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User Requirements Principles

The highest level expression of user requirements for a capability is the Single Statement of Need.
The most detailed expression of user requirements are the individual requirements and constraints described within a User Requirements Document - a smaller set of Key User Requirements are highlighted from the individual requirements.

What are user requirements ?

User requirements define the ‘gap’ between the existing capability and the required capability. They are the outcomes, effects and services that the user needs to achieve or deliver through deploying or exercising the capability within an operational environment or process.

User requirements are not expressed in a way that anticipates a particular solution being selected. They are expressed using terminology specific to the relevant applied Concept or Concept of Employment (CONEMP) for the capability.

Interoperability requirements should be addressed as an integral component of the capability need, not as an addendum. For further guidance see Interoperability for CIS.

All user requirements for any one capability must be recorded in a User Requirement Document (URD) that is unique to that capability.

Each requirement must be traceable to its user(s).

What is the Single Statement of Need ?

The Single Statement of Need (SSON) is a short explicit statement of a capability need identified from a capability audit:

It records a conclusion drawn from a capability audit.
It summarises the description of the need for management purposes.
It sets the scope of a single URD.
It helps to keep the URD correctly focussed.

The SSON should:

Be short – ideally one sentence, never more than a single paragraph of four sentences.
Have nouns and action verbs drawn from the relevant CONEMPs, capability taxonomy and the analysis that identifies the capability gap.
Be focussed – enough to uniquely characterise one capability gap.
Be unclassified – if possible.
Not be so detailed that it is likely to require amendment as a consequence of trade-off activity.
Not be quantified – unless the statement is meaningless without quantification.

What are Key User Requirements ?

Key User Requirements (KURs) are a sub-set of requirements selected on merit from Part 3 of the URD.

KURs have the following characteristics:

They are key to the achievement of the operational need.
They identify the essential core characteristics of the user need.
They are of particular interest to management.

What are Constraints ?

Any other needs of the users and stakeholders must be reflected in the characteristics of the requirement.

Constraints are typically the characteristics that relate to:

Safety, Environment and Sustainable Development
Security
Other Policy and Directives.

Constraints must be captured in the URD.

Change History

1 July 2008: Link to CIS Interoperability updated.