Tableau is the most popular interactive data visualization tool, nowadays. It provides a wide variety of charts to explore your data easily and effectively. This series of guides - Tableau Playbook - will introduce all kinds of common charts in Tableau. And this guide will focus on the Side-by-side Bar Chart.
In this guide, we will learn the side-by-side bar chart in the following steps:
We will start with an example chart, then introduce the concept and characteristics of it.
Here is a side-by-side bar chart example from Speros Misirlakis's blog.
From the above chart, we can see the measure is job numbers, the first dimension is program languages, and the second dimension is the year.
Just as the literal meaning would lead you to imagine, this chart compares the program languages for 2017 and 2018 jobs side by side. It is much more explicit than two separate bar charts. To help readers comprehend, a side-by-side bar often uses different colors to distinguish bars.
As a variation of a bar chart, a side-by-side bar chart is similar to a stacked bar chart, except it puts bars side by side instead of stacking them.
Both side-by-side bar and stacked bar charts add a second dimension based on a standard bar chart. But stacked bar charts tend to show the part-to-whole relation. By contrast, side-by-side bar charts focus on the sub-category comparison on the second dimension.
Like a bar chart, a side-by-side bar chart also supports both relative and absolute comparisons. It depends on the emphasis of your analysis.
The side-by-side bar chart has the limitation of sidebar numbers. It is difficult to read with a lot of components. Two categories of bars are the best practice. Three should be the upper bound. Four or more bars will be a mess; hard to explore any useful information.
In this guide, we continue to use the Titanic dataset. Thanks to Kaggle and encyclopedia-titanica for this dataset.
It contains 887 records of the real Titanic passengers. For more details, please refer to Kaggle.
We will analyze how Parents/Children Aboard affected the survival ratio of passengers.
We have learned about data importing and preprocessing in the bar chart guide. You can refer to it if you need to.
Let's draw a standard side-by-side bar chart, step by step:
Click on Show Me and see the request for the side-by-side bar chart.
For side-by-side bars, try "1 or more Dimensions" and "1 or more Measures". Requires at least 3 fields.
This time we don't rely on Show Me. We generate a side-by-side bar chart manually.
Generate an ordinary bar chart first:
Change it into a side-by-side bar chart: drag "Survived" into Marks - Color.
Currently, it is an absolute comparison. Since we want to focus on the survival ratio, we are going to change it into relative comparison.
In the last step, let's polish this chart:
A basic side-by-side bar chart is now completed.
With the help of a side-by-side bar chart, we can make categorical comparisons across multiple data series, clearly. Passengers with 1-3 parents or children aboard have a higher survival ratio which exceeds 50%.
That is what we have achieved so far. But there are some defects in this basic side-by-side bar chart. We will optimize it with advanced features.
From the above chart, we are unclear about whether a survival ratio is high or low, relatively. So, we intend to use the average survival ratio as a reference line:
Right-click in the blank of Data Pane -> choose Create Calculate Field...
SUM(IF[Survived]==1 THEN 1 ELSE 0 END) / SUM([Number of Records]), and name it "Total Survival Ratio".
Drag "Total Survival Ratio" into Marks - Detail, prepared for the reference line.
Switch to Analytics Pane -> drag Reference Line into Table Mode.
Edit Reference Line information in the dialog which pops up automatically:
<Field Label>: <Value>.
We can see the format functions are limited in the above dialog. So we format the reference line in Format Reference Line Pane by right-clicking and choosing Format...:
We noticed that the Survived-Yes bars are missing when parents/children aboard are 4 and 6. It is unbeneficial to the comparison. So, we are going to show the empty columns:
Create two Calculation Fields, similar to the above section:
SUM(IF [Survived] = 1 THEN [Number of Records] END) / SUM([Number of Records])
SUM(IF [Survived] = 0 THEN [Number of Records] END) / SUM([Number of Records])
Drag Measure Names into Filters. And Filter dialog will show up automatically.
Check only "Yes" an "No" in the Filter dialog.
Replace previous "Survived" and "SUM(Number of Records)" with Measure Names and Measure Values.
The last step, let's polish this chart:
It looks better now. Here is the final chart:
With the help of the reference line, we can explicitly see that Passengers with 1-3 parents or children aboard are 10 to 20 percentage points higher than the total average survival ratio of 39%.
After adding empty columns, the columns are more unified, and we may pay more attention to the empty columns.
In this guide, we have learned about a variation of a bar chart in Tableau - the side-by-side bar chart.
First, we introduced the concept and characteristics of a side-by-side bar chart. Then we learned the standard process to create a side-by-side bar. Next, we enhanced this chart with a reference line and empty columns. In the end, we talked about other variations of the bar chart.
You can download this example workbook Bar Chart and Variations from Tableau Public.
In conclusion, I have drawn a mind map to help you organize and review the knowledge in this guide.
I hope you enjoyed it. If you have any questions, you’re welcome to contact me [email protected]
If you want to dive deeper into the topic or learn more comprehensively, there are many professional Tableau Training Classes on Pluralsight, such as Tableau Desktop Playbook: Building Common Chart Types.
I made a complete list of my common Tableau charts serial guides, in case you are interested:
|Categories||Guides and Links|
|Bar Chart||Bar Chart, Stacked Bar Chart, Side-by-side Bar Chart, Histogram, Diverging Bar Chart|
|Text Table||Text Table, Highlight Table, Heat Map, Dot Plot|
|Line Chart||Line Chart, Dual Axis Line Chart, Area Chart, Sparklines, Step Lines and Jump Lines|
|Standard Chart||Pie Chart|
|Derived Chart||Funnel Chart, Waffle Chart|
|Composite Chart||Lollipop Chart, Dumbbell Chart, Pareto Chart, Donut Chart|