open to interpretation.
As an example, compare the table and the graph below. While both contain the exact same data, the figure suggests an interpretation and it is easier to interpret trends in the figure.
Further compare these representations to the statement, “Gene B has the highest expression,” which presents one specific interpretation. Stating this interpretation would make it clear to your reader that maximum expression matters more here than, say, average expression.
Figure types present different forms of information.
- Photos portray the subject exactly, providing concrete evidence.
- Illustrations relax precision to draw attention to a chosen theme or element.
- Graphs display processes, quantities, or comparisons.
|This schematic relaxes precision to represent a generic cell. Here, you might want the viewer to focus on just the cell’s nucleus; representing other cell structures would distract. You might use an image like this in an overview of your system or methods.
||A more realistic photo allows you to discuss multiple structures within a specific cell.
(All rights reserved by Donna Stolz, U. Pittsburgh. Reproduced here for educational purposes only.)
Plot types emphasize different types of data.
What are you trying to show with your data: a correlation, a distribution, an event in time?
When you have a distribution on hand, using a summary of your data (i.e. mean and standard deviation) can obscure interesting information about your data. For example, the three distributions below (normal, uniform, and bimodal) have the exact same mean (5) and similar standard deviations (2). A box-and-whisker plot would have hidden these distributions.
|If you’re trying to show…||…try this presentation|
|Overall distribution of data||If possible, show the entire data set|
|Large data set||Histograms, box plots: summarize features of the distribution|
|Events in time
Evolution of a variable
Tweak your figure depending on the setting
Will you be presenting your figure in an academic paper, a poster presentation, an oral presentation…? The final format dictates how your audience will interact with the figure, and how much support or explanation you will be able to provide.
|Is the figure static or dynamic?||What information goes where?|
|Presentation slides||Dynamic: can be animated||
Maximize your signal-to-noise ratio
Treat the message you want to communicate as your “signal”. Your goal is to transmit this signal as clearly as possible to your audience. Anything that interferes with communication of your message is “noise”. We’ve discussed ways to increase your signal by optimizing figure design. Here we will talk about strategies for minimizing noise.
Noise from evidence
Don’t drown your audience in data: include only the minimum data necessary to make your point. Including evidence that doesn’t directly support your message distracts from evidence that does.
Noise from presentation
The way you present your chosen evidence can also draw attention away from your message. Using the figure below, we’ll give a few common examples of how a figure can be improved to remove noise.
- The title of the figure is changed from a description of the data to a message about the data.
- Legends are moved directly next to the data they describe, so the reader doesn’t have to look back and forth and match colors.
- Color scheme is simplified and changed to draw attention the the relevant portion of data.
- Unnecessary 3D graphics are removed.
Source: Trees, Maps, and Theorems, by Jean-Luc Doumont, page 99
Many other types of noise exist. For example, unnecessary gridlines or axis labels can clutter a figure. Ask yourself what you want your audience to take away from the figure, and how you can make it easier for them to locate and focus on the relevant information.
(The metaphor of “signal-to-noise ratio” comes from Jean-luc Doumont’s book Trees, Maps, and Theorems.)
Resources for advanced figure design
Out in the world are already many great resources for styling visual communications and data. One to definitely check out is this collection of articles by Bang Wong, Martin Krzywinski, and their colleagues. Here you’ll find detailed discussions and examples on:
- Visual design principles and their relationship with clarity
- The use of color
- Styling figure elements
- The strengths and weaknesses of specific plot types
- Visualizing multi-dimensional data
- Using figures to explore data