Cities are facing diverse challenges worldwide, both of local and global origin. Some cities are experiencing intensified urban heat [1
] or natural disasters induced by climate change [2
], while others suffer from air and noise pollution due to traffic and industrial activity [3
]. These problems often generate or exacerbate social challenges, including poverty, segregation, gentrification, and overpopulation [4
]. All of these phenomena tend to influence the perceived “livability” of cities—that is, the quality of the person–environment relationship, or how well the built environment and the available services fulfill the residents’ needs and expectations. These impacts on livability are usually perceived as negative—although not every city is affected to an equal extent, due to their geographic locations or socioeconomic conditions [5
The term “livability” has become popular mainly thanks to livability rankings and indices aiming to quantify urban quality [6
]. However, in this work, we argue that “livability”—if interpreted appropriately—is more than just a statistical index or marketing tool. By facilitating the evaluation of the person–environment relationship, livability can serve as a useful conceptual and analytical framework to improve the quality of urban life. This evaluation should aim to specifically measure how well the built environment and the available services in a city fulfill the residents’ needs and expectations.
In recent years, two international landmark agreements have focused attention on urban challenges and the high relevance of improving the quality of life in cities: the United Nations’ Sustainable Development Goals (SDGs) and the New Urban Agenda (NUA). In particular, SDG #11 aims for inclusive, safe, resilient, and sustainable cities, while the NUA articulates a number of actions needed to improve cities all over the world [7
]. In the case of the SDGs, there is extensive language about “good health and well-being”, “clean water and sanitation”, solid waste management, air quality, provision of basic services and infrastructure, control of sprawl, and other cornerstones of urban livability. In the case of the NUA, there is even more specific language about “enhancing livability”.
It is important to recognize the challenges of creating more livable cities and to raise awareness amongst citizens and decision-makers about urban issues; however, both the SDGs and the NUA represent only the starting point of any solution for these challenges. While researchers and decision-makers seem to be aware of what goals should be achieved and why, the follow-up question is how to actually achieve these goals. As part of the SDG framework, several UN institutes designed a list of indicators to facilitate the achievement of the SDG targets [8
]. However, these indices predominantly focus on data and quantitative metrics to allow for statistical performance values, instead of addressing how the residents experience living in a given city. For example, SDG indicator 11.2.1 describes the “proportion of population that has convenient access to public transport, by sex, age and persons with disabilities”, where we may need to define first what “convenient access” means to these different groups, ideally followed by the mapping of this accessibility within the city to differentiate where and what types of problems are attributed to public transport. Such a spatially explicit approach could diagnose priority areas for planning actions, and may help to improve the understanding of such problems. We argue that the concept of livability, by focusing on the different aspects of the person–environment relationship, can provide a transferable framework for this purpose. Transferability of the assessment procedure is crucial, as one measure may work in a given city, but may not be a solution elsewhere.
To this end, existing urban quality (or livability) assessment approaches usually do not consider the person–environment relationship at different thematic and spatial scales, especially in a transferable way. Their analyses often focus either on a city or a region, e.g., [9
], or provide frameworks for ranking cities through complex indices, e.g., [6
]. Works in the former group are usually quite thorough, but often not transferable; their direct adaptation to other cities is thereby limited. On the other hand, complex statistical indices for city ranking often ignore spatial aspects, especially regarding the intra-urban variance of the different factors, as well as the varying socioeconomic backgrounds of the residents included in the analysis [13
Hence, in this work we have proposed a methodology for conceptualizing urban livability and its assessment in a systematic way. As a follow-up to the conceptual framework, we designed a survey to inspect the subjective aspects of livability along with the satisfaction of dwellers concerning urban life. Next, we applied regression analysis to our questionnaire responses, which served as an input for relational-statistical learning. We were thereby able to estimate the contribution of each livability factor (individually and combined) in the form of probability values of being satisfied with urban life in a given area. To validate the results of these probabilities we compared our modeled values with the ones from the questionnaire for the city of Vienna, Austria. Overall, by identifying key factors to assess, and by developing a transferable analysis workflow, we have argued that the resulting livability assessment framework can “diagnose” a city by assessing the quality of the person–environment relationship. This approach can thereby help planners to improve urban quality of life more efficiently, and also in line with the objectives of the NUA and SDGs.
