Charting Tips: Bar Charts & Column Charts

So I want to try out a little post series that covers good chart drawing practices when visualizing data.

For this first post, I will look at Bar Charts and Column Charts. These charts use either horizontal (Bar Charts) or vertical bars (Column Chart) to show discrete, numerical comparisons across categorical data. One axis of the chart shows the specific categories being compared and the other axis represents a discrete value scale.

Always start at a zero baseline. Truncation can exaggerate the differences between bars.

Don’t draw the bars too narrow as this focuses attention on the negative space more

Labelling can problematic with vertical bars when there are a large number of bars. Therefore, it’s better to a (horizontal) bar chart

Don’t use radically different styles between the bars

Do not use 3D Bar Charts as they are hard to read and compare values on.

Keep the ordering of categories logical (for example alphabetically or by magnitude)