Social Cost-Benefit Analysis of Bottom-Up Spatial Planning in Shrinking Cities: A Case Study in The Netherlands

In current research, the social return to citizens initiatives is important but often underevaluated. Within this work, we collected the information that has emerged from measuring the social value of regenerative projects in shrinking cities. We used a case study of the regenerative project Gebrookerbos, a socio-spatial regeneration project in the shrinking city of Heerlen, the Netherlands. To assess the project’s monetary and immaterial aspects, a social cost–benefit analysis (SCBA) was used to understand the complexities of the costs and benefits associated with citizens in regeneration projects in a shrinking area. Drawing from the literature on urban shrinkage, citizen involvement, and social cost–benefit analyses, a theoretical framework was proposed. The case study included primary (i.e., interviews) and secondary (i.e., document analysis) data to identify the social value of the Gebrookerbos project, with results suggesting that the project has been meaningful to diverse stakeholders. Based on experiences with the SCBA of Gebrookerbos, one finding was the complexity of measuring citizens’ initiatives in terms of social return due to their process, organisation, and goals, in combination with the dynamics of shrinking cities. We discuss why research on social return to citizens’ initiatives is important and with this study we draw attention to the tendencies, opportunities, and future potential of citizens’ initiatives, which contribute to vacant open spaces and quality of life in shrinking cities.


Introduction
In recent years, there has been an increasing trend toward citizens' initiatives that contribute to the regeneration of shrinking areas, or places declining in population and economic activity [1][2][3][4]. Involving citizens in urban transformations produces benefits independently of the dynamic of shrinking or growth. Nevertheless, in the case of shrinking cities, the involvement of citizens is a vital part of the regeneration strategy. In this respect, Dutch citizens are taking on leadership roles to contribute to the quality of life in their immediate surroundings, and local governments are encouraging such development, supporting citizens' initiatives [4][5][6]. Including citizens in the regeneration of shrinking areas has attracted significant academic attention [7][8][9][10][11][12]. For example, differences are evident regarding perceptions of active civic action among citizens in shrinking areas [12], and regarding capacities to be involved in the regenerating of vacant and open spaces [13]. Many benefits are associated with citizen initiatives regarding regeneration of shrinking areas: these derive from citizens themselves [14], as citizens become involved with what is important to them [9,15,16]. The result is stronger, a more sustainable connections created 2 of 13 between citiziens within these areas. [17][18][19]. Additionally, involving citizens reduces costs for local authorities in terms of providing services and maintenance [4]. Attention to and relevance of citizens' initiatives for the regeneration of shrinking cities raises the question of how to measure value of citizens' initiatives and the role other actors play in them.
Governments and other stakeholders seek to evaluate the value that citizens' initiatives add among stakeholders in shrinking area [9,20], using various instruments to evaluate both process and results of the participation of citizens. Examples include surveys, interviews, neighbourhood meetings, and reports and accounts from initiators themselves [21,22]. It is common for financial value, such as money invested, and social value, such as immaterial value (e.g., relationships, networks, knowledge, and skills), which cannot be expressed monetarily, to be investigated. However, assessing the combination of both financial value and social value remains rare.
We discuss why research on social returns associated with citizens' initiatives is important, including what lessons have emerged from measuring social value of regenerative projects in shrinking cities, considering financial investments and gains. We use social cost-benefit analysis (SCBA) to measure monetary and immaterial results from bottom-up regeneration projects in a case study of Gebrookerbos, a socio-spatial regeneration project in the shrinking city of Heerlen, the Netherlands. We thus demonstrate the social value of quality of life in shrinking cities in the Netherlands by addressing what can be learned using SCBA to assess social returns from regeneration projects in shrinking cities. We use SCBA to understand the complexity and value of citizens involvement in bottom-up regeneration projects including the costs and benefits of these type of regenerative projects in a shrinking area. Drawing from literature on urban shrinkage, citizen involvement, and social cost-benefit analyses, this paper constructs a theoretical framework (Section 2). We then discuss the case study and the methodological approach used during this study (Section 3). We report results, discuss them (Section 4), and offer conclusions (Section 5).

