Mark Johnson

    No pie charts

    Sunday 2nd June, 2019 - 1 min read

    Pie charts are rarely a good visualisation. They’re fine for displaying binary data, but it becomes difficult to compare relative amounts when more than two values are displayed. Even if the pie chart is displaying binary data, I still prefer a donut chart.

    This is because we’re much better at recognising a change in height than a change in area and angles. For example, are the second and fourth slice the same, or is one bigger?

    Pie chart compared to a histogram

    A column chart makes it far easier to answer this question than a pie chart.

    Pie charts also lack room for labels which often results in a legend being used. This separates the values from the label, forcing the user to flick their eyes back and forth between the pie chart and legend to interpret the graph.

    Pie chart with legend

    The data may as well be represented in a table, that’s what the legend is doing.


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