I’ve only just discovered the bullet chart, I’ve had no need to create one until very recently. It’s a great way to compare values, such as a year on year change. However the bigger benefit is comparing year on year while also comparing with another value. For example a budget / target number. It enables seeing how a number is tracking year on year and vs budget in one simple to view chart.
Tableau has the bullet chart in the ‘Show me’ button. However I have found it doesn’t always work correctly. Therefore this article gives a brief description of how to create one.
I am keeping the data very simple, a two field dataset containing [Date] and [Value]. Each month for 2 years, 2010 and 2011, has a value. The Value field could represent an order count, could be profit, could be sales, etc. To create the bullet chart I will create two calculated fields. One to show all values for 2010 and the other to show all values for 2011.
The formula for the 2010 only is:
[2010 values]: IF YEAR([Date] ) = 2010 THEN [Value] END
Clearly 2011 is almost the same:
[2011 values]: IF YEAR([Date] ) = 2011 THEN [Value] END
Select these two new fields in Tableau desktop (ctrl – click to select multiple) then click Show Me. The bullet chart option should appear. Click on this and you should have bullet chart.
If not it’s simple enough. Put [2011 values] on the Columns shelf and [2010 values] on the Detail shelf.
Tableau should make this a bar chart. To create the bullet chart add some reference lines.
We can use a reference line to show the total for 2010. We can also use another to show the percentiles of 2010.
To add a reference line right click on the X axis and select Add Reference Line. Create the reference line for the comparison value, in this case 2010, the same as within the below image:
Next add another reference line for the percentiles. By default Tableau sets these at the 60th and 80th percentile but choose whatever values are most suitable for your data. Create the percentiles as follows, also using the reference line technique:
We could easily add another reference line to show the 2011 Budget. If we had that data in the data source then follow the same steps as adding the 2010 total. An alternative would be to load as a constant, should the target be a constant – for example if your target is 100%.
A bullet chart is far more informative and simple to read than any gauges or dials found in some dashboard software. It’s also very simple to enhance. Maybe the business sells a range of different products – just add the product to the Rows shelf to compare the year on year for all products in the same chart.