Bar charts enable us to compare numerical values like integers and percentages. They use the length of each bar to represent the value of each variable. For example, bar charts show variations in categories or subcategories scaling width or height across simple, spaced bars, or rectangles.
Bar charts can represent quantitative measures vertically, on the y-axis, or horizontally, on the x-axis. The style depends on the data and on the questions the visualization addresses.
A good bar chart will follow these rules:
- The base starts at zero
- The axes are labeled clearly
- Colors are consistent and defined
- The bar chart does not display too many bars
When creating a bar chart, do not:
- Make each bar a different width
- Cram too many bars into subcategories
- Leave the axes unlabeled