366 CHAPTER 14 Modeling Cross-Cutting Relationships with Allocations contrast : Signal. Allocation between item flows or item properties is best represented by an allocation matrix, as shown in Figure 14.20. In the example shown in Figure 14.20, note that the logical data model is independent of the physical data model, and thus the types (conveyed classifiers) of each item property are different. 14.10 EVALUATING ALLOCATION ACROSS A USER MODEL The integrity and completeness of the allocation relationships is largely dependent on the system's stage of development. Since allocation may be used as an abstract prelude to more concrete rela- tionships, the quality of allocation at a given point in time is assessed with respect to the system development method or strategy being employed. 14.10.1 Establishing Balance and Consistency The quality of the model can be assessed in terms of the completeness and consistency of the allocation relationships and the overall balance of the allocation as described next. Completeness and consistency can be evaluated using user defined rules or constraints. In func- tional allocation, for example, allocation of a package of activities is said to be complete when each