Bubble
A bubble chart uses bubble to represent values for three different variables. The position of each bubble on the horizontal and vertical axis indicates values for an individual data point. The size of the bubble indicate the third value. Bubble charts are used to compare and show the relationships between categorised circles or to analyse for patterns/correlations.
Introduction
Bubble chart are used for:
Show relationship
Distribution
Recommandations for a perfect Bubble chart:
Prioritize your variables.
Try different combination : indeed the relationship between the variable A and B is much more obvious than the relationship with the variable C.
Show a legend for bubble size.
Usage
When to use
If you want to compare independent values. If you want to show distribution or relation.
When to avoid
If you have a small dataset
Anatomy
A bubble chart (aka bubble plot) is an extension of the scatter plot used to look at relationships between three numeric variables. The objective is to link 3 indicators to illustrate correlations. Perfect for comparing complex sets, indeed the bubbles will allow you to visualize information simply and quickly, which will reduce your readers' thinking time
A bubble chart is always represented with :
Dual axis prefered centered like on the example below.
Include a legend on your chart including a bubble reference size for visual reference.
Make sure that the bubbles’ areas correspond with the third variable’s values
If a variable takes negative values, you might have filled circles indicate positive values and unfilled circles indicate negative values
