Bullet Graphs Made Easy

by Vicky Lozovsky

Quite often I get requests to duplicate a particular graph using WebFocus Graph packaging. Some requests are simple and others really test the capabilities of the graph engine. Such an example is a bullet graph, which was new to me at the time.

Luckily, the assignment was presented to me in the most effective way, a complete design specification, where the graph image had all the components labeled and identified. See Figure 1. 

Figure 1

A bullet graph was developed by Stephen Few and serves as a replacement for dashboard gauges to communicate key performance indicators. It is a variation of a bar chart, which features a single measure (2005 YTD Revenue in Figure 1) compared to another measure, usually called a target (vertical marker in Figure 1). The bar is displayed in the context of qualitative ranges (three shades of gray), such as poor, satisfactory, and good.

It is recommended to use varying intensities of a single hue when displaying qualitative ranges to make them distinct for those who are color-blind. Other advantages for using variations of a single hue is to restrict the use of colors to a minimum or when using grayscale print media.

After reviewing the design specification carefully, I was ready to build a bullet graph. My first step to building a custom graph (not part of default graph library) is to identify all the components and map them to appropriate properties/methods available in the WebFOCUS graph engine. Once every component has been identified, we can start building the graph.

1. Begin by creating a horizontal bar chart. Note: Design of the bullet graph can also be oriented either horizontally or vertically. Use a horizontal bar chart for horizontal orientation and a vertical bar chart for vertical orientation. Plot the measure on a graph (For example, revenue) and change the color of the riser to black.
2. Change the size of the graph to accepted dimensions (Figure 2).
3. Change the width of the bar (Figure 3).
4. Add the target marker. To accomplish this, create a Y-Axis reference line (Figure 4).
5. Add qualitative ranges. Use alternate formatting regions on the Y-Axis to accomplish this. This would produce various sections on the background and allow setting custom color for each (Figure 5

The result is a graph that provides a richer data display using much less space. With the steps I outlined above, you can build a bullet graph using a rich Chart Editor in Advanced Graph Assistant tool, available in Release 760 or higher.