More Comparing a Variable Across Groups
Stacked Bar Charts
stacked bar charts
Stacked bar charts display the same data as a contingency table and a side-by-side bar graph.
This type of chart offers a different perspective of a visual comparison between the groups, where the height of each bar totals [latex]100\%[/latex] for that group.
In the stacked bar chart, each bar represents the responses of one group. The height of each color within that bar represents a percentage of a particular response and the combination of all colors represents the total [latex](100\%)[/latex] of all responses within that group. Like the side-by-side bar chart where percentage is plotted along the vertical axis, you cannot make conclusions or comparisons regarding the absolute counts of responses within or between groups.
Rather than showing a different bar for each category, stacked bar charts display sub-categories as segments within each bar. Sometimes the bars represent counts, while others, such as the ones we see in the questions below, display percentages. Each segment represents a percentage of the whole, so it’s easy to see relative differences within a bar. But as segment percentages grow smaller, it can become difficult to estimate them.