Column charts are great to show change over time because it’s easy to compare column lengths. Column charts can be used to plot both nominal data and ordinal data, and a stacked column chart can be used instead of a pie chart to plot data with a part-to-whole relationship.
Difference Between Clustered Column Chart and Stacked Column Chart
The column chart and the stacked column chart both display data using rectangular bars where the length of the bar is proportional to the data value. However, in the column chart, data values are displayed side-by-side whereas in the stacked chart, they are stacked one over the other.
Stacked column charts work better when you want to compare the whole and the part to whole relationship. It’s difficult to compare columns that don’t start at the same baseline. If the focus of your chart is to compare multiple parts across all your totals with each other, go for small multiples instead.
Let’s understand the usage of these charts with an example.
Say you want to compare your region-wise sales for 2012. A column chart can easily facilitate that comparison.
But what if you also want to show the quarterly contribution from each region? In this scenario, the stacked column chart is very helpful, as it can facilitate both comparison as well as part-to-whole relationship.
From the stacked column chart above, you can not only compare the sales of each region but also analyze the breakdown of each regional sales into its constituent quarters (part-to-whole). The stacked chart is effective as it can visually aggregate the parts of a whole.
Grouped Column Vs Stacked Column Chart
Data interpretation using a stacked column chart becomes difficult when you want to compare the constituent parts of each entity across the various entities. Try comparing the 2nd Quarter sales across the regions from the above chart!
To facilitate such an analysis, we can use the grouped column chart.
When several column charts come together and are placed side-by- side to form individual groups, they are called grouped column charts.
In the grouped column chart, all the columns have the same baseline and thus it is much easier to compare the heights of the individual columns.
Furthermore, to make the analysis easy, bring those columns closer that are to be compared. The closer the columns that are to be compared, the easier it gets to compare them.
In this chart, we have brought the quarterly sales of each region closer so as to form four groups―North, South, East and West. You can easily compare the sales of North across the four quarters from this chart.
On the other hand, in this chart, the sales of the regions North, South, East and West form four groups―Quarter 1, Quarter 2, Quarter 3 and Quarter 4. It is easy to compare the sales of each region within a group (quarter) due to their proximity with one another.
To sum up, while the column chart can be used to facilitate all comparison-based analysis, it is better to use the stacked column chart when you want to show part-to-whole relationship (along with comparison).
PS: We have more posts that talk about charting best practices. You can check them out here.