One of the key goals in creating effective charts is to reduce cognitive load, in other words, to minimize the amount of mental effort required for someone to understand the message. Every extra element on a chart competes for attention, and small distractions can add up quickly.
A common culprit I’ve noticed is the overuse of decimal values. For most purposes, they don’t add meaningful precision but do add visual clutter. For example, showing 42.137% instead of 42% forces the viewer to process extra digits that don’t contribute to the story. Unless decimal values are truly necessary for accuracy or context, they should be removed to keep the visualization clean and easy to interpret.
Simplifying numbers not only makes charts more visually appealing but also ensures that the audience can focus on the insight rather than the formatting.
What other techniques have you used to reduce cognitive load in your visualizations?