Regeneration of Shrinking Cities
Shrinking cities are commonly small-and medium-sized urban areas, characterized by decreasing numbers of residents, a declining economic base, and social problems [23,24]. Such cities are prevalent throughout Europe, and they are predicted to continue growing in the near future [24][25][26]. In such cities, liveability challenges, including problems with physical infrastructures, social problems, and economic decline, are also common [27], since shrinkage affects economies, demography, geography, and a city's social and physical aspects [28]. The term shrinking suggests various negative consequences to an area's economic and social development [25], including, for example, oversized infrastructures, stressed finances, and housing and land vacancies. These challenges evoke questions for policymakers regarding how to deal with the changes and challenges that shrinkage poses. For this reason, many shrinking cities invest in diverse regeneration projects that focus on infrastructure, provision of services, and keeping liveability to some standard. To enhance regeneration, citizen involvement is desirable [5,12].

Citizen Involvement: Advantages and Challenges
In the Netherlands, citizens' initiatives play a role in developing solutions for disappearing services and declining neighbourhoods in the regeneration of shrinking areas [4]. In this paper we define regeneration as an approach to city planning, including the process and products developed, to tackle problems raised by shrinking in order to improve physical, economic and social environment. Citizen involvement in regeneration projects offers advantages, such as allowing residents to decide what happens in their city and engaging residents in governance [29]. Some authors argue that citizen involvement can facilitate sustainability of regeneration projects, connect better with citizens' lives and priorities, and reduce costs associated with regeneration [12,30]. Moreover, involving citizens in regeneration projects can result in positive changes of their perception of the Sustainability 2022, 14, 6920 3 of 13 city and stronger sense of belonging [3,31]. Combined with a climate of austerity and structural budget cuts in shrinking cities, regeneration of shrinking cities has led local governments to search for solutions in which residents take on greater responsibilities to deal with local liveability [12]. It can be argued this is a desirable development as not involving the citizens in regeneration can result, for example, in resistance to regeneration and exclusive homogenisation of urban environment [32]. Nevertheless, many challenges are associated with the intention of involving citizens in regeneration. Ročak et al. [33] found that low trust among stakeholders results in reduced citizen empowerment and participation during formal activities. Ubels [4] argues that involvement of citizens in the governance of shrinking areas can be uncertain if it depends on enthusiasm from individual civil servants and governors and external funding. Moreover, community's resourcefulness regarding social and cultural capital is associated with the will and capacity of citizens to be involved in the governance (idem). In other words: more cultural and social capital implies more involvement. However, shrinking cities often show lower levels of these capitals [12].
The idea that involving citizens reduces municipal costs associated with public-space maintenance is commonly inaccurate as the regeneration projects that involve citizens come with costs [4], creating a paradox for governments that want to shift part of the responsibility to residents. Facilitating this shift implies investing money and other resources, and regarding these costs, it is questionable whether individual citizens can manage general interests [4], that is, the complex dynamics of interactions among various stakeholders, drawbacks associated with a project's high costs, and insufficient representation [4,12].
Involvement of citizens and effects on the success of a regeneration project depend on the objectives of the parties involved. Van Dam et al. [34] argue that results of citizens' initiatives depend on which parties are involved and the expectations they have of initiatives. One question, then, is whether success and citizen involvement should be measured in terms of costs and benefits. According to Andersson et al. [35], applying cost-benefit analysis ensures consistency during public decision-making, and might reveal public decision-making processes and make political processes transparent. It might also thus reveal costs and benefits associated with citizens' initiatives during regeneration projects in shrinking cities. In terms of measuring such projects, it is important to consider initiatives' dynamic processes because effects are not always intended, and initiatives do not always go as expected, making unexpected effects difficult to predict [7,34].

Social Cost-Benefit Analysis (SCBA)
The SCBA identifies social return on investment as receiving increasing attention from governments to measure interventions in the social domain and important for the justification of public expenditures [36,37]. Larsen and De Boer [38] argue that social returns refer to the added value of a project or intervention for society; it addresses the question of how the costs of a project relate to social benefits, which represent the reason organizations engage in them. SCBA makes investments in time, resources, and networks visible [35,36], which is relevant to municipalities and other stakeholders who support initiatives, and to potential initiators who want to start such an initiative.
