Excel has some powerful charting tools that are easy to use - so easy that you'll be tempted to experiment. That's good, but be careful. If you don't know what you're doing, you could generate some pretty bad charts. At the very least, they'll be ineffective. Even worse, you'll use a specialized type that simply doesn't represent your data, and you'll look inept.
Remember, the purpose of any chart is to make a point or help the reader draw a conclusion. Your data simply won't work with every graph type. When in doubt, here are five chart types to avoid.
Pie charts present a bunch of proportional pieces and it's usually impossible to glean any worthwhile information from the results. In the following pie chart, can you quickly discern which month rates lowest? You could add data points, but the overall chart is still ineffective - what point does it make? None really.
While we're on the subject, if one pie chart is bad, two pie charts - as in pie of pie and bar of bar - are worse. Only the geekiest among us will have a clue what they're looking at. Just don't do it unless you're required by law or something.
Most of us will never need a radar chart, nor would we know how to create a good one, if we did. To most of us, it's just a big mess. You can't make any kind of conclusion about your data. They're confusing and they make me dizzy. Excuse me while I go find a peppermint…
In defense of radars, there will be folks who assert that used correctly they're effective. Let me repeat myself, use them if:
- you know what you're doing and
- your data truly requires a radar chart
Otherwise, stay away from them.
A donut chart is just a pie chart with a hole in the middle. For most of us, they provide no charting value. It's difficult to compare values and the more values you have, the more difficult that comparison becomes.
Adding a third dimension to a chart just adds the potential for confusion. They look kind of cool, sometimes, but I can't look at most of them without crossing my eyes. Excuse me while I go find an aspirin…
I don't recommend surface charts for the same reason I don't like three-dimensional charts. They look cool, but you lose part of the story - it's difficult to see patterns. Information is just lost.
Those of you who create charts regularly and who do so with great skill might want to argue with me. First, you'll claim that the right chart for the right task is always useful. Second, you'll draw attention to the fact that the example data just don't fit these chart types. You are right in both assertions, but that's my point too - unless you know what you're doing, don't use these charts!
I have a challenge for those of you who skillfully use these chart types. Share a successful example with us so we can all learn from your experience.
Susan Sales Harkins is an IT consultant, specializing in desktop solutions. Previously, she was editor in chief for The Cobb Group, the world's largest publisher of technical journals.