Drilling increases or decreases the level of document detail by changing the display of dimension members. Because drilling is customizable, the term drilling can mean almost hierarchical navigation prompted by double-clicking a dimension label.
You can customize drilling using three options:
Drilling options specify the drilling result set.
Expand on Drill specifies whether the drilling result set replaces or augments the currently displayed dimension members.
The Selected Member data display option specifies whether the drilled member is included in the drilling result set.