We have all experienced data inconsistency problem in TM1, or the summary data is not equal to the aggregated value of all bottom level data. There are mainly two reasons, the one is that feeders are missed, which probably occurs very often. The other is duplicated parents within the single hierarchy, which is not very easy to identify. It could happen when hierarchy is relatively big, and the TI process cannot grantee avoiding multiple parents. This document is intended to make sample cases to explain these issues with respect to multiple parents.
Illegal multiple parent hierarchy
Please see dimension below
Child 2 is assigned both parent1 and parent 2. This will result in double counting
The total is actually wrong, as Child 2 is aggregate twice.
Legal multiple parent hierarchy
However, there will be no problem if we weight Child 2 50% for parent 1, and 50% for parent 50%.
Alternate hierarchy (with multiple parents)
A child can have more than one parents when dimension is with alternate hierarchy, please see sample below.