A disadvantage of a stacked column chart is:
A) it does not include all the values of the variable
B) It cannot be used to compare relative values and quantitative variables for the same category
C) it has difficulty perceiving small differences in areas
D) used when many quantitative variables need to be displayed.
The correct answer and explanation is:
The correct answer is C) it has difficulty perceiving small differences in areas.
A stacked column chart is commonly used to represent data that is broken down into multiple subcategories within each main category. Each column represents the total for a given category, and the segments within each column represent different subgroups. While this is useful for understanding the total and how subgroups contribute to that total, there is a significant disadvantage.
When comparing stacked columns, it can be difficult to perceive small differences in areas, especially when the segments of the columns are very close in size. The total height of the column may be easy to see, but the smaller segments within the column might be hard to distinguish accurately, especially if they are very narrow. This can make it challenging to compare the individual subgroups across different categories, especially when there are many categories and the differences between them are subtle.
Additionally, as the number of segments increases, the problem becomes even more pronounced. Larger segments on the bottom can obscure smaller segments on top, which further complicates comparison. It is not uncommon for users to misinterpret the relative contributions of subgroups when the differences in size are marginal.
Another issue is the distortion caused by stacking. Since each segment starts from the top of the previous one, comparisons between segments of different columns may not be as accurate as they would be if the segments started from a common baseline. This can lead to the misinterpretation of data, especially when precise values are needed for analysis.
Therefore, while stacked column charts are effective in showing total values and overall proportions, they should be used carefully when there is a need to make precise comparisons between small differences.