A simple bar chart with two series for pairwise comparisons of categorical variables.
- In a bar chart with two series you have three goals: simplify pairwise comparisons, clarify how the more relevant series ranks categories and communicate the overall shape.
- The more series you add the harder is to fulfill those goals.
- When possible, move the legend to the plot area.
- Set series overlap to zero to remove the unnecessary gap between series.
- The default gap width between categories is too large and can be reduced. A value between 50% and 100% should be fine for most cases.
- Use pale colors with large charts, and make sure both series are both equally salient, unless you want to emphasize one of them.