A Butterfly Chart (also called a Tornado chart) is used to compare two sets of data that have similar metrics. In this chart two bar charts are displayed side by side to analyse the difference between two data series and the data categories are listed vertically instead of the standard horizontal presentation.
It is called as butterfly since there is a gap in the centre which denotes the categories and the bars on either side resemble the wings of a butterfly.
As the bars on either side vary in length due to data values of the corresponding data series, it is also called Tornado chart.
The main use of the butterfly chart is comparison of two data sets sharing the same parameters.
- Population Chart ( males vs females)
- Survey Results (Yes vs No)
- Product Sales ( Location A vs Location B)
- Department Headcount ( Joinee vs Resignee)
In our example we are using the Butterfly Chart to denote the joiners / resignees across department.