Affecting as many members of society as possible is part of the study of social returns, and it is thus not only about material, but immaterial results, the value of which cannot be expressed monetarily [36][37][38]. Discussing value and price, Ackerman and Heinzerling [39] argue that using market principles for public policies overlooks the possibility that people have disparate preferences when they take on various roles in society. Immaterial results include time saving, networks, activities, knowledge, and in-kind investments that also express the value, in this case, of citizens' initiatives [34]. Other components important to valuing initiatives include the legitimacy of an initiative, the stakeholders to whom profits (i.e., returns) will go, and the ownership of the initiative [40]. Considering these components, returns are not limited to financial benefits, and thus during analyses of initiatives, a balance should exist between tangible (i.e., material) and intangible (i.e., immaterial) costs and benefits [40]. SCBA, therefore, contributes to assessment of citizens' initiatives during regeneration of shrinking cities, but assessing bottom-up regeneration projects in that context is rare.

Gebrookerbos Project Description
Gebrookerbos was a regeneration project that was conducted from 2016 to 2020 in Heerlen North, the Netherlands, with the purpose of contributing to quality of life and bottom-up development using citizens' initiatives to deal with demographic declines, associated vacancies, and demolition of buildings that created vacant and open spaces in the area. Several stakeholders, including policymakers, civil servants, boundary workers, and residents, cooperated to give new meaning to these vacant areas through networking. The project allowed Gebrookerbos citizens to claim, both literally and figuratively, space to deal with area development, and it supported civil initiatives by creating a role of the boundary worker (in the context of this project, we referred to this as Brooker), a professional who mediates various stakeholders and supports them during ideation, realization, and sustainability of civil initiatives. Citizens had the ability to use an open vacant space to initiate a regenerative initiative which improved the quality of live in these spaces and the surrounding neighbourhoods, street or living area. A team of municipality officials (i.e., account managers) also offered guidance and support regarding procedural issues. Various actors were involved in the project, and interventions were used and activities carried out, such as conferences, theme meetings, courses, and social media, to assist initiatives. The Gebrookerbos Fund allowed citizens to apply for financial support, with initiatives with the aim to conduct recreation, urban agriculture, and natural encounter activities in open vacant spaces. Seventy-two initiatives were started, and 18 remain active, including, for example, horse stables and town gardens. See Figure 1 for a map of shrinking city Heerlen and a map of Heerlen-North (Gebrookerbos project area). also express the value, in this case, of citizens' initiatives [34]. Other components important to valuing initiatives include the legitimacy of an initiative, the stakeholders to whom profits (i.e., returns) will go, and the ownership of the initiative [40]. Considering these components, returns are not limited to financial benefits, and thus during analyses of initiatives, a balance should exist between tangible (i.e., material) and intangible (i.e., immaterial) costs and benefits [40]. SCBA, therefore, contributes to assessment of citizens' initiatives during regeneration of shrinking cities, but assessing bottom-up regeneration projects in that context is rare.

Gebrookerbos Project Description
Gebrookerbos was a regeneration project that was conducted from 2016 to 2020 in Heerlen North, the Netherlands, with the purpose of contributing to quality of life and bottom-up development using citizens' initiatives to deal with demographic declines, associated vacancies, and demolition of buildings that created vacant and open spaces in the area. Several stakeholders, including policymakers, civil servants, boundary workers, and residents, cooperated to give new meaning to these vacant areas through networking. The project allowed Gebrookerbos citizens to claim, both literally and figuratively, space to deal with area development, and it supported civil initiatives by creating a role of the boundary worker (in the context of this project, we referred to this as Brooker), a professional who mediates various stakeholders and supports them during ideation, realization, and sustainability of civil initiatives. Citizens had the ability to use an open vacant space to initiate a regenerative initiative which improved the quality of live in these spaces and the surrounding neighbourhoods, street or living area. A team of municipality officials (i.e., account managers) also offered guidance and support regarding procedural issues. Various actors were involved in the project, and interventions were used and activities carried out, such as conferences, theme meetings, courses, and social media, to assist initiatives. The Gebrookerbos Fund allowed citizens to apply for financial support, with initiatives with the aim to conduct recreation, urban agriculture, and natural encounter activities in open vacant spaces. Seventy-two initiatives were started, and 18 remain active, including, for example, horse stables and town gardens. See Figure 1 for a map of shrinking city Heerlen and a map of Heerlen-North (Gebrookerbos project area).

