Dot strip plots are a space-efficient way of visualising the distribution of values across multiple categories where each dot will typically represent a single data point. When formatted correctly, these charts can be really effective at comparing multiple groups, identifying outliers for datasets of all shapes and sizes.
Let me show you how to make one in Tableau Desktop!
For this example, we will be using data about London’s Poverty and Inequality profile from Makeover Monday 2024 Week 38 (try the challenge out yourself!).
The Dot Strip Plot
Drag your dimensions (in this case, Category and Sub-Category) onto Rows. Drag your measure onto Columns.
As we want each dot to represent a single borough (to understand the distribution of each dimension throughout London boroughs), drag Borough onto the Detail marks card. Change the Marks dropdown to Circle.
We basically have the dot strip plot already but to make it more useful, let’s do a bit of formatting!
Formatting Tips
Jitter:
- Use RANDOM() to offset the marks to reduce overplotting and showcase individual points more clearly by spreading out the data. Ensure that this is created in the Rows (or Columns if your measure is set to Rows).
Reference Lines:
- Add a reference line to help users better understand the context of the chart. Given the current dataset, a line indicating the regional benchmark of each dimension along with the upper and lower thresholds would be particularly useful for comparisons across areas.
Colour:
- Decrease the opacity to make it more obvious when marks are overlapping (and therefore, where most of the data lies). You can also add a border to the marks to further highlight this.
- Use conditional formatting in the form of a calculated field to change the colour of the dots depending on where they lie on the chart. In this example, I compared the measure value to the regional benchmark (which can be selected by the user) to emphasise whether or not they were above and below the benchmark. I also did something similar with the background of the chart by filling above/below the benchmark lines.
Here is my final dashboard with the dot strip plot for Makeover Monday 2024 Week 38 that makes use of all these tips and tricks.
You can find it published on Tableau Public here!