Data Presentation Styles: Why use Graphs?

• Why do we use graphs?
  • Graphs help to make comparisons easier.
• Often designers choose a style of graph that is trendy, rather than the graph best suited to the data you’re trying to present.
• The human brain gravitates towards comparing the width or height of shapes in graphs, and its usually easy to underestimate the difference in surface area when looking at a bubble chart for instance. Bar graphs are much easier to draw comparisons from because we only have to consider the length as a variable. Consider which graph type is easiest to analyse and compare differences with.
• Using circles in graphs always leads the audience to underestimate the size difference.

• Three graph types commonly used
  • Time series chart (data over time)
  • Bar chart (one variable)
  • Scatter plot (one variable on each axis)
  • Pie chart (comparing proportions)