ISO/IEC TS 25025:2021

This document defines quality measures useful for requirements and evaluation of IT service quality in terms of characteristics and sub-characteristics defined in ISO/IEC TS 25011. This document contains a basic set of quality measures for each characteristic and sub-characteristic. This document does not assign ranges of values of the quality measures to rated levels or to grades of compliance. Such values are defined based on the nature of the IT service, and so depends on factors such as category of the IT service or users' needs. Some attributes can have a desirable range of values, which does not depend on specific user needs but generic factors, for example, service downtime. This document includes, in Annex A, considerations for the selection and application of quality measures. The quality measures in this document are primarily intended to be used for quality evaluation and improvement of IT services during or after the development life cycle. The main users of this document are people carrying out quality requirements specification and evaluation activities for IT services as part of the following: - development: including requirements analysis, design, implementation, testing and deployment during the development life cycle; - quality management: monitoring activities of quality assurance and performing quality control of an IT service; - supply: making a contract with the user for supplying an IT service under the terms of a contract; - acquisition: including IT service selection, when acquiring or procuring an IT service from a service provider; - maintenance: improvement of an IT service based on quality measurement. The relationship of this document to domain-specific IT service quality model and its precedence over this document is determined by the user in a specific context of use.