# A Comprehensive Survey on the Societal Aspects of Smart Cities
## 4 Ranking Smart Cities  
Smart cities are increasingly being created worldwide as governments incorporate smart technologies into their action plans to address urban issues. Therefore, it has become essential to have a way to measure a city's smartness to evaluate its performance, guide future development, and serve as a metric of a country's advancement on the global stage. Due to the lack of consensus on the definition of a smart city, various methods of measuring a city's smartness exist. Although these methods may be slightly incompatible with each other, they are not necessarily incorrect. They simply measure the aspects that the ranking creator deemed most relevant, and by analyzing the different ranking systems, it may be possible to establish a unified and standard ranking system.  
The diversity of definitions of what constitutes a smart city stems from both the evolution of the field and from the priorities of the author. As the technology, the practical and theoretical knowledge of smart cities, and what became possible to achieve with them increased, it also increased the scope of the definition of a smart city and the number of dimensions in which to apply them. This rapid development can make it so that previous research can become outdated before it has the opportunity to be implemented. Additionally, implementing a smart city is a complex process, made more difficult by the need to integrate the disparate systems and their infrastructure across all dimensions of a smart city, as well as having to take into account the needs and wants of the various stakeholders and needing to make these advances available to all the population of the city [298]. Conversely, by having many definitions, it is possible to explore diverse approaches, techniques, and technologies in diverse environments.  
One of the initial goals of smart technologies was to improve efficiency. Therefore, ranking systems that measure the extent to which the efficiency of a city has improved with the introduction of these technologies provide a clear and direct way of assessing smartness. However, as shown in [299], where researchers analyzed the performance and efficiency of thirty-two Chinese cities as ways to evaluate smart city implementation (SCI), they found that although they can be used somewhat to guide development and provide historical context, there was no correlation between high efficiency and high smartness of a city or vice versa. Measuring efficiency is best applied to assessing the impact of smart technologies in specific objective areas, such as energy [300] or ecology [301], rather than evaluating overall city smartness.  
This occurs because the human dimension cannot be ignored, and the impact smart technologies have on aspects such as culture, quality of life, health, or education cannot be measured solely by efficiency. Various methods have been proposed to evaluate the smartness of cities, taking a more comprehensive approach to consider all aspects [302; 303; 304]. However, regardless of their source (e.g., academic, governmental, or private companies), no measuring system has been found to be without gaps in their evaluation [305].  
Therefore, no standard method of ranking smart cities currently exists. While research continues on this front, it may be wise to consider that a standard method of ranking might not be possible or may be too complex to create and use. Even if one is created,methods that focus on just one or a few complementary elements of a city's smartness can still be very beneficial. As stakeholders have specific interests to promote (e.g., economy, security, or energy), they need only to rank those factors that affect their interests. Therefore, instead of a single all-encompassing standard ranking, each stakeholder could use a ranking method tailored to their interests, and a global picture of the smart city's status can then be determined by combining the output of each method [306].