Gebrookerbos as a Regeneration Project: A Bottom-Up Approach
In the Netherlands, involving citizens in the regeneration of public spaces is observable, with local governments encouraging citizens to take on more initiatives to increase the quality of life in their immediate area, such as open public spaces. Citizens simultaneously have heterogeneous demands and perceptions about how the liveability of their neighbourhoods should be increased [41]. Due to such trends, the roles and tasks of governments and citizens in society are changing, referred to as development from government to governance [42,43].
Bottom-up governance [44], in which residents and entrepreneurs are allowed to initiate activities on vacant and open spaces, is one of the most important features of the Gebrookerbos project. The approach differs from traditional top-down governance, in which the government works, sometimes with market parties, to create long-term master plans as solutions to vacant and open spaces, where the cooperation with citizens in the decision-making and implementation process is limited. Market parties then implement these plans, and citizens are involved only during final phases and have limited say in the quality of the plans and the ability to be politically represented in the process. With regard to regional planning, Pissourios [45] demonstrated that both approaches have advantages but also weaknesses that make them suitable for application in certain planning scales and concludes that bottom-up approaches are more suitable for local urban planning.
The Gebrookerbos project involved a shift to the discourse of local government, from leading governance to self-governance, in which citizens were central and contributed their own substance to vacant and open spaces, with support from the government [13]. Proportional communication among the government, citizens, and market appears to be an important factor in such an approach. Healey [46] argues that a consensus approach is possible in regenerating areas where various actors share and take responsibility. Cooperation among government, citizens, and the market was, therefore, important to the Gebrookerbos project, involving various social systems that interacted [45]. Luhmann [47] suggests, however, the exchange of information is not an open process, because differing definitions and concepts of the system (i.e., the municipal apparatus) are used to interpret information that comes from outside the system (i.e., citizens). One strength of Gebrookerbos was that achieving consensus, as much as possible, between disparate parties was emphasized.

Method: Indicative SCBA Gebrookerbos
In order to research the regenerative project Gebrookerbos, an embedded singlecase design was chosen to examine the case Gebrookerbos and to analyse the various components, such as actors, initiatives, processes and procedures [48]. The analysis of these components was important in determining the (social) effects, which ultimately provided insight into the social return on investment of the project Gebrookerbos. During the study of Gebrookerbos, social returns were mapped using SCBA, an instrument that measures the monetary and immaterial results of an intervention or project systematically. During this case study, we used indicative SCBA, which recognizes that, due to a lack of information, not everything can be quantified, and therefore an indication of costs and benefits was used. Indicative SCBAs are based on substantiated assumptions or expectations from experts and is an appropriate instrument in the early stages of policy development [49]. Gebrookerbos was an experimental project conducted in order to determine whether bottom-up spatial planning (giving citizens the opportunity to regenerate open and vacant spaces) should be implemented as a policy option. Indicative SCBA was conducted by assessing Gebrookerbos both with and without the project (alternative). The benefits and costs of Gebrookerbos were expressed monetarily which applies to things that cannot be expressed directly in money. Hypothetically, if benefits exceed costs, a project results in an increase in experienced quality of life [36,38]. Immaterial results, for example time savings, networks and developed knowledge, of Gebrookerbos were merged with financial overviews of cases of regeneration projects.
Gebrookerbos as a project alternative SCBA follows several steps. First it identifies a problem (i.e., what will happen without the project), then it identifies project alternatives and indicators to be measured. Heerlen's government was searching for a solution to improve the physical and social infrastructure of the city to redefine its development. As no one had come forward (e.g., market parties) to propose how the city could utilise vacant and open spaces, the area became run-down, creating a nuisance for residents and feelings of insecurity. The Gebrookerbos regeneration project applied a new approach to the problem: a project alternative that gave residents the opportunity to contribute to bottom-up development, which focused on improving the quality of life in the city and to enhance the opportunity of citizens to develop activities and open spaces and contribute to the feeling of ownership for their neighbourhoods. The Sustainability 2022, 14, 6920 6 of 13 municipality wanted to gain insights into the extent to which the approach contributed to the quality of life and ownership of immediate surroundings by the citizens.
