Types of Hierarchies in OBIEE 11g

OBIEE supports various kinds of hierarchies. OBIEE 10g support Level-based, value-based hierarchies but OBIEE 11g supports two more hierarchies. Here is the definition for that

Level-based	Consists of one or more levels. For example, a Time hierarchy might have levels for Year, Quarter, and Month.
Value-based	Consists of values that define the hierarchy, rather than levels. For example, an Employee hierarchy might have no levels, but instead have names of employees who are managed by other employees. Employees can have titles, such as Vice President. Vice Presidents might report to other Vice Presidents and different Vice Presidents can be at different depths in the hierarchy.
Ragged	A hierarchy in which all the lower-level members do not have the same depth. For example, a Time hierarchy might have data for the current month at the day level, the previous month’s data at the month level, and the previous 5 years’ data at the quarter level. This is also known as an unbalanced hierarchy.
Skip-level	A hierarchy in which certain members do not have values for certain higher levels. For example, in the United States, the city of Washington in the District of Columbia does not belong to a state. The expectation is that users can still navigate from the country level (United States) to Washington and below without the need for a state.