The main purpose of a chart is to help people understand and compare. Our charts should be:
- Useful. To help people understand a chart, we pair data with interpretation.
- Trustworthy. Include clear copy, including accurate labels, units, and timeframe.
- Based on behavioral science. Use charts to nudge people to change their behavior.
Creating a chart
Get your story straight, then choose the right format.
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Articulate the concept
Before you start making a chart, figure out what you want to communicate. The same data can have different interpretations, so it’s up to you to decide what story to tell.
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Choose the right format
Keep in mind that not every piece of data needs to be displayed in a chart—often, a simple table or other visual comparison will do.
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Add insight or interpretation
Call out an interesting aspect of the data in a short sentence like so: Heating accounts for 36% of your energy use.
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Double-check the details
Include in all chart types:
- Heading (descriptive, use sentence case)
- Labels
- Units of measurement
- Reference to time
- Insight or interpretation
Depending on the content, charts can also have:
- Key
- Caption
- Tooltips
- Related body copy
What type of chart to use
| Bar and column chart | Line chart and area chart | Pie chart | |
|---|---|---|---|
| Best for… | Comparing using same characteristic Discrete amounts | Trends Changes over time Continuous series | Part-to-whole relationship Total/100% |
| Emphasis on… | Relative size of bars | Relationship between points Peaks and valleys | Relative size of slices |
| Pros | Easy to compare | Shows lots of data at once Visual interest Color | Visual interest Color |
| Cons | Can be hard to compare slices |
