The purpose of the Common Industry Specification for Usability - Requirements (CISU-R) is to provide a structure for:

• Defining usability requirements in sufficient detail to make an effective contribution to design and development,
• Defining usability criteria that can be empirically validated subsequently if needed.

Who can use a specification of requirements based on the CISU-R?

A specification of requirements based on the CISU-R may for example be used by individuals with the following roles to accomplish the following objectives:

• Usability professionals and designers in supplier organizations to decide whether usability requirements specified by a customer are realistic, and to plan how to ensure that a product meets these requirements.
  
• Other technical professionals and managers in supplier organizations to decide whether to accept usability requirements.
  
• Usability professionals in customer organizations to include usability in a Request for Proposals.
  
• Other technical professionals and managers in customer organizations to assess if the usability requirements specified by supplier organization meet the needs of the customer organization.

How the CISU-R can be used?

The information in the CISU-R supports communication between the parties involved to obtain a better understanding of the usability requirements.  The communication may be:

• Among members of the development team, to specify requirements for use by the development team.  (In this case the usability requirements may be incorporated into existing documents rather than forming a stand-alone document.)
  
• Between the customer and supplier of a custom product, to define specific customer requirements.
  
• Between a range of potential customers and a supplier of an off the shelf product, to define diverse requirements.

Conformance

There are three levels of compliance to the CISU-R: 

Level 1: Context of use
Context of use provides information on intended use. To achieve Level 1 compliance, usability requirements shall specify

1. The stakeholders
2. The intended user groups.
3. The main goals for each user group.
4. The intended computing or other technical environment.
5. The intended physical and social environments.
6. Scenarios of use specifying how users carry out their tasks in a specified context.
7. Any prerequisite documentation or training materials.

The following information should be provided:

1. Which measures in Level 2 could be used to measure usability.

Level 2: Usability measures.
Usability measures provide evaluation criteria for defined scenarios of use of the product, against which the usability of the product can be evaluated. For Level 2 compliance, appropriate measures shall be specified that may include:

1. Performance measures, such as effectiveness and efficiency of achieving user goals.
2. Satisfaction measures using an established questionnaire.

Level 3: Test method.
The test method specifies how it is planned to evaluate that the usability requirements have been met.