Data Ink Ratio

Imagine this. You are in a meeting and someone is presenting a chart to the group. You look at the chart and try to grasp the information. But there are several elements on the chart distracting you to consume the information right away. You ask yourself, are all the elements on this chart necessary? Can some elements be removed without taking away the core information from this chart? Is there any guideline or principle that can be applied to make this chart more consumable?  

Well you are in luck. There is a principle created just to achieve this and it's called Data Ink Ratio.

It was introduced by Edward Tufte who is considered one of the major figures in the field of data visualization.

Tufte argues that a chart should only contain those elements which if removed, the chart will lose it's core information.

Data Ink Ratio can be calculated as:-

Let look at an example.

Below is a chart with low data ink ratio. When you carefully examine the chart, you can find some elements which can be removed without loosing information on the chart.

 And below is high data ink ratio version of the same chart.

Notice following changes:-

• Grid lines are removed.
• Numbers are formatted to appropriate unit.
• "Category" and "Sales" header are removed as title provide same information.

And there you have it. A nice clean looking chart. By following this simple concept you can create less distracting and more consumable charts.