Evidence types can naturally relate to each other. The most common evidence relationship is the parent/child relationship where a parent evidence record can have one or more related child evidence records. For example, an income evidence record can have one or more income usage evidence records.
Evidence relationships impact evidence maintenance in a number of ways. The evidence type list for child evidence types is filtered to display only those evidence records that are related to the parent evidence record. Also, validations can be called which check for any evidence relationship requirements. For example, it may not be possible to remove a parent evidence record if there are any active child evidence records related to it.
Evidence types can have multiple evidence relationships. For example, an evidence type can be the parent of one evidence type and the child of another; this is referred to as a parent/child/grandchild relationship. Also, evidence relationships can be optional. For example, the housing expense evidence type could be in an optional parent/child relationship with the loan evidence type. From a business perspective, certain loans may be directly related to a housing expense, while other loans may be unrelated to housing expenses, such as a car loan.