Stakeholder Requirements Use Scenario

Use scenario One basic structuring mechanism for discussing capability requirements is the operational or use scenario. Scenarios provide an excellent method for exploring requirements with stakeholders Stakeholder requirements use the notion of a scenario as a means of establishing a framework in which meaningful dialogue can take place.

Use Scenario The scenario encourages the stakeholders to think about the job that they are doing and how they would like to do it. Once the scenario has been agreed, individual requirements can be generated to define precisely what the stakeholders would like to be able to do at each point in the scenario The purpose of creating a scenario is to promote understanding and communication. A scenario is not itself a requirement; it is rather a structure for elicitation of requirements.

Use Scenario A scenario is the sequence of results produced (or states achieved) through time for the stakeholders. a use scenario may be represented as a hierarchy of goals and represents the capabilities provided by the system to the stakeholder – without saying how to provide them.

Scenario is seen to be beneficial for the following reasons: - enables stakeholders to step through operational use; - missing steps can be found; - different stakeholders can have different scenarios; - time constructs can be identified

The basic question to ask the stakeholder is: ‘What do you want to achieve’? ‘What state do you want to be in’? If the system is completely new stakeholders need to use their imagination and postulate what they want to happen or achieve at each step.

Goal Hierarchy Procedure:

Example

The example covers all the aspects of the trip starting with loading the boat on to the car, getting ready to sail, sailing and returning home. The scenario: - follows a time sequence; - its nodes are high-level capabilities; - shows alternatives; - shows periodic repeated behavior; - shows where sequence is not important (parallel branches); - shows exceptions.

missing capabilities: - able to transport the loaded boat - able to launch boat

Constraints A constraint is a type of requirement that does not add any capability to a system. Instead, it controls the way in which one or more capabilities are to be delivered. For example, consider the following: 'A customer shall be served within 15 minutes of placing the order'.