A grouped bar or column chart (also known as clustered or multi-series chart) is handy for comparing multiple sets of data items in the same categorical group. In short, it is a way to make more complex comparisons by adding more information with the support of multiple columns or bars.
As in the standard bar chart, rectangles are compared by length. In this specific case, instead, bars are grouped by a second categorical variable; thus, the grouped bar chart will compare bars of the same color belonging to the various categories plotted on the x-axis.
When to use a grouped bar chart
As mentioned before, a grouped bar chart is excellent for comparisons across multiple categories of data. It’s advantageous to visualize how the second category variable evolves within each level of the first or observe how the first category variable changes across the second level.
Among the pros of the grouped chart, the facility makes direct comparisons of vast data series per category and the possibility to visualize changes over time.
Moreover, we can’t mention some of the cons: the more significant the categories, the more challenging the chart will be to interpret. Not by chance, the advice is to limit the categories or series, so the audience will be more comfortable at focusing on the key takeaways.
Bars or columns chart?
The choice between the grouped vertical column chart or the grouped horizontal bar chart depends on the categories’ quantities and the length of the labels.
A grouped horizontal bar chart allows the host of many categories or series to improve the readability. To not forget, the horizontal bar chart is more comfortable to read for western cultures.
How to create a grouped chart on BStreams
- Add a new project
- Drag the grouped bar or column and drop it on the canvas
- Select the sample dataset
- Choose two dimensions and one metric
- Click apply to show the result
Example of a grouped column chart
For the following example concerning the Top 10 Richest Men in the World – Comparison by Year, we have chosen a grouped column chart, as we would like to analyze the yearly revenue of men present in the list.
We selected Name as a first-level dimension and Year as a second-level dimension, while Net Revenue billion USD as a metric.
The first dimension goes to the x-axis while the second one goes to the legend. Expand the Legend section and toggle on it to easily understand which color is associated with a specific year.
As you can see from the image above, not all names are visible because BStreams is wise enough to prevent the labels from overlapping each other. But the chart loses some of its readability.
In this case, probably grouped bar chart would be the best option:
This doesn’t mean choosing a horizontal view is alway the best choice, but there are some cases, like this one, when it is likely advisable.
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