IBM Cognos User Manual page 59

Level Derived Indirectly
When a level is derived indirectly, the source is not related to the level, but is
related to descendants of the level. The default color is light yellow.
For example, this source contains a column that provides category values for the
unique level Product No., but no columns for the ancestor levels. Product Type
and Product Line may be levels manually created by the modeler, or their category
values may come indirectly from columns in other data sources.
Level Derived From a Source with Missing Columns
When a level is derived from a source with missing columns, it cannot take its
values from the source because the source is lacking columns for the ancestor
levels, and a missing level, by definition, is not unique. The source does not
contain enough data to map column values to a level without knowing the entire
context. The default color is red.
For example, this source contains a column that provides category values for the
level Product No., but not for the ancestor levels Product Line and Product Type.
The context of the Product No. categories cannot be determined because the level
was not declared unique.
Example - Verifying the Scope of Data Sources in a Sales Model
You want to verify the scope of your data sources in a basic sales model.
The data source is as shown. The GO Data Warehouse columns of Product Line,
Product brand, and Region provide category values for the top levels in the
Products, Product Brand and Retailers dimensions, and so on.
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Chapter 3. Data Sources for Your Model