ISO/IEC 15026-3:2011 specifies the concept of integrity levels with corresponding integrity level requirements that are required to be met in order to show the achievement of the integrity level. It places requirements on and recommends methods for defining and using integrity levels and their integrity level requirements, including the assignment of integrity levels to systems, software products, their elements, and relevant external dependences.
ISO/IEC 15026-3:2011 is applicable to systems and software and is intended for use by:

• definers of integrity levels such as industry and professional organizations, standards organizations, and government agencies;
  
• users of integrity levels such as developers and maintainers, suppliers and acquirers, users, and assessors of systems or software and for the administrative and technical support of systems and/or software products.
  

One important use of integrity levels is by suppliers and acquirers in agreements; for example, to aid in assuring safety, economic, or security characteristics of a delivered system or product.
ISO/IEC 15026-3:2011 does not prescribe a specific set of integrity levels or their integrity level requirements. In addition, it does not prescribe the way in which integrity level use is integrated with the overall system or software engineering life cycle processes.
ISO/IEC 15026-3:2011 can be used alone or with other parts of ISO/IEC 15026. It can be used with a variety of technical and specialized risk analysis and development approaches. ISO/IEC TR 15026-1 provides additional information and references to aid users of ISO/IEC 15026-3:2011.
Assurance cases are covered by ISO/IEC 15026-2. ISO/IEC 15026-3:2011 does not require the use of assurance cases but describes how integrity levels and assurance cases can work together, especially in the definition of specifications for integrity levels or by using integrity levels within a portion of an assurance case.