The Drilldown Column Chart viewlet has the same functionality as the normal Column Chart Viewlet, with the benefit of being multi-tiered. By clicking on specific columns, the user can “drill down” to levels contained within the one above it. The groups beneath each section are constantly totaled, relative size at all times. Specific values can be seen by hovering over the individual columns. This viewlet can be helpful for comparing multiple levels of data, such as a business park, its buildings, wings, rooms, etc.