Attributes are a very important source of requirements information. Just as every person has attributes (age, hair color, gender), each requirement has a source, a relative importance, and time it was created. Attributes do more than simply clarify a requirement.  If created properly, they can yield significant information about the state of the system. Just as you can run a database query to find all men with brown hair over age 30, given our human example, you can run queries on the status of requirements to find all high-priority requirements from the customer in the last 30 days. [TEL06]

Examples of attributes

Listed below is a partial list of some common attributes and a brief description of their meaning. Some attributes are best described as a number, date, Boolean (true or false) or a text field for entering free format comments. Other attributes can be expressed as lists. For instance, priority type is a list of high, medium, and low; Weekday is a list which includes Monday, Tuesday, and so on.

Source - Person, document or other origin of a given requirement.  This is useful for determining whom to call for questions or for grouping requirements according to the person making the demands.

Priority - Statement of relative importance of the requirement, either to the system (mandatory, critical, optional) or to other requirements (high, medium, low). It is good to track the mandatory or high-priority items as an indication of how well the system will meet the greatest needs or for compliance-related metrics.

Assigned to - Who in the organization is responsible for making sure the requirement is met (person's name or organizational name).

Comments - Reviewer's or writer's comments on a requirement.

Difficulty - An indication of the level of effort needed or how hard it will be to implement the requirement (high, medium, low).

Status - Degree of completeness (completed, partial, not started).

Risk - Confidence measure on the likelihood of meeting (or not meeting) a requirement. Could be high, medium, low or the integers one through ten.

Due By - Date the requirement must be provided.

Method of verification - Qualification type to be used to verify that a requirement has been met: analysis, demonstration, inspection, test, and walkthrough.

Level of Test - Describes the verification lifecycle stage at which the requirement is determined to be met: unit test, component, system or product.

Subsystem Allocation - Name of system or subsystem a requirement is to be assigned to (for instance, flight control module, wing assembly, passenger cabin).

Test Number - Identification of a specific test or other method of verification.