Pie charts should be banned. That’s the view of many people who groan when they see colourful but confusing pie charts.

Pie charts are only useful when you want to compare proportions or percentages. If you want to compare values, use a bar chart. See the pie chart and bar chart example below. Which one is clearer?

Death by pie charts is like death by PowerPoint – too much information kills. If you have more than four or five values, a pie chart becomes too complicated and defeats the object of a graph. One way around this is to use the pie-of-pie option to split out the long tail of small values into a separate pie, leaving your main pie chart with fewer segments and giving greater clarity to your reader. Take a look at the example below.

Instructions about creating an Excel pie-of-pie chart will follow in the next few days.

“Chart junk” is another insult thrown at creators of Excel graphs. Anything 3D can usually be put in this category. The golden rule is “keep it simple”. Anything that makes a graph more complicated is likely to make it harder to understand, so it will transmit less information to the viewer. Keep it simple, keep it 2D.

If you still think that 3D means “more interesting”, ask yourself why you need it. If the information transmitted by the graph isn’t interesting in 2D maybe you should question the value of the information…