Simplification is a matter of removing design elements from a visualization that do not contribute knowledge or insight. Unnecessary design elements could include borders, heavy grid lines, shadows, extraneous colors, gradients, textures, or other decorative elements. These are also referred to as “chartjunk” by Edward Tufte in his book The Visual Display of Quantitative Information.
The result of simplification is that it reduces the number of visual elements on a page competing for attention. This reduces cognitive load and can help draw the reader’s attention to the most important findings. Combining simplification with emphasis is a powerful way to increase the force and focus of one’s message.