Implementing project-wide research Project-wide research required an analysis of costs related to Gebrookerbos (i.e., boundary worker and account manager, and funds allocated from Gebrookerbos Fund) and benefits realized from the project. Using several indicators (as shown in Figure 2), to determine which characteristics a citizen's initiative must have in order for the project were to be socially profitable in the short-and long-term for those involved directly and among stakeholders in the area, such as the increase in safety, decreases in nuisances and degeneration, the extent of social activities, daytime activities, and voluntary work, and maintenance costs of the open space. These indicators were as much as possible expressed in euros. Intangible indicators were also included, such as the sense of ownership and the relationship between government, initiators, and partnerships that formed throughout the initiative. parties) to propose how the city could utilise vacant and open spaces, the area became run-down, creating a nuisance for residents and feelings of insecurity. The Gebrookerbos regeneration project applied a new approach to the problem: a project alternative that gave residents the opportunity to contribute to bottom-up development, which focused on improving the quality of life in the city and to enhance the opportunity of citizens to develop activities and open spaces and contribute to the feeling of ownership for their neighbourhoods. The municipality wanted to gain insights into the extent to which the approach contributed to the quality of life and ownership of immediate surroundings by the citizens.
Implementing project-wide research Project-wide research required an analysis of costs related to Gebrookerbos (i.e., boundary worker and account manager, and funds allocated from Gebrookerbos Fund) and benefits realized from the project. Using several indicators (as shown in Figure 2), to determine which characteristics a citizen's initiative must have in order for the project were to be socially profitable in the short-and long-term for those involved directly and among stakeholders in the area, such as the increase in safety, decreases in nuisances and degeneration, the extent of social activities, daytime activities, and voluntary work, and maintenance costs of the open space. These indicators were as much as possible expressed in euros. Intangible indicators were also included, such as the sense of ownership and the relationship between government, initiators, and partnerships that formed throughout the initiative.  A distinction was made between implementation, of which there were 18 bottom-up initiatives conducted from 2016 to 2019, and potential costs and benefits, in which all initiatives (i.e., 72) were included during the analysis. These bottom-up initiatives were all initiated by citizens living in the surrounding area of Heerlen and who were given the opportunity to develop activities and the open vacant space with the theme of recreation, urban-agriculture and natural encounters. The first step of indicative SCBA was to investigate the 72 citizens' initiatives. These initiatives were divided into three categories: the idea phase or start-up, realised (i.e., fully active) and temporarily discontinued. A more detailed analysis was conducted on the 18 citizens' initiatives, which were categorized as realised, making it possible to examine two scenarios: real and potential costs and benefits. Real costs and benefits (i.e., Scenario R) included an analysis of the 18 realized initiatives, and potential costs (i.e., Scenario P) was based on the 72 initiatives: the realized initiatives (18), those still under development, and those temporarily stopped. A selection was made of three initiatives for SCBA that were illustrative of social returns of the Gebrookerbos regeneration project: the three themes (recreation, urban-agriculture and natural encounters) and part of the 18 realized initiatives in order to investigate the social costs and benefits during the research project.
Three selected initiatives During the indicative SCBA, the three chosen and representative realised citizens' initiatives were analysed over the period 2016-2019, with results from the initiatives (i.e., cost-benefit, financial, and in-kind), interviews with initiators, and indicative costs and revenues were assessed. Cases were selected on behalf of the three themes of the project Gebrookerbos: (1) urban agriculture, which refers to bottom-up citizens initiatives, which were conducted to increase agricultural activities in the city of Heerlen to cultivate found in or around urban areas; (2) natural encounters, which are the citizens' initiatives creating natural open spaces, such as urban gardens, parks and forests, with the aim to increase natural open spaces in the urban area; (3) recreation, including the citizens' initiatives that include specific recreational activities in open spaces such as sport, art, historical and leisure activities.
The three selected citizens initiatives for the analysis included the Urban Agriculture Foundation Heerlen, Schurenbergerpark, and the Hors Paradise Gebrook. Analysis of these three initiatives offered insights into investments made by initiators and revenues acquired through citizens' initiatives. Horse Paradise Gebrook is a recreational citizen's initiative in an open area, set up with horses for young people with psychosocial problems and school pupils who have temporarily dropped out of school and need some time to readjust. This initiative gave meaning to vulnerable residents who need an informal daytime occupation by taking care of horses. Agriculture Foundation Heerlen is an urban agriculture initiative which includes the growing of fruit and vegetables in an open space for and by residents, with or without vulnerabilities (e.g., minors), contributing to various social activities and events at neighbourhood, district, and city levels. Schurenbergerpark is a natural meeting place created in an open space that can host, for example, a tree-planting day, during which residents could adopt a tree and be responsible for its care and maintenance. Indicators ( Figure 3) were developed to measure indicative costs and gains realized from the initiative, with in-kind benefits and gains included during analysis. ters) and part of the 18 realized initiatives in order to investigate the social costs and ben-efits during the research project.