2. Challenges of Defining and Assessing Livability
Livability is a widely used term, especially when referring to urban environments, and yet there is no general consensus on how to define it precisely [15
]. The existence of numerous similar and overlapping concepts (e.g., quality of life, well-being, sustainability) makes a consistent interpretation even more challenging [15
]. Livability is one of the main types of quality of life, and refers to an outer quality that can influence inner qualities of life such as life satisfaction [19
]. Quality of life can be interpreted as a multiscale concept that represents conditions of individuals and society [22
], and can be defined according to Glatzer through positive and negative well-being expectations and perceptions [24
]. Moreover, quality of life is also a multidimensional concept that can be interpreted by understanding dimensions of physical, material, and emotional well-being, as well as development (e.g., individual choice or competence) and activity (e.g., work, leisure) [25
To provide a general overview on the variety of available livability definitions, we mainly focused on available literature review studies evaluating a large amount of urban environmental quality-related research, such as the work of van Kamp et al. [15
] who scrutinized conceptual models (both theoretical and empirical) related to livability. The majority of the definitions collected by the authors agreed upon some basic elements of livability: what the urban living environment (both natural and built elements) provides and how it is connected to the individuals, e.g., according to their needs or capabilities, etc. The authors listed livability-related factors such as personal characteristics, community, built and natural environment, or public services, but did not consider their analysis per se, or how the overall livability of a place could be assessed. Van Kamp et al. [15
] concluded that the concepts of livability, environmental quality, and sustainability overlap, because all of them represent different aspects of the person–environment relationship.
Pacione investigated this relationship, emphasizing the subjectivity of the objective environment, and explained that this “[…] perception of the city is represented as a joint function of the objective environmental conditions (e.g., population density, temperature, pollution levels) and the individual characteristics of the person (e.g., adaptation level, previous experience, and time in the city).” [18
] (p. 8). One such personal factor is residential satisfaction, which depends on, among other things, the person’s length of residence in the neighborhood and their socio-economic level [26
]. Besides residential satisfaction, the degree of integration of the individual into society [27
], the hierarchy of human needs [28
], and the individual’s aspiration level [29
] are factors which can affect one’s perception towards the environment.
To represent the highly practical aspects of livability, Young and Hermanson [20
] systematically synthesized current practices in livability improvement and examined overlapping definitions and concepts. The authors analyzed interpretations by local actors, such as associations, governmental organizations, and policy makers, who implement livability-related principles on a daily basis. Their work reflects the relevance and importance of livability in planning [30
The fact that the connection between the environment and the person is bi-directional increases the challenges of livability assessment and improvement even further [21
]. People perceive their environment according to their individual characteristics, but as Pacione [18
] observed, the “[…] built environment can influence the behavior and well-being of people [as well] by, for example, facilitating or discouraging interaction, fostering a sense of identity, or alienating people from their surroundings.” [18
] (p. 12). Once this effect of the built environment is understood, the efficiency of decision makers’ and urban planners’ actions toward creating livable places can be enhanced. Since livability-related improvements are complex, this endeavor requires a firm theoretical basis and assessment of the current situation, as well as cooperation among planners, architects, social scientists, and policy makers [31
Although there is a common agreement that livability is an essential concept in urban planning, assessing livability is still vulnerable to subjective variation among residents. Even if there is a set of (measurable) characteristics that define when a place is livable, these features do not have the same importance for everyone, and even for the same person, the importance varies over time [17
]. Furthermore, even seemingly objective factors are not perceived objectively, and their representativeness, in general, is hard to assess because of their ad hoc nature [22
]. Due to these individual and varying characteristics regarding human needs and the subjectivity of people’s perceptions, one must be careful not to try to over-assert the livability of a given place as an independent objective condition. Obviously, there are objective characteristics of a city (such as crime rates, demographical statistics, infrastructure-related metrics), but they are not directly usable as factors in livability assessment where the goal is to describe the highly contextual relationship between human needs and the functionality provided by the environment, and to what extent these needs are fulfilled. For example, crime rates (provided as official statistics) and the actual perceived safety (relying on subjective perception) can have very different interpretations.
Therefore, we have differentiated between measurable and objective factors in our assessment framework. A factor might be measurable (e.g., perceived safety), but instead of objectivity, our aim was to detect the relevance or perception of that specific factor for citizens on an individual level. In this context, it is helpful to treat cities as complex systems, due to the large number of different sub-systems featuring various spatial and temporal characteristics (e.g., transportation, road network, natural environment, building infrastructure) [33
]. Due to the dynamic nature of cities, it is crucial to consider the spatial and temporal aspects of these (sub)systems in urban analysis, which can be done by using geographic information systems (GIS) in a systematic way. The benefit of GIS is their demonstrated value in collecting, storing, and analyzing data systematically, usually with spatial (and temporal) relations, and also according to thematic groups representing various elements of the urban system (e.g., transportation, urban green, shopping facilities). Moreover, GIS combined with other methods, such as sensor measurements and questionnaires, can provide a powerful methodology for assessment and analysis, e.g., [35
]. By visualizing the results of various GIS analyses in the form of maps, we can support planners and decision-makers or other stakeholders in urban quality improvement. However, before leveraging GIS in a new assessment framework, livability as a concept needs a more precise definition, particularly since its factors and their transferable assessment have not been sufficiently investigated to date.
