Accessibility in business graphics – color blindness
Posted: February 9th, 2010 | Comments: | No Comments »Accessibility is a topic that tends to get short shrift in business. Which is too bad. For if business information is inaccessible to those who need it (employees, partners, investors, etc.) because of process, format, or channel, it is often the business that suffers the most.
An easy way to make your information more accessible is through color choice in charts and graphs. In business, certain colors are used more frequently (and have stronger connotations) than others:
- Green typically = Increase, Growth, Positive, On Track
- Red typically = Decrease, Loss, Negative, Danger, Problems
But to someone who is “red-green” color blind, distinguishing between these colors is often impossible. And this is no small problem – it is estimated that roughly 9% of the overall population suffers from “red-green” color blindness (predominantly affecting Caucasian males).
The above illustration is a part of the Ishihara color test. For most people, the number “74″ is visible in the circle. However, for those afflicted with visual impairments for color, they may only see the number “21″ or no number whatsoever.
So what? Let’s see how this applies to business information.
In the “stair step” chart above (from Occidental Petroleum’s Q4 2009 earnings presentation), Occidental uses green to show the magnitude of positive factors impacting earnings growth and red to show negative factors.
However, for some people afflicted with red-green color blindness, the positive and negative factors look relatively the same. And since the label on the negative factor (sales price) is shown as an absolute number (not reflecting its negative value), the viewer may be confused as to the meaning of the chart.
In some business communication, the meaning is less obvious. The positive or negative direction of for a number, for example, may simply be highlighted by the use of green or red in font color. To someone who is “green-red” color blind, the meaning connoted by the choice of color would be entirely missed.
As graphics become more and more important in communicating business information (often without accompanying textual explanation – e.g. dashboards, business intelligence software), it is essential that business information is conveyed optimally through “accessible” color choice.