Three selected initiatives During the indicative SCBA, the three chosen and representative realised citizens' initiatives were analysed over the period 2016-2019, with results from the initiatives (i.e., cost-benefit, financial, and in-kind), interviews with initiators, and indicative costs and revenues were assessed. Cases were selected on behalf of the three themes of the project Gebrookerbos: (1) urban agriculture, which refers to bottom-up citizens initiatives, which were conducted to increase agricultural activities in the city of Heerlen to cultivate found in or around urban areas; (2) natural encounters, which are the citizens' initiatives creating natural open spaces, such as urban gardens, parks and forests, with the aim to increase natural open spaces in the urban area; (3) recreation, including the citizens' initiatives that include specific recreational activities in open spaces such as sport, art, historical and leisure activities.
The three selected citizens initiatives for the analysis included the Urban Agriculture Foundation Heerlen, Schurenbergerpark, and the Hors Paradise Gebrook. Analysis of these three initiatives offered insights into investments made by initiators and revenues acquired through citizens' initiatives. Horse Paradise Gebrook is a recreational citizen's initiative in an open area, set up with horses for young people with psychosocial problems and school pupils who have temporarily dropped out of school and need some time to readjust. This initiative gave meaning to vulnerable residents who need an informal daytime occupation by taking care of horses. Agriculture Foundation Heerlen is an urban agriculture initiative which includes the growing of fruit and vegetables in an open space for and by residents, with or without vulnerabilities (e.g., minors), contributing to various social activities and events at neighbourhood, district, and city levels. Schurenbergerpark is a natural meeting place created in an open space that can host, for example, a treeplanting day, during which residents could adopt a tree and be responsible for its care and maintenance. Indicators ( Figure 3) were developed to measure indicative costs and gains realized from the initiative, with in-kind benefits and gains included during analysis.

Documentation analysis
Cost and benefits analysis are mainly based on analytical empirical evaluations of units' costs of interventions already conducted in similar interventions. However, due to the experimental and unique characteristics of this project, the data that could be used based on a project similar to Gebrookerbos is not available. Because of this reason, various

Documentation analysis
Cost and benefits analysis are mainly based on analytical empirical evaluations of units' costs of interventions already conducted in similar interventions. However, due to the experimental and unique characteristics of this project, the data that could be used based on a project similar to Gebrookerbos is not available. Because of this reason, various documents were consulted to gain insights into the financial effects of the Gebrookerbos project, such as time sheets, budgets, and lists with tariffs for goods, services and materials from different parties, such as municipality of Heerlen, the Gebrookerbos project supervisory team, citizens initiators and other stakeholders (directly) involved in the Gebrookerbos project, and initiators of the citizen's initiatives that were studied in this research. To determine the costs and the effectiveness of the project, municipality time registration systems were used as much as possible. Initiators compiled overviews that provided insights into investments and resources acquired for the initiative. Extant research on project evaluations of Heerlen's municipality was included as secondary data [50,51]. Analyses of these documents were compared and arranged according to indicators of the implementation of project-wide research. Based on estimates, both real and potential costs and benefits are discussed in the results chapter.
Interviews For this study, semi-interviews were conducted with people involved directly in the Gebrookerbos project, including 4 boundary workers, 6 account managers, and 6 initiators (from the 18 realized initiatives). In-depth empirical data were necessary to collect in order to identify the immaterial costs and benefits from the perspectives of the involved parties of the Gebrookerbos project. Using semi-structed interviews allowed us to explore the experiences during the project and the collaboration with different stakeholders in the neighbourhood and surroundings of the bottom-up initiatives. The interviews varied in duration from 30 and 60 min and were used to gain insights into the social value and immaterial effects of Gebrookerbos. The semi-structured interviews included questions about the social value of the initiative for the citizens in the neighbourhood, if the initiative had a focus on a specific target group, had a specific focus or aim (such as developing skills, networks, knowledge or for the increase in social wellbeing) and what kind of collaborations were realized during and because of the realization of the initiatives. Furthermore, interview questions more specific for the initiators about why specific investments were made by them and which benefits were gained by different stakeholders. Additionally, questions to all respondents were about the impact of the Gebrookerbos project for the development of the investigated initiatives, including the actors, interventions, resources and activities.
