Bullet charts were added to Tableau in version 5.1. They are an original idea designed and advocated for by Stephen Few, at the University of California at Berkeley. The bullet chart is intended to enable easy examination of attainment relative to a target for categorical items.
According to Stephen's original specification, "The bullet graph was developed to replace the meters and gauges that are often used on dashboards. Its linear and no-frills design provides a rich display of data in a small space, which is essential on a dashboard."
I have shown the standard Tableau bullet chart and a wide array of variants in our public training course. Based on extensive attendee feedback, I will share how just a few minutes spent enriching your bullet charts will yield powerful enhancements for your dashboard audience.