Accordingly, instead of static, separate factors, the spatio-temporal patterns of urban life should be grasped in context to understand most of the phenomena. This can be performed by applying an integrated approach in an assessment framework where not only are simple values measured, but the connections between the factors and spatio-temporal aspects are also considered. For instance, encounters, optional and necessary outdoor activities and their spatio-temporal characteristics, or accessibility to specific functions (e.g., shopping, leisure, meeting) can provide indirect information on urban environmental quality, and therefore have an influence on livability. However, simple factors and metrics such as the number of shops or parks (without considering how they can actually be accessed) are not able to represent these phenomena in relation to each other, and thereby actual information on the person–environment relationship is lacking [21
]. The difference might be not so significant in the input data sets or the analysis methods, but the overall interpretation for livability is highly relevant.
Although our sample sizes did not facilitate reliable city-specific results, we could still identify typical characteristics of perceived livability in developing and developed areas. This is also relevant, because urban processes influencing the livability of a city often differ in developing and developed areas. For example, due to rapid urbanization, many developing cities struggle with informal settlements [4
] or lacking access to other basic needs, such as clean drinking water, as is also reflected by several SDGs and NUA goals addressing the issues of developing areas [7
]. Differences between developing and developed countries in our survey were marked by the expectations that citizens based the satisfaction of their needs on the available urban services and facilities. While in developing countries people may often aim to have access to basic services such as clean water or a continuous electricity supply, in developed countries, practically almost all citizens are satisfied with the available basic services and they aim rather for higher quality of life, for instance having access to leisure facilities or urban greenery. This was also reflected by the overall satisfaction with living in a given city, where residents of cities from developing areas generally tended to have a lower satisfaction with urban life; however, in terms of the importance of the given factors asked about in the questionnaire, there were smaller gaps.
In the case of mobility, there were differences in the typical transportation modes between developing and developed areas, especially in motivations for car usage (Figure 8
). It was clearly shown that in developing areas, the main reason why one might use a car on a daily basis was thanks to a lack of competitive alternatives, such as safe cycling infrastructure or accessible public transportation. Further details of car usage and the distribution of responses regarding other mobility-related factors can be found in Reference [53
The livability framework described in the previous sections served as a basis for performing the actual livability assessment (Figure 9
). The assessment has two possible use cases. It either considers all the livability-related elements in the form of a general assessment by analyzing all of the factors for the whole city (or a given area), or it can be used as a preparatory diagnostic step for specific projects on urban quality improvement. In the latter case, depending on the goal of such a project, a subset of the relevant assessment factors should be selected.
Our results can also be utilized and interpreted for implementation of the NUA and SDGs in various ways:
Detailed investigation using all factors: This approach provided a thorough analysis, where individual perceptions and expectations were given a high relevance. The limitation of the method is clearly how time- and resource-consuming it is to interview enough people. Therefore, this approach might be optimal for smaller areas, and for investigating the expectations of different socioeconomic groups. However, by adding spatial aspects based on the approximate addresses of the people, the GIS analysis can reveal further issues and differences at finer spatial scales as well. If the investigation has a more specific purpose than a “general diagnosis”, some thematic factor groups may be omitted. For example, in a transportation-related project, community aspects might have a lower relevance.
Using the key livability parameters: By using the identified subset of livability parameters, researchers and planners can still investigate the quality of an area thoroughly, but in a slightly less resource-consuming way. This type of assessment can still provide details about the different aspects of livability, along with the calculated probability values that can be utilized as weights in the end. Again, the responses of the people can be localized at finer scales within the city; it is therefore possible to locate areas with given problems based on the responses. For example, if in one area people are less likely to commute by bike, or have a lower level of perceived safety, such information may provide relevant input and starting points for further planning steps.
Using probability values as weights: Researchers and planners might decide to only use the calculated probability values as weights for some or all the listed parameters to evaluate the overall performance of an area in terms of livability. In this case, spatial aspects might have a lower relevance, depending on the purpose of the analysis.
Modeling: As our validation example illustrated, if a comprehensive analysis is not required, using only three parameters can also represent livability in an area very well. In our case, out of these three parameters, only one had personal relevance, which can again limit the direct involvement of residents in the analysis process. When asking a large enough number of people only about their overall perceptions of the built environment, combined with the spatial analysis of the other two parameters, it was still possible in our study to get a good approximation of the level of livability.