The interviews were analysed and results were categorised thematically. Two themes emerged: (1) the significance of the initiative to stakeholders and the immediate living area of citizens; an overview of initiator and stakeholder experiences who, according to interviewees, benefitted from the initiative; and (2) the experience of implementing Gebrookerbos; a review of experiences of boundary workers and account managers, who were contact people for initiators.

Monetary investments greater than monetary gains for the Gebrookerbos project and initiatives
The results suggest that monetary investments exceeded revenues; for two-thirds of initiatives, the costs were greater than the financial incomes or resources obtained. Based on the 18 realised initiatives, the results suggest that real monetary costs and benefits created a negative balance. However, from an analysis of the 72 initiatives, the project created a positive monetary balance. Indicative SCBA shows that monetary benefits were behind costs incurred for the project, and that as soon as all 72 initiatives undergo development comparable to the 18 realized initiatives, the project will yield financial return. Thus, it appears that costs yield a social return as more initiatives are realised.
The three initiatives also received donations in-kind. The initiators of these initiatives state in the interviews that they had a large reach among stakeholders, which included entrepreneurs, institutions, and informal networks who collaborated by reusing and sharing tools, materials, and resources. Such multi-sector collaborations increased the civic capacities of the collaborating organizations [9], and, thus, community engagement appears to address the problem of vacant and open spaces and assists with long-term regeneration [52]. Interviews among initiators suggested that real improvements have been made to the physical quality of the immediate living environment. Respondents reported that the maintenance and removal of waste was important to increase safety and reduce nuisances and vandalism, and, thus, the quality of life in the neighbourhood. The respondents also reported immaterial gains. Nevertheless, vandalism, for example, represented a monetary cost for the municipality, society, and people living in the area; therefore, avoiding these represents a monetary benefit.
Immaterial gains and investments: the difference between involved groups and challenges associated with measuring SCBA Initiators were in close contact with important stakeholders, such as residents and target groups that were uninvolved at municipality, welfare, and neighbourhood organisations. Results show that initiators invested in activities of their initiative for vulnerable groups, such as voluntary work and daytime activities. According to the respondents, this resulted in residents experiencing fewer nuisances and less degradation. Successful citizen involvement is a dynamic process, during which ideas and opinions are exchanged over time through informational feedback loops that vary across communities [53]. That these dynamics and interactions occur among different groups makes them complex to measure, including which benefits affect target groups, what their involvement is in this process, and how they make sense of places [54] and open urban spaces [55]. Initiators reported that cooperation among volunteers, clients, and visitors is challenging in terms of managing these groups and investments made, which makes them complex to assess in terms of costs and benefits for society. Reaching difficult-to-reach groups and ensuring more pleasant experiences in a neighbourhood for residents are difficult to measure, but they represent gains, nonetheless. These experiences show the limitation of this research in terms of the transferability of the analysis elsewhere. However, the results give an important insight into the indicative costs and gains and way of measuring the elements of citizens' initiatives and the approach of bottom-up spatial planning in shrinking cities.
Importance of pre-investments by initiators Indicative SCBA allowed us to assess various assumptions that subsidy providers held regarding social returns on these initiatives; that is, whether they could survive without financial support from a subsidy provider (in this case, primarily municipality) and whether without this financial aid the initiatives could become sustainable. Among the three initiatives analysed in greater detail, for two, investments made by initiators were higher than revenues. Results also showed that initiators invested much financial, in-kind, and time resources at the beginning, before they sought financial support from government organisations. Initiators initially used alternatives to make their initiatives possible (e.g., acquiring in-kind materials, tools, and equipment from nearby stakeholders). According to the interviewees, applying for government subsidies was the last step in gaining financial support for the initiative. In practice, applying for subsidies is difficult. Penninx [56] argues that in addition to the advantages of receiving subsidies, there are also disadvantages; initiatives must meet many requirements, demonstrate a social return, and follow many procedures. Initiators also spend much time completing paperwork and on administration, and occasionally must adapt their initiatives so that they meet requirements. Governments play a role in reducing bureaucratic procedures that demotivate citizens' initiatives [5]. To remove such barriers, Gebrookerbos set up a fund to offer municipal support to citizens' initiatives as easily as possible and without excessive bureaucracy.
