Scope Considerations

A single instance of the Goal-Service Model should be created to cover all business domains within the scope of the project. Given that subject matter experts may be experts in a specific business domain, an iterative approach can be used to focus on one domain at a time to make interviews or work sessions more efficient.

During Goal-Service Modeling interview or work sessions, consider the knowledge areas that the subject matter experts can speak to. For example, it may be possible to capture some initial statements of non-functional requirements in parallel with this task. This can provide valuable input into other more detailed requirements gathering sessions.

Goal Modeling Considerations

In the same way that goal modeling can be performed either in a UML environment (see Guideline: Business Goal) or in a requirements management environment (such as Rational RequisitePro) the modeling of relationships between services and goals can be performed in either environment. However, it is important to ensure that all leaf-level goals are supported by one or more services and so traceability information is critical. One way to present the model for review is to represent it in a tabular form, as shown below, which clearly identifies any goal unsupported by services.

Estimation Considerations

Plan for one iteration of Goal-Service Modeling for each business domain that falls within the scope of the project. The level of effort for each iteration of the Goal-Service Model can be expected to fall in the range of 12 to 40 hours. This will complete the Goal-Service Model to the first elaboration.

For each business domain, in order to complete the Goal-Service Model to the first level of elaboration, estimate:

Note: the second elaboration of the Goal-Service Model is completed during Service Exposure Decisions, which may lead to minor updates to the Goal-Service Model as a result of the validation and completion of the mapping of goals to services. This can potentially add a small number of additional goals or sub-goals to address gaps found during the mapping process. Effort for the second elaboration is considered to be part of the Service Exposure Decision task.

The duration and the amount of effort required to develop the Goal-Service Model will vary depending on:

• Complexity of goals for the business domain
• Number of functional areas within the business domain
• Quality and completeness of the input work products (i.e. list and description of high level goals)
• Experience of team (in technique and industry)