Comparison Between a Few Groups
For example: Compare differences by race and ethnicity
Consider using: Bar Chart
Bar charts are useful for showing categorical data, such as data by race or by gender, where you are showing comparison between groups. A horizontal bar chart makes it easy for viewers to compare between bars to recognize which bars are longer and which are shorter. Vertical gridlines provide a quick reference to estimating length and compare differences, and labels provide exact percentages or numbers which are particularly useful when comparing between groups with smaller differences.
Comparing Between Many Groups
For example: Compare cities/states, or use disaggregated racial data
Consider using: Column Chart
Column charts are vertical bar charts, and are also useful for comparison between groups, particularly when there are more than seven categories. They are also useful for illustrating ranking across many groups, such as helping users to identify how their city or state compares with other cities and states.
Note that the labels for the categories can be displayed at an angle to maximize space.
Show Gaps and Change Over Time
For example: Show different rates over time for each racial group
Consider using: Trend Lines
Trend lines are a useful way to illustrate change over time. Using markers can help users identify key points on your chart, and different colors for each line makes it visually clear for comparison between different groups represented.
Show Clusters and Gaps Between Groups Over Time
For example: Show distribution between races for different years
Consider using: Dot Plot Graph
Dot Plots are useful for showing distribution comparison between categories, and also show patterns of that distribution. They are efficient for when comparing between groups. One way to highlight differences between multiple groups and to bring attention to particular groups of focus is to change the shape and size of the dots.
Display and Compare Geographically-Related Data
For example: Compare differences between and across states or cities
Consider using: Maps
Maps are used to illustrate differences between geographies and allows users to quickly compare across multiple geographies. Maps can help users contextualize data in a familiar frame of reference and take in multiple data points at once.