Article 07 · UX Principles
Use the Chart the Eye Can Read
A practical UX principle for clearer data visualization.
Core principle
Match visual encoding to the comparison the user needs to make.
When values are nearly equal, a pie chart asks the eye to compare angles — one of the least precise visual judgments.
Visualization is an interface
A chart is not decoration. It is an interaction between information and human perception. The format should help the user answer a question quickly and accurately.
Length is easier than angle
When categories have similar values — such as 33%, 34%, and 33% — pie slices are difficult to compare. Bars aligned to a common baseline make subtle differences visible because the eye is better at comparing length than angle or area.
Begin with the decision
Before selecting a chart, ask what the user needs to determine: compare categories, understand a trend, locate an outlier, see distribution, or examine a relationship. The chart type should follow the task.
Reduce decoding work
Direct labels are often easier than legends. Meaningful ordering is easier than arbitrary ordering. Clear units, baselines, and annotations prevent the user from translating the visual in their head.
Show what requires attention
Enterprise dashboards frequently display everything because the data exists. Better visualization prioritizes the exception, change, risk, or next decision. The goal is not to expose data — it is to make data usable.
Do not visualize the data you have. Visualize the decision the user needs to make.
Design takeaways
- Use aligned bars for close comparisons.
- Choose charts based on the user's question.
- Label information directly whenever practical.
- Prioritize change, risk, and action over data volume.
Categories: UX Principles · Design Leadership · Human-Centered Design