Overall, researchers, decision-makers, urban planners, and other stakeholders can profit from considering spatial and temporal characteristics of livability and various urban subsystems using GIS. Especially valuable is the ability to identify and “diagnose” areas where residents have lower satisfaction. This “diagnosis” of a city, combined with different visualization techniques, can help raise awareness about the residents’ needs and expectations, and aid in the achievement of SDGs and NUA goals. By using this assessment workflow in a local context, planners would be able to assess and address local circumstances in terms of livability and the satisfaction of the residents. For example, in the case of mobility, by considering the person–environment relationship, issues with commuting or specific problems with the quality and accessibility of public transportation can be identified and addressed within a systematic livability framework. Thus, the concept of livability can guide a whole-systems approach to the person–environment relationship, integrating spatio-temporal aspects as well as highly variable local circumstances.
Beyond utilizing the whole-systems approach of livability assessment in planning, these results can also be directly connected to specific SDGs and NUA goals. SDG 11 targets emphasize the role of adequate housing conditions (11.1), safe and affordable public transport (11.2), good air quality (11.6), and safe and inclusive public (green) spaces (11.7), and the relevance of these aspects in livability was also justified by our results (see also Reference [53
]). However, urban form and active mobility aspects (such as walking and cycling) were identified as even more important in terms of livability, but they are not addressed directly as targets in the SDGs. Active mobility can serve as an important way to reduce greenhouse gas emission (emphasized in the NUA); however, this is, again, more like an ultimate goal per se than a way to achieve such goals. Providing attractive conditions and environments for walking and cycling (as considered in our assessment framework) can have a widespread impact on people’s perception and satisfaction, and also overall as an overspill effect on sustainability. Last, access to basic needs was also acknowledged as an essential characteristic of livable cities as part of both the SDGs and NUA [53
], and the spatio-temporal analysis approach can help to investigate this access in cities, contributing to the long-term achievement of the respective goals.
Once again it must be noted that livability assessments, like many other concepts and frameworks, have their limitations. These limitations might be deeply rooted in the concept itself, such as the high level of subjectivity in articulating human needs and perception, or the complexity arising from the several interrelated parameters. At the same time, this subjectivity should never be neglected or underrepresented in the process. This means that subjective parameters cannot be tested without surveying at least some residents. Other—less inherent—limitations tend to be more related to the data used for the assessment. For example, it matters whether they are available at the right spatial scale or for the right temporal extent, not to mention their representativeness regarding the investigated phenomena. As our GIS analysis illustrated, the results of an assessment usually have to be aggregated in spatial units. Like every aggregation, such a step may entail some information loss. However, aggregation at the right scale increases the range of assessment options, as data at very fine spatial scales are rarely available. In this sense, we suggest that future research related to our investigation could apply multi-level regression modeling in order to identify variations of livability perception through diverse zones within the city. The advantage of this modeling is that regression analysis considers both spatial (census tracts, neighborhoods) and human (interviewees) aspects.
As a follow-up of this work, it could be further investigated whether there is a general, intersubjective measure of “good quality” for those parameters with inherent spatial aspects. This includes most of the introduced variables, except for the community-related ones. A deeper investigation of the street network density categories and their influence on livability could also bring new insights into livability assessment and improvement. Another promising field of future research is the integration of a sense of place into the GIS-based modeling of livability. Due to its perceptional and spatial characteristics, livability may be interpreted through a function-based model of place, where place is seen “as a system of interrelated components” [56
] (p. 16). Moreover, components of livability could be modeled considering the integration of concepts of urban quality of life and geospatial information [23
Because of its complexity, livability assessment requires a whole-systems approach, considering both its key elements and their evaluation. First, we identified several such key elements, and then designed a survey to ascertain city-dwellers’ preferences for the individual factors. As a follow-up, we implemented regression analysis and relational-statistical learning to investigate the role of individual factors in the overall livability of a place. We found that urban form and particular mobility-related factors had the strongest connection with experiencing high urban livability. However, the development of an area, the salary in terms of satisfying basic needs, and general housing conditions also strongly influenced this overall satisfaction with living in a city. As a final step, we illustrated the potential of GIS analysis by modeling livability based on two specific urban form-related factors, considering street furniture and trees.
We can conclude that the residential preferences towards the various elements of livability are similar in developing and developed areas; however, the overall satisfaction with urban life already shows significant differences, as dwellers in developing areas often lack access to basic services. Further city-specific results were beyond the scope of this research article, as we were focusing on transferable assessment techniques. However, in the case of planning actions, these local characteristics are essential to consider in order to improve livability more efficiently or to achieve SDGs and NUA goals.
Finally, we discussed possible methods by which to utilize the livability assessment framework in planning, in particular in implementing both SDGs and NUA goals. Although this approach has evident limitations, we concluded that it could be beneficial in urban planning to “diagnose” a city by measuring livability characteristics before and after performing actual planning actions, with the assessment of livability thereby providing better guidance in the process of urban quality improvement.