A stacked bar chart in Tableau is a powerful way to display parts of a whole and compare how different categories contribute to an overall total. It’s one of the most popular chart types for visualizing data with multiple dimensions and measures.
Here’s everything you need to know:
1. What is a Stacked Bar Chart?
A stacked bar chart is a variation of a bar chart where the bars are divided into segments representing different subcategories. Each segment’s size is proportional to its contribution to the overall bar total.
- Horizontal Stacked Bar Chart: The bars extend horizontally.
- Vertical Stacked Bar Chart: The bars extend vertically (most common).
Each bar represents a total, and the segments within the bar represent the breakdown of that total across different subcategories.
2. When to Use a Stacked Bar Chart?
Stacked bar charts are perfect when you want to:
- Compare overall totals for different categories (e.g., total sales by region).
- See the contribution of different subcategories to a total (e.g., sales by product within each region).
- Understand the distribution of parts within the whole and track changes over time.
3. How to Create a Stacked Bar Chart in Tableau
Here’s a step-by-step guide to building a stacked bar chart:
- Drag a Dimension (like Region or Product Category) to the Columns shelf.
- Drag a Measure (like Sales or Profit) to the Rows shelf.
- To stack the bars, drag a second Dimension (like Product Sub-Category) to the Color Marks card. This will split each bar by the subcategories.
- Optionally, you can drag the Measure to the Label Marks card to display the numerical values inside the bars.
4. Types of Stacked Bar Charts
- Regular Stacked Bar Chart: The bars are stacked on top of one another, with each segment showing the absolute value of a subcategory.
- 100% Stacked Bar Chart: Instead of showing absolute values, each bar is scaled to 100%, and the segments show percentages. This is useful for comparing the relative contribution of subcategories.
5. Customization Options in Tableau
You can customize your stacked bar chart to make it more insightful and visually appealing:
- Color: Use distinct colors for each subcategory to highlight differences.
- Labels: Add data labels to show exact values or percentages for each segment.
- Sorting: Sort bars in ascending or descending order to emphasize patterns.
- Tooltips: Customize tooltips to display more detailed information when hovering over segments.
6. Advantages of Stacked Bar Charts
- Shows contribution: Clearly visualizes how individual subcategories contribute to the overall category.
- Great for comparisons: Easily compare the totals and the distribution of subcategories across different categories.
- Space-efficient: Combines multiple variables into one chart, making it great for summarizing complex data.
7. Limitations of Stacked Bar Charts
- Hard to compare segments: Comparing the size of individual segments across bars can be tricky, especially if they’re not aligned.
- Overcrowding: With too many subcategories, the chart can become cluttered and hard to read.
- Not ideal for detailed trend analysis: It’s harder to identify small changes or trends over time compared to line charts.
8. Best Practices for Stacked Bar Charts
- Limit the number of subcategories: Keep it simple with a few key subcategories to avoid clutter.
- Use distinct colors: Make sure each subcategory has a unique and distinguishable color.
- Consider a 100% stacked chart for relative comparisons: If you care more about the proportion of subcategories rather than their absolute values, a 100% stacked bar chart works better.
- Add labels or tooltips: This helps users get precise information for each segment without overcrowding the view.
