Previously we discussed the best use case scenarios for some common chart types: bar, line, and pie chart. We also discussed some more advanced and less common chart types: maps and scatter plots. In this post, we are going to go over some more advanced chart types: histograms chart and bullet chart.
1. Histogram Chart
Like a bar chart, a histogram chart allows you to quickly compare information and see highs and lows. You will want to use a histogram when you want to see how your data is distributed across groups.
When to use:
- To see how data is distributed across defined groups or “bins”
Make it shine:
- Explore. Look for numerical measures that can be grouped to create dimensions. Try creating a variety of histograms to help you determine the most useful sets of data. You will want to make sure you create groups that are balanced in size and relevant for your analysis. Examples may include number of employees, age, years in the industry, etc.
- Add a filter. Allow your audience to use filters to drill down into different categories and demographics to explore further.
Figure 1: Here we see sales figures grouped in $20 increments. You can quickly see that a majority of our sales are less than $20 and that we have very few sales that are over $520. Through the use of color, we can see that our profits are good for the $20-59 range, but that less than $20, where most of our sales are have a lower profit. If we had looked at each sale individually, it would have been more difficult to see these trends.
2. Bullet Chart
This chart type is excellent for showing progress against a goal. Essentially, a bullet chart is a variation of a bar chart, but with added features that allow the viewer to easily see progress against a goal. Unlike, dashboard gauges and thermometers, which are similar, the bullet chart can display key information and without taking up a lot of space.
When to use:
- To compare a primary metric, like year-to-date revenue, to one or more other metric, like revenue budget or goal.
Make it shine:
- Add shading or color. By adding color, such as red, yellow, green behind the primary measure, your viewer can quickly understand how performance compares to goals. Shading can also be helpful to give the view more context by showing a natural breakdown, such as quarters.
- Include on a dashboard. When you combine bullet charts with other visualizations, the viewer is able to gain even more insight. You may want to include an association-wide metric and then also show a more granular breakdown.
Figure 2: On this dashboard, we see how year-to-date revenue compares to the revenue budget. In the chart on the left, you can see how each member type is going compared to their revenue budget. The grey shading indicates the quarterly budget. This is helpful as the year progresses to allow the viewer to see not only how the revenue is doing against the yearly goal, but also how revenue is tracking. The chart on the right is a summary of all member types and provides the same quarterly shading for quarter.