Bullet graphs encode a single variable as a bar.
It looks a lot like a bar graph, with just one bar represented. However, a bullet chart adds some extra context that makes it powerful. Most bullet graphs also show a target line and, in the background, some shaded performance levels. Typically bullet charts are included in dashboards because they pack a lot of information into a tiny amount of space.
Examples
CIO Dashboard featuring two sets of bullet graphs
This dashboard contains many graphs and lots of data but notice the bullet charts in the middle and on the right.
Source: Veronica Smith. Retrieved from http://www.ndedataviz.com/chapter-6--data-dashboard-as-evaluation-and-re...
Advice for choosing this method
If you have a target or benchmark, a bullet chart is a good idea. You do not necessarily have to include levels of performance in the background, even though this is the technical definition of a bullet graph. Bullet graphs can also be used outside of dashboards, in more traditional data displays.
Advice for using this method
Performance areas should be in the background and muted in colour because they are supporting but not primary information. Target lines are often red but can be any colour that will sufficiently pop out to the viewer.
Resources
Stephen Few, the inventor of the bullet graph, outlines the design specifications and includes performance areas.
Other ways to compare sets of values
Sources
Few, S. (2013) Bullet Graph Design Specification. Perceptual Edge. Retrieved from http://www.perceptualedge.com/articles/misc/Bullet_Graph_Design_Spec.pdf
'Bullet graph' is referenced in:
Framework/Guide
- Rainbow Framework :
Method