VISUAL COMMUNICATION:
We experience the world predominantly through our eyes. Recognition of vision's unique power has led to the development of many new forms of visual communication. Our eyes are now seen as valuable targets for visual content-messages written in light that reach out to tickle our retinas and thus our minds-hoping to make an impression. Visual communication comes in many forms, many of which are designed to entertain us through moving images, such as film, television, and video games. Visual technologies such as these have become quite sophisticated, but some forms of visual communication remain primitive by comparison, crudely attempting to deliver information that is far too important to be displayed so poorly. Graphs-the visual representation of quantitative information-are often sad examples of a crude visual medium. This is particularly sad, because the skills and technology needed to effectively present quantitative information in graphs are not complicated, but they remain rare nonetheless.
Graphs were invented to bring meanings in quantitative data to light, which could not be discerned from a table of numbers. Whether you display data in a table or a graph should not be an arbitrary decision. They serve very different purposes. Tables work marvelously when you wish to look up particular values or you need precise values. Graphs, however, make meaningful relationships between values visible by giving them size, shape, and color. There is no substitute for a well-designed graph when you wish to see or communicate meaningful trends, patterns, and exceptions in quantitative data.
Take a moment to study the table in Figure 1. If you want to know the amount of domestic sales for the month of July, it's extremely easy to find. If you want to make a simple comparison of two values, such as domestic and international sales in April, the table supports this operation as well. If you wish to discern trends or patterns of any sort, however, tables aren't very helpful.
Take the same set of values and display them in a graph, however, and trends, patterns, and exceptions become immediately recognizable. Look at Figure 2 and see for yourself. What are some of the stories this set of data reveals that were not obvious when you examined the table?
Here are some of the stories that you probably found quite easily while examining this graph:
- Domestic sales are trending upwards across the year as a whole.
- International sales are relatively flat across the year as a whole.
- An exception to the norm of international sales occurred in the month of August, when they took a dive.
- There is a cyclical pattern in domestic sales; one that repeats itself every quarter. Sales are lowest during the first month, they grow during the second month, and they reach their quarterly peak during the last month, then they go down again in the first month of the next quarter.
These characteristics are obvious in the graph because they are expressed in a medium that is particularly good at revealing such characteristics. Graphs are the only means of communication that reveals relationships between values in this clear and direct manner. They do so by taking advantage of visual perception-our most powerful sense.
PREREQUISITES TO EFFECTIVE VISUAL COMMUNICATION
As with all forms of communication, the first step is to determine what you want to say. To communicate your message effectively, you must know what your message is. I suspect that most people who create graphs don't take the time to think about what they want to say before producing them. If you examine a graph and its message is not clear, there's a good chance that the person who created it didn't have a particular message in mind.
Once you know what you want to say, effective visual communication is achieved by displaying information in a way that enables people to clearly see an accurate representation of your message and understand what they see. To do this, you must understand a few things about how people see (visual perception) and how people think (cognition). You must present your message in a way that takes advantage of the strengths of visual perception while avoiding its weaknesses, and in a way that matches the human thought process, augmenting it when necessary to work around limitations.
