Conveying clear data efficiently
Stephen Few, who is a data visualization expert, came up with this chart, and, if you want to dig into the details, make sure to read his design specification document. Now, if you’ve read it, you can see that Few’s main motivation was to make a chart that is more efficient than a gauge chart. So, let’s start with having a look at a comparison between a gauge chart and a bullet chart. We’ll create a gauge and a bullet chart, each for Sales in 2019, together with our comparative measure, which, in this case, is our goal to reach $1 million.
As you can see above, a gauge chart with an arc really takes up space compared with the bullet chart that has a more linear design. Of course, having that space also means that you can easily show the achieved sales of $717,032 that the needle is pointing at, which would have to be added somewhere to the bullet chart.
Shaded segments let you know how well you’re doing
For both the gauge chart, as well as the bullet chart, we often want to add colored segments behind them to indicate how well we are performing, such as good, satisfactory and poor. For this, I’m going to go with the suggestion from Few to use intensities of a color to create shaded segments rather than different colors to avoid issues for people who are color blind.
I’ll add limits to these shaded segments at 25 percent (good, a light gray), 25 percent (satisfactory, a slightly darker gray) and 50 percent (bad, a dark gray). This means that, even if our goal is to reach $1 million in sales, it’s still good to be at $900,000, as that would be well within the 25 percent light gray segment.
Why use a bullet chart?
There might not be much of a difference here, but what I like about the bullet chart compared with the gauge chart is that the bar helps me indicate that we’ve started at $0 in sales and are well on our way to reaching $1 million. For me, this is better, as the gauge chart, with its arrow, only indicates our current sales dollars, not how far we’ve come in making them.
Lastly, what we can do with a bullet chart is to create multiple ones, which can be easily arranged, as they are more space efficient than gauge charts. Here is an example where I’ve done something like a trellis and added more measures.
Now, it’s quite easy to see that we still need to work on our sales and profit. But, we have achieved our goal when it comes to number of customers.
So, the next time you’re creating a KPI dashboard, think first if you should really clutter it up with gauge charts or would it be better to use a more streamlined bullet chart.
Learn more about the advantages and capabilities of bullet charts by watching a Qlik Sense® YouTube video.