Bars, Pies, Doughnuts & Tables – Visualization of Proportions

Visualization of proportions is one of the most common visualization types encountered in the media. Stacked bar charts, doughnut and pie charts – the most common visualizations of proportions – have all keen advocates and critics, and there are conflicting results about their performance. This study presents an experiment with a basic but ecologically valid task to evaluate the performance of these techniques. The result shows that the stacked bar chart is superior to doughnut and pie charts in task performance. However, 75% of the participants regarded pie charts as the most pleasing or second-pleasing to use, and almost half of the participants (44%) perceived the pie or doughnut chart to be the fastest visualization to understand. Only six participants recognized the bar chart as the fastest technique, and half of them still preferred the pie chart over them. This subjective preference at the expense of performance may explain why pie charts are so widely used in spite of being criticized.