Diverging bar chart is a set of bars that are extended into different directions from a baseline. One group of values are displayed to the right of the baseline, second group – to the left. Diverging bar charts are usually color coded to differentiate these groups.
Diverging bar chart is used for comparing two groups of series. If there are multiple contributions for every side it is useful that you can see every component both as a part of a whole and a part of the particular side.
Diverging bar charts are commonly used for profit and loss analysis, budget allocations, election results, customer satisfaction and survey analysis.
The essential part of the diverging chart DNA is the coloring. Especially if it’s a stacked diverging bar chart. Left and right side of the chart (related to the baseline) should be colored in different hues and single bars differ in lightness or saturation of the color. Also consider accessibility of colors. You can learn more about it here.
If there’s a neutral category in surveys, it can be a challenging task to visualize it properly, as usually it is placed in the middle, and the bars in diverging chart are usually placed around the baseline. There are several solutions to this:
– place the neutral category next to the baseline to the positive or negative side, separating it with the color;
– divide the neutral category between two series, using the same color for both of them;
– add an additional chart for neutral category only;