846 ITU‐T's Technical Reports and Specifications 6 Conclusions This Technical Report collects a number of indicators that have been developed for cities by global, national, regional, academic and company stakeholders. The analysis evidenced the broad set of perspectives and approaches that exist in this field, but most importantly and common to all, it showed the importance attributed to measuring, monitoring, and learning from ICT usage in smart sustainable cities. The content and supplementary information contained in this Technical Report allows the following general reflections: Although the specific categorization used differs between indexes, frequently used categories are economy, environment and – to some extent – governance. These are areas that have been recognized to be at the core of SSC strategies. The social aspect of sustainability is addressed in different ways by specific sets of indicators. Some have a main category for social aspects and add sub‐categories, others do not include the social as an individual category, but instead use several categories that are related to social aspects. Despite the specific and sometimes diverging approaches to measuring the role of ICTs in smart city contexts, the sources reviewed confirmed the relevance of the key dimensions and sub‐dimensions identified by the FG‐SSC for the development of SSC KPIs. They also suggest the appropriateness of looking into ICT aspects, environmental sustainability, productivity, quality of life, equity and social inclusion, and non‐ICT infrastructure development, as crucial components of smart sustainable cities. The comparative review conducted provides a valuable background for the discussions held by the members of ITU's FG‐SSC, particularly for the exchanges that took place among the members of Working Group 3 focused on KPI and metrics. The review also helped to inform, complement and substantiate the development of the FG‐SSC series of KPIs Technical Reports and Technical Specifications, specifically “Technical Specifications on overview of key performance indicators in smart sustainable cities”, “Technical Specifications on key performance indicators related to the use of information and communication technology in smart sustainable cities” and “Technical Specifications on key performance indicators related to the sustainability impacts of information and communication technology in smart sustainable cities”.