When would a radar chart be more appropriate than a stacked bar chart?

A radar chart is particularly useful when you want to visualize multivariate data in a way that allows for easy comparisons across different categories or groups, especially when those groups might have similar values. When the measures across the different groupings are similar, a radar chart effectively highlights slight variations because it allows each category's value to be represented as a point on a radial axis. This format visually juxtaposes the categories against each other, making it easier for the observer to spot small differences that might be missed in other chart types.

In contrast, a stacked bar chart tends to aggregate values in a way that can mask those smaller differences, particularly if the absolute values are close to each other. The stacked nature of the bars can make it difficult to discern subtle variations between categories, thereby making a radar chart the more suitable option for this specific need.