What is a Bubble Chart & Why Do You Need One in Marketing?

Bubble charts are used for a variety of reasons and across a wide range of different industries. But what is a bubble chart and why is it necessary to use them in the world of marketing? We’ll be discussing that in this article, along with some tips for creating your own, if you haven’t made one before.

What is a bubble chart?

A bubble chart, also known as a bubble plot, builds on the traditional scatter graph. Typically, bubble charts are used to look at the relationships and trends between three numeric values, but some bubble charts can contain more or less numeric values. Much like a scatter graph, each point on the chart will represent a single data point. 

A bubble chart still consists of an X and a Y axis, with each point on the bubble chart being indicated by a vertical position, a horizontal position and, lastly, the dot (or bubble) size. The larger the bubble, the higher the value. The value of each bubble and its size should be indicated in something called a ‘legend’, or a ‘key’, as it’s more commonly known.

When would you use a bubble chart?

A bubble chart acts much like a scatter graph, only the points are larger or smaller depending on the value, resembling something of a bubble. A bubble chart is used when you want to show relationships between numeric variables and, therefore, depict results in a clear, easy-to-understand way. 

Bubble charts are used in a number of industries and for a variety of reasons, including in marketing when looking at user behaviour and user experiences. Bubble charts can be useful in marketing when looking at certain trends, the results from which can be used to devise excellent marketing strategies and content creation.

How do you interpret a bubble chart?

First of all, make sure you’re looking for relationships between the X and Y variables. There will either be a positive linear trend, a negative linear trend or no relationship or trend at all. This all depends on the direction the bubbles are going. If the bubbles go from the bottom left corner, in a line, up to the top right corner, then this is a positive linear result. 

If, however, the bubbles go from the bottom right hand corner of the chart and go, in a line, up to the top left hand corner, this depicts a negative linear result. If the bubbles are all over the place, then there’s no real trend to be seen. This is, essentially, all you need to know when it comes to interpreting a bubble chart. 

Like with other graphs, you’ll need to look at the values and labels on the X and Y axis as well as the legend or the key. The size of the bubble will depend on its value. The small it is, the lesser the value, the larger it is, the higher the value. This makes bubble charts extremely easy to use and valuable to many people, including those in the marketing industry.

Marketers will need to know a wide range of things, from user heat maps and analytics to blog post views and popular keywords and phrases, a bubble map is a quick and easy way of displaying all the information you need to know to optimise content for target audiences. If you’ve never used one before, there are some tips below for creating the perfect one.

8 tips for creating a bubble chart

If you’ve never made a bubble chart before, for any reason, then we’ve provided some tips below to ensure you’re producing a bubble chart that’s high-quality, easy to read and depicts all of the relevant information needed to extract valuable data.

1. Make sure it’s labelled

Like with any graph or chart, you need to make sure that the X-axis and Y-axis are clearly labelled. It’s also imperative that the value of the bubbles, or circles, are also depicted to mitigate confusion before someone has even begun looking at the information the chart holds.

2. Don’t stray too far from circle shapes

It can be tempting to use other shapes besides circles, but the very nature of a bubble chart means that you can’t deviate from the circular form, even if they’re similar to circle shapes. Try to avoid even using oval shapes as it can lead to inaccuracies and cause confusion. 

3. Be cautious of changing the diameter of the bubble to avoid confusion

You need to stick to relativity. For example, the largest circle on the graph should depict the greatest value. Unless two values are the same, try not to use the same diameter for each bubble and do not make bubbles of a lesser value bigger than a circle of a higher value. By changing the diameter of the circle too much, you could either skew the values or turn the circles into other shapes.

4. Scale the bubble by value

As already touched upon, don’t make the circles too big or small, depending on the values you have. Take a look over the numbers you have and plot the largest and smallest circles first. Either that, or you can do some trial runs first using a separate piece of paper and then plot the different sized circles on the graph once you have finished.

5. Limit the number of points you plot

When it comes to a bubble graph and the number of points you have, it’s important to make sure that you aren’t squeezing too many bubbles into the chart, as it could become confusing to read and interpret. When it comes to a bubble chart, the less data points you have the better as too many could cause the chart to blur into one.

6. Ensure the map has a legend or a key

When it comes to a legend or a key on any chart, including bubble charts, there are some things you’ll need to include to make interpretation in the future far easier and more straightforward. Some of those things are as follows:

• Something to help viewers compare and understand bubble sizes and values
• Something to identify colours and bubbles that represent different values

7. Be sure to show the trends

A bubble chart has a sole purpose of displaying trends, with the third variable making a clear point, in the form of, you guessed it, bubbles. If, however, the bubbles size doesn’t look to make much of a difference, then perhaps you’re using the wrong type of chart – look to bar graphs or line charts instead to make things easier.

8. Don’t leave out negative values

Where a graph is really only used to try and display positive values and trends, it’s important that you’re transparent when it comes to the results you find and that includes plotting the negative values as well, but only if it truly adds to the value of the plot itself.

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