Linked Attributes

In principle, DEXi’s multi-attribute models have a strict tree structure: attributes are structured so that there is exactly one path from each aggregate attribute to the root of the tree. This means that each attribute (other than the root) influences exactly one parent in the tree. Sometimes, this is not enough and we wish to introduce attributes that influence more than one parent. In other words, we wish to create attribute hierarchies (directed acyclic graphs) rather than ordinary trees.

For this purpose, DEXi version 2.0 introduced the concept of linked attributes. The idea is that whenever there are two attributes in the tree that have equal names and equal scales, and at least one of them is basic, they are declared ‘linked’ and they ‘logically’ represent a single attribute. Attribute linking is done automatically by DEXi, but only when explicitly enabled in Settings/Advanced. By default, linking is disabled and equally named attributes are considered different.

This concept allows that DEXi’s trees still retain their basic tree structure. In tree displays, linked attributes appear separately, so the tree structure is preserved - it is only that linked attributes are represented by special symbols: in Tree Views and with italic letters in reports. On the Options Page, however, any ‘chain’ of linked attributes appears only once, so there is no need for duplicate data entry. Linked attributes are also properly handled during the evaluation and on the Evaluation Page.

Recommendation

Attribute linking works only when enabled in Settings. In that case, it is done automatically while you edit your model on the Model Page. As this may appear confusing, you may temporarily disable linking. When enabled again, your links will be restored automatically.