The importance of immaterial support Results suggest that when both monetary and immaterial resources and support are lacking, initiatives struggle with sustainability and development [20,57]. The Gebrookerbos Fund was meant to provide financial support, and it could be applied to all citizens' initiatives associated with the project. During the research period, citizens' initiatives requested one-third of the funds. Using insights from these results, and from interviews among initiators, it is clear that citizens' initiatives were not money-driven, but rather required support, advice, communication, and assistance from the Gebrookerbos implementation team (i.e., boundary worker and account managers), and from the municipal organisation itself [20]. Interviewees reported that efforts from boundary workers and account managers to facilitate Gebrookerbos fund were positive. Since few citizens' initiatives applied to the fund, subsidy providers could benefit. To encourage public engagement to address vacant urban land, both formal (i.e., grass-top) and informal (i.e., grassroots) civic processes should be used to enhance communication and provide diverse experiences to participants [9].
Initiatives' potential to become social enterprises The regeneration project suggests that sustainability and development suffer when both material and immaterial support are absent [20,57], such as financial support, voluntary support from citizens and specific competences (knowledge, skills, attitude), social networks and collaborations with other stakeholders A single project or organization cannot solve all public problems and challenges in contemporary society, such as achieving environmental sustainability, reducing poverty, and improving human health and wellbeing [58]. Instead, these problems must be solved through co-production and planning of multiple sectors, including governmental organizations, non-profit organizations, businesses, and community groups [53]. Regarding this co-production, citizens' initiatives can grow into social enterprises that improve social and society innovations [59,60], and thus the quality of life in the immediate environment and among vulnerable groups in shrinking areas. This notion is paramount because during urban regeneration, both in the U.K. and more recently in the Netherlands, social enterprises have emerged that are partly in response to government retrenchment and budget cuts [44,61]. It is therefore important to follow such initiatives to assess whether citizens' initiatives contribute to structural problems regarding the quality of life or as part of the market in shrinking cities, as a result of this transformation.

Conclusions
In this paper, we address returns on the regeneration project, Gebrookerbos, in the shrinking city of Heerlen, the Netherlands. Indicative SCBA of the project suggests that it has been meaningful to diverse stakeholders. Results suggest that citizens' initiatives cannot be compared directly using a project or intervention from an organisation, municipality, or company. Such initiatives are complex from an organisational viewpoint, and they have a history, a theme, a target group, an approach, support, and basis that derive directly from the environment and stakeholders. These differ so much across initiatives that determining generically their social returns is itself complex. Nevertheless, research offers citizens' initiatives a way to characterise them, indicate what investments they have made, and identify what returns they have acquired for themselves, their surroundings, and the stakeholders with which they work. This kind of analysis, as we have shown with the case study Gebrookerbos, cannot be seen as a blueprint for other regeneration projects. However, the use of the elements and indicators which we have used to measure the regeneration project, Gebrookerbos, and bottom-up citizens' initiatives can be very valuable in order to identify the potential of citizens' initiatives to contribute to the quality of live in other shrinking cities.
The three citizens' initiatives added value to their immediate living environments by offering goods, services, and guidance to various target groups, such as residents, young people, and visitors. Although material investments were higher than financial gains were, they demonstrate that involved parties considered immaterial gains to be more important to long-term developments. Initiators' pre-investments were considerable in terms of costs and benefits, suggesting that governmental funds do not always represent the starting point of an initiative, but come later, after formation of a structure. Investing in relationships among civil servants, facilitated by boundary workers and citizens, led to better cooperation, and thus sustainable cooperation could advance. A co-creative government, with citizens working together, therefore represents an essential condition to enable liveability in shrinking cities [62,63].
Based on this study, a recommendation is to conduct SCBA at the micro level to research social returns explicitly at a neighbourhood or street level, or on a target group. Given the results from Gebrookerbos, future research is needed to identify differences among gains, value, costs, and benefits while researching citizens' initiatives in shrinking cities. Assessing projects and citizens' initiatives in terms of social returns remains complex due to the dynamics involved in regeneration projects. Indicative insights are needed regarding investments, both material and immaterial, and benefits across actors. Using indicative SCBA on Gebrookerbos elucidated tendencies for long-term opportunities, and it was beneficial to identifying future gains across stakeholders. The growth potential of citizens' initiatives toward social or community enterprise is high, where they sustain con-