1. Introduction
Urban renewal has been recognized as a major approach to promoting land values and improving the quality of the environment and human life [
1]. Considering the large concentration of the population and the significant proportion of cities, neighborhoods are considered to be at the microscopic level of urban renewal [
2,
3]. Neighborhood renewal, also called neighborhood regeneration, neighborhood redevelopment, or neighborhood rehabilitation, is a derivation from urban renewal that seeks to improve the condition of neighborhoods from sustainable viewpoints through the integration of people- and place-based strategies. It was introduced in developed countries in the 1990s with final goals of ensuring that local communities are willing to live and work in neighborhoods in the present and future [
4].
Various kinds of neighborhoods have been renewed in both developed and developing countries with different focuses, e.g., disadvantaged neighborhoods in France and the Netherlands [
5,
6], poor neighborhoods in America [
7], deprived neighborhoods in Israel [
8], historic areas in Turkey [
9], low-income neighborhoods in Denmark [
10], deteriorated communities in Korea [
2], and neighborhoods after natural hazards in Japan [
11]. Mainly topics are related to urban decline, safety, health, gentrification, or public participation during the renewal process.
Meanwhile, neighborhood renewal in China mainly refers to the physical rehabilitation of old residential neighborhoods, also called old neighborhood renewal (ONR). With the accelerating pace of urbanization in China, a large number of newly built neighborhoods with multiple supporting facilities and comfortable environments have merged to continuously improve the living quality of urban residents [
12]. At the same time, there are still a large number of old neighborhoods built before 2000 in downtown areas of urban China, which are the shortcomings of urban development and are usually uncoordinated with nearby newly built neighborhoods [
13]. Those old neighborhoods are mainly residential neighborhoods, which generally have particular characteristics of a long development history, poor living quality, and dirty environment that cannot even meet people’s normal living needs [
3,
14].
The outcomes of the renewal projects are discussed a lot by conducting performance evaluations. This refers to a systematic process in which an organization intends to accomplish certain goals, plans how to achieve the goal, and assesses whether the organization has accomplished its goal [
15]. The evaluation can help stakeholders to improve their strategies or solutions in order to achieve the most sustainable outcomes [
16,
17]. Some national assessment tools have been developed and have been commonly in use over the years to promote the high performance of neighborhoods in developed countries [
18,
19,
20], e.g., the Leadership in Energy and Environmental Design for Neighborhood Development (LEED-ND, US), the Building Research Establishment Environmental Assessment Method for Communities (BREEAM Communities, UK) and the Comprehensive Assessment System for Building Environmental Efficiency for urban development (CASBEE UD, Japan). However, those methods are structured according to local requirements, in which the objectives, evaluation criteria, and sustainable indexes are verily defined [
20].
As for research, the indicator-based approach has attracted the most attention in the urban context for performance evaluations [
21]. For example, Hemphill et al. (2004) developed an indicator-based approach for urban renewal evaluation with qualitative discussion and quantitative assessment [
22]. Peng et al. (2015) proposed an alternative model for measuring the sustainability of urban regeneration with indicators considering building performance, environmental, social, and economic development [
23]. Riera et al. (2018) developed an indicator system for measuring sustainable neighborhood renewal from six objectives, including ensuring viability, balancing supply, saving energy resources, and upgrading the local environment [
24]. Li et al. (2016) assessed the performance of public involvement for sustainable urban regeneration based on indicators of inclusivity, equality, transparency, and interactivity [
25].
However, most assessment tools worldwide have been focused on the urban scale or the sustainability of the neighborhood, and performance evaluations specifically for neighborhood renewal projects are limited [
21,
26]. The methods used are mainly subjective evaluations with judgements from experts or questionnaires from the public. There is a lack of quantitative evaluation for the performance of neighborhood renewal projects based on actual situation data. Besides, many of the renewal projects are ad hoc projects without long-term planning, and the sustainability of the renewal outcomes remains a question [
13,
27]. Consequently, many renewed neighborhoods are suffering a “return-back” scenario, which means the neighborhoods will return to their poor situation before the regeneration. This fails to meet the initial objective of neighborhood renewal, i.e., to improve, maintain, and upgrade the living environment and life qualities of an entire nation [
17]. Thus, it is vital to evaluate the holistic performance of these projects after the renewal in order to establish long-term guidelines for urban renewal polices.
Moreover, with a lack of related regulations or codes, it is hard to find a general standard that is suitable for evaluating the performance of any neighborhood renewal project. It is relatively easier to evaluate and compare the advantages of different neighborhood renewal projects. The technique for order preference through similarity to an ideal solution (TOPSIS) is a common method used in multiple criteria decision-making (MCDM). It has proven efficient in the evaluation of the relative merits of existing objects for many years [
28,
29]. Thus, considering the gap in existing studies, this paper tries to provide a comprehensive framework for measuring the relative performance of multiple neighborhood renewal projects with the following objectives: (a) to identify the performance indicators assessing the neighborhood renewal projects; (b) to establish a framework for relative performance evaluations of neighborhood renewal projects through the AHP-TOPSIS method; (c) to conduct an empirical analysis by evaluating the performance of ONR projects in Nanjing, China; and (d) to provide recommendations that will help improve the long-term governance of neighborhoods with existing and future neighborhood renewal projects.
5. Conclusions
Performance evaluations for neighborhood renewal projects are necessary and important for decision-making. Existing studies have rarely focused on the assessment of neighborhood renewal projects. Taking the ONR projects in China as an example, this paper developed a systematic framework for the relative performance evaluations of multiple neighborhood renewal projects through a hybrid AHP-TOPSIS method. The evaluation indicators were chosen from social, economic, environmental, and building dimensions. The results showed relatively moderate levels of performance for the sample neighborhood renewal projects, and each neighborhood needs to choose a priority of strategies for its own characteristics in order to pursue sustainable development.
The evaluation results can help to reveal the strength and shortcomings of different neighborhood renewal projects. It also provides a decision matrix for the priority of strategies for specific neighborhoods in order to pursue the sustainability of renewal projects. The ranking of different neighborhood renewal projects can be used as a reference for project rewards or penalties. This will help to regulate the behavior of private units and encourage supervision by residents. Besides, the framework developed in this paper is also suitable for different neighborhoods in other cities or countries. The indicators and decision-making matrix are not fixed and can be altered to match the circumstances in distinct fields when considering particular contexts in applying performance evaluations in practice. Thus, various kinds of neighborhoods after renewal can be assessed and compared under the same framework. This is a supplement to existing urban renewal studies and provides references for sustainable urban/neighborhood renewal.
More extended work can be developed when large-scale sets of data are available and accessible to assess the performances of renewal projects. For example, acoustic emissions, resource consumption, and waste minimization can be considered in environmental performance evaluations when data are available. Moreover, the performance of a neighborhood renewal project may change with time, and performing regular evaluations is suggested for further comparisons in order to promote sustainable development.