What are dot plots in data visualization?

Dot plots

Dot plots, as the name suggests, use dots to represent the position of value on the axis.

Dot-Plot-Example
An example of a Dot Plot

When to use dot plots?

Comparisons: We are best able to make comparisons via the position of objects on a scale. This makes dot plots very effective for comparisons.

Cleaner charts: Dot plots make the chart area less cluttered. They have a high data-ink ratio.

Non-zero baseline: Dot plots are judged by position along the horizontal axis. Length is not an issue with dot plots. So dot plots do not need a zero baseline.

Let’s see 2 examples to understand this better.

Using dot plots – Examples

To replace bar charts: Dot plots can be used in place of bar charts. They are especially useful when the values being compared are similar. It is also a good idea to replace your bar charts with dot plots if you want to give some variety to your presentations.

Bar_Chart_Similar_Values
A bar chart with similar values

In this bar chart, look how close the values are. You can instead use a dot plot.

Dot_Plot_Similar_Values
A dot plot with similar values

Dot plots are not as dense as a bar chart, so they easy on the eyes too.

To replace clustered or grouped bar charts: Dot plots can also replace clustered or grouped bar charts. I think this works especially well when comparing before and after changes or changes over 2 time periods.

In this example below, we are comparing the percentage of social logins for 2 time periods.

Clustered_Bar_Comparison
A clustered or grouped bar chart

With a clustered bar chart, it is easy to see values for say Google, but it takes a bit of effort to compare the values for all the social networks. This gets worse as the number of categories increase.

Dot_Plots_Comparison
A dot plot with ranges

Dot plots make this comparison easier. It is easy to see how the social networks rank for the percent of logins. It is also clear who saw an increase, who saw a decrease and by how much. The type of dot plot in this example is called a range plot.

Here is another example of using a dot plot: DESI Index Makeover Chart

Have you used dot plots in your presentations? Try using them in place of bar chart or clustered bar charts and let me know how it works in the comments below.

1 Comment

  1. Pingback: Makeover Monday: Which states produce the most wind energy?

Leave a Reply

You have to agree to the comment policy.

This site uses Akismet to reduce spam. Learn how your comment data is processed.