Activity: Manage Dependencies

The Requirements Management Plan defines the attributes to be tracked for each type of requirement. The most important attributes are Benefit (from the stakeholders' perspectives), the Effort to implement, the Risk to the development effort, the Stability (likelihood to remain unchanged), and Architectural Impact (is it architecturally significant) of each requirement.

The Benefit and Stability are set by the System Analyst, in consultation with the stakeholders. Effort and Risk are set by the Project Manager, in consultation with the Software Architect. Architectural Impact is set by the Software Architect.

Unstable requirements with high risk, high effort, or high benefit should be flagged for more analysis. Low benefit requirements with high effort, risk, or instability should be flagged for potential removal.

Below is an example of a set of features of the RequisitePro tool as found in the Vision document, together with requirements attributes for each feature. Benefit refers to customer opinion, and effort is input from the developers.

Features	Benefit	Effort	Risk	Architecture Impact	Stability
FEATURE1: Save and restore sort and filter criteria	Med High	Low	Low	Low	High
FEATURE2: Ability to save a RequisitePro document as a Microsoft® Word® document.	Med High	Low	Low	Low	High
FEATURE3: Ability to see deleted requirements in a view window.	Medium	Med High	Medium	Low	Medium
FEATURE4: Support for Currency datatype attributes.	Medium	Medium	Med Low	Low	Medium
FEATURE5: Support the "All" document type (provides an easy way to define common attributes across multiple document types).	Med High	Medium	Medium	Low	Med High
FEATURE6: Ability to select requirement in a view and GoTo in Word document.	Med High	Medium	Medium	Low	Med High
FEATURE7: Display a requirement's attribute in the text of the requirement's document.	Medium	Medium	Medium	Low	Med High
FEATURE8: New project wizard	Med High	High	Med High	High	Medium
FEATURE9: Fast creation of a requirement (avoid the requirement dialog on creation).	Med High	Med Low	Med Low	Low	High
FEATURE10: AutoSave of a project (project archive).	Medium	Med Low	Medium	Low	Medium
FEATURE11: Change one or more attributes for a selected set of requirements.	Medium	Med High	Medium	Low	Medium
FEATURE12: Ability to clone a project's structure to allow users to easily create new projects from old projects.	High	Medium	Medium	Low	Low
FEATURE13: Performance enhancements for printing, requirement identification.	Med Low	Med High	Medium	Low	Med High
FEATURE14: Microsoft® Windows95® Port.	High	Medium	High	High	High

Say that based on what you know about resources, you have determined that only two-thirds of these features can be included in a first iteration. You need to stabilize the architecture, so features 8 and 14 must be implemented early. However, feature 8 has only Medium stability - so you need to work with the stakeholders to reduce this to Low as soon as possible.

Feature 13 is only Med Low benefit, but has Med High effort, so this may be flagged for potential removal.

You also know that it is critical that you can deliver something at your deadline, so you want to avoid high effort features, especially if combined with instability. Thus you may decide to exclude features 3, 11, and 12.

Establish and Verify Traceability

The Requirements Management Plan defines how requirements types are traced to other artifacts. The System Analyst must establish the required traceability, and periodically use traceability reports to ensure that traceability is maintained in accordance with the Requirements Management Plan.

Manage Changing Requirements

Requirements changes are managed in accordance with the Requirements Management Plan. Some additional guidelines are as follows:

Re-assess Requirements Attributes and Traceability

Even if a requirement hasn't changed, the attributes and traceability associated with a requirement can change. The System Analyst is responsible for maintaining this information on an ongoing basis.

Manage Change Hierarchically

A change to one requirement may have a "ripple" effect that affects other related requirements, design, or other artifacts. To manage this effect, you should change the requirements from the top down. Review the impact on the Vision, then the Use Case Model, Design Model, and End-User Support Material. To manage the impact of requirements change on the test effort, review the related information in Activity: Define Traceability and Assessment Needs. Traceability reports are useful in determining the potentially affected elements.