What are the most important design principles for bar charts?

1 Choose the right type of bar chart

There are different types of bar charts, such as horizontal, vertical, stacked, grouped, or diverging. Each one has its own advantages and disadvantages, depending on the data you are working with and the story you want to tell. For example, horizontal bar charts are good for showing long labels or ranking items, while vertical bar charts are good for showing trends or changes over time. Stacked bar charts are good for showing proportions or parts of a whole, while grouped bar charts are good for showing comparisons or contrasts between subgroups. Diverging bar charts are good for showing positive and negative values or deviations from a baseline.

3 Label your bars and axes clearly

Another key design principle for bar charts is to label your bars and axes clearly, so that your audience can understand what they are looking at and what the data means. Use descriptive and concise labels that match the data and the purpose of your visualization. Avoid using abbreviations, acronyms, or jargon that may not be familiar to your audience. Use a legible and consistent font size and style for your labels, and place them close to the bars or axes they refer to. If you have too many labels or categories, consider using a legend, a color scheme, or a filter to simplify your bar chart.

4 Use color wisely

Color is a powerful tool for enhancing your bar charts, but it can also be a source of distraction or confusion if used poorly. The main design principle for using color in bar charts is to use it sparingly and strategically, to highlight or differentiate the data you want to emphasize or communicate. Avoid using too many colors or colors that are too bright, too similar, or too contrasting. Use a color palette that is appropriate for your data and your audience, and that follows the best practices for color theory and accessibility. For example, use a sequential palette for showing ordered data, a diverging palette for showing positive and negative data, or a categorical palette for showing discrete data.

6 Provide context and insights

The final design principle for bar charts is to provide context and insights for your data, so that your audience can appreciate and understand the significance and implications of your visualization. Context and insights are any elements that help your audience to interpret and evaluate your data, such as titles, captions, annotations, references, or explanations. The main design principle for providing context and insights in bar charts is to use the principle of storytelling or narration, which means using words, images, or interactions to guide your audience through your visualization and to highlight the key points or findings. Use a catchy and informative title, a concise and relevant caption, and specific and meaningful annotations to create a compelling and informative bar chart.