How can you choose a chart type that is accessible to all users?

1 Know your audience

Before you create a chart, you need to know who will see it, how they will access it, and what they need to understand from it. Different audiences may have different levels of data literacy, visual acuity, color perception, and cognitive abilities. They may also use different devices, browsers, or screen readers to view your chart. You should design your chart with these factors in mind, and test it with a representative sample of your audience, if possible.

2 Choose the right chart type

The chart type you choose should match the purpose, message, and data of your visualization. For example, if you want to show a trend over time, a line chart may be more suitable than a pie chart. If you want to compare proportions, a bar chart may be more effective than a scatter plot. If you want to show relationships, a correlation matrix may be more informative than a stacked area chart. You should also avoid using too many chart types in one dashboard, as this may confuse or overwhelm your audience.

3 Use colors and labels wisely

Colors and labels can enhance or hinder the accessibility of your chart. You should use colors that are contrasted, consistent, and meaningful. For example, you can use a color-blind friendly palette, use the same color for the same category across charts, and use colors that reflect the values or emotions of your data. You should also use labels that are clear, concise, and descriptive. For example, you can use axis titles, legends, captions, and annotations to explain your chart, and avoid using jargon, abbreviations, or ambiguous terms.

4 Add alternative text and captions

Alternative text and captions are essential for making your chart accessible to users who cannot see it or have difficulty seeing it. Alternative text is a brief description of your chart that is read by screen readers or displayed when the image fails to load. Captions are longer explanations of your chart that are displayed below or beside it. You should write alternative text and captions that summarize the main point, message, or insight of your chart, and include the chart title, type, data source, and any relevant details.

5 Test and improve your chart

The final step to choosing a chart type that is accessible to all users is to test and improve it. You should check your chart for errors, clarity, and readability. You can use tools such as WebAIM's Color Contrast Checker, Google's Data Studio Accessibility Scanner, or Microsoft's Accessibility Checker to evaluate your chart's accessibility. You can also ask for feedback from your audience or colleagues, and make adjustments based on their suggestions.

By following these tips, you can choose a chart type that is accessible to all users, and create data visualizations that are engaging, informative, and inclusive.