778 ITU‐T's Technical Reports and Specifications 3.2.2 ICT companies: companies which provide products and/or services with respect to Information and Communication Technologies. 4 Abbreviations and acronyms These Technical Specifications use the following abbreviations and acronyms: COP Child Online Protection DSL Digital Subscriber Line EMF Electromagnetic Field GDP Gross Domestic Product GHG Greenhouse Gas GIS Geographic Information System ICT Information and Communication Technology IDI ICT Development Index ISO International Organization for Standardization ITU International Telecommunication Union KPI Key Performance Indicator LAN Local Area Network SSC Smart Sustainable Cities UN‐Habitat United Nations Human Settlements Programme WHO World Health Organization 5 General principles for Key Performance Indicators (KPIs) for ICT in a city context The selection of KPIs is based on the following principles: Comprehensiveness: The set of indicators should cover all the aspects of SSC. The indicators of evaluation should be aligned to the measured subject, i.e., ICT and its impact on the sustainability of cities. The index system should reflect the level of general development in a certain aspect. Comparability: The KPIs should be defined in a way that data can be compared scientifically between different cities according to different phases of urban development, which means the KPIs must be comparable over time and space. It should also be possible to extend and amend the set of KPIs according to the actual development. Availability: The KPIs should be quantitative and the historic and current data should be either available or easy to collect. Independence: The KPIs in the same dimension should be independent or almost‐orthogonal i.e., overlap of the KPIs should be avoided as much as possible. Simplicity: The concept of each indicator should be simple and easy to understand. Also the calculation of the associated data should be intuitive and simple. Timeliness: The ability to produce KPIs with respect to emerging issues in SSC construction.