Some more JunkChart

Martin Theus posts here an example of poor charting or “junk charts”. I’ve had the opportunity to work with many organizations as a management consultant, and it’s sad to report that is more the norm than the exception to see charts like that one in the workplace.

Feeding my bad habit of thinking anytime anytime I see a chart how would I restate it to make it cleaner, here is how I would do it. On top, the original chart, below a proposed improvement.

The key questions, whenever one draws a chart, are “Who is my audience?” and “What is the message I want to communicate to them?”. For such chart, I would imagine the audience are the users of a software system for which we are reporting the different sources of errors”, and the underlying message, most likely, is what are the most relevant sources, so we can fix them.

In the original chart, transparency, 3D and color are used, but they are not adding any new information. The pieces of the pie do not show any meaningful order, either. The audience will have to look at the callouts to see which category corresponds to which piece of the pie, and their work is going to be harder by having to follow the callout lines that in some cases converge.

What makes the second chart better?

• The improved chart uses sorting as a way to help the audience. The largest sources of errors appear first.
• Once the data is sorted, it uses the Pareto principle to focus on the main sources of errors, removing from the audience’s eyes a lot of unnecessary detail. Today’s interactive media allows to drill-down into details with a click. Printed presentations can always have backup charts. Simple is beautiful. The Pareto principle is one of those “business commonsense” things that almost everyone has heard about, to the point is almost a cliche, yet people fail to appreciate how powerful it is.
• The use of color is non-gratuitous. Color is very powerful. Most people can differentiate between colors without effort. But they can also get quickly overwhelmed if many colors are used in a chart. Think twice before adding a new color to your chart. Is it communicating something?
  The improved chart has some visual effects, like drop shadows and some color gradient, to make it more appealing. However they don’t work against how easily the message will be understood by the audience, they don’t leave out people with difficulties to tell colors apart, and they will not break when you make a black and white printout of the chart.