SHARING-BASED CO-HOUSING CATEGORIZATION A STRUCTURAL OVERVIEW OF THE TERMS AND CHARACTERISTICS USED IN URBAN CO-HOUSING

benko@urb.bme.hu The European urban areas are growing fast, with many contemporary housing forms. Among these, co-housing forms related to sharing have become a key issue for urban housing development. These housing forms are analysed (their physical and social characteristics or effects) in more and more publi -cations, without a common terminology of this interdisciplinary research field. In our study, based on the overview of existing definitions, characteristics we introduce a comprehensive sharing based categoriza tion that could be valuable for terms and projects, as well. With the note, that the social dimension of sharing methods would not exist without the physical ones, because in co-housing the shared space is the basic criteria. In this paper, we focus on three groups of the social fields of sharing related to housing: the shared creation, the shared tenure, and the shared activities. We conclude the structural approach of our overview unravels new perspectives for the classification of housing forms. Based on our categori - zation and methodology, we recommend the development of a sharing based scalable classification that measures projects consistent and


INTRODUCTION
There has been a growing interest in developing contemporary forms of housing, including urban co-housing with different sharing methods. The early 2000s new wave of collective forms of housing has appeared in many European countries, which causes a wide variety of alternative forms and models, such as Communal housing, Collective living, Cooperative housing, Collective self-help initiatives, etc. 1 With the growth of sharing related housing forms, the number and variety of research and publications is growing rapidly in this topic. Nevertheless, the field of co-housing stays thematically fragmented, with different forms, which spread across disciplines without clarified conceptual background. At the same time, the sharing became a key issue of contemporary urban housing 2 , actors -users, developers, and academics -use notions related to it, but without clear significance. The used terms and definitions are contradictory or just overlapping 3 , and there is no accepted categorization of urban co-housing. Therefore the existing co-housing terms and categorizations are not adequate to clarify the significant differences between projects. The reasons for the lack of categorization are the unclear use of terms and the unstructured, project-dependent analysis of the sharing methods. 4 Our hypothesis state that sharing methods appear in urban co-housing 5 in varied fields and levels. The physical-architectural sharing methods and social aspects (fields of sharing like creation, tenure, and activities) are strongly interrelated and are interdependent. This aims to give a structural overview of the used terms and definitions and introduce the need for a scalable co-housing categorization that displays the fields and levels of the relevant sharing methods.

THE RESEARCH METHODS FOR THE STRUCTURAL OVERVIEW OF TERMS AND LITERATURE
To demonstrate the hypothesis, first we give an overview of the terms of housing, individual housing, co-housing, and co-housing sub-terms based on international literature review. In addition to the written text, the visualization of the relationship between urban housing terms is a result. Second, we focused on co-housing and collected the appropriate definitions of the co-housing sub-terms. The outcome from this section is not a structured collection of co-housing sub-terms but also the presentation of their corresponding sharing methods. Third, these sharing methods are analysed by the literature review of the cohousing characteristics. We distinguish the physical and social dimension of sharing and present the possible levels of social fields of sharing in the determined system. Finally, we shortly summarize the existing user-oriented urban co-housing categorizations to find the appearance of the sharing methods in them. To highlight the sharing characteristics, we visualized the categorization of the terms, based on the main fields of sharing.

THE TERMS OF EUROPEAN URBAN HOUSING
To find the exact terms and definitions in the co-housing topic, we have to clarify the use of housing. Housing is an interdisciplinary topic 6 with a connection to the wide range of social science, health, and environmental disciplines: sociology, geography, law, politics, public health, economics, accountancy, architecture, and planning, engineering, and environmental science. 7 Due to the diversity of the topic housing classification is diverse. 8 In this housing research, our focus is the usage of sharing methods, so we have to distinguish two basic groups: the individual housing and the co-housing. Individual housing reflects the individual or the traditional family composed of relatives. So individual housing could be defined 9 as one building with one dwelling, having its private entrance, mostly inhabited by one person or his/her relatives without any sharing methods with others. 10 We can state that the co-housing is everything else with evidently shared characteristics concerning outdoor or indoor spaces, everyday activities, creation of the building, and tenure, as well. However, in co-housing different people not from the same family live together in one building with one unit, or one building with several units.

CONTRADICTIONS OF THE EXISTING CO-HOUSING TERMS
This part summarizes the co-housing terms in various studies for housing with shared facilities and other shared characteristics and presents their confusing usage. One reason for the differences is the use in more countries and languages with diverse historical and cultural backgrounds. 11 The other reason is the presence of different fields of sharing in different levels in the alternative urban living forms and by terms, they try to differentiate them. 12 In 2010, Vestbro identified the need to find terms that may be used internationally to avoid misunderstandings. 13 The most commonly used terms for "housing with shared facilities and other shared characteristics" are 'co-housing' and 'cohousing'. These words generally appear as synonyms in the housing literature, and this incorrect wording leads to several misunderstandings. Therefore we tried to determine them consistently and at the same time differentiated the various co-housing terms, based on Tummers termi-6 Ruonavaara 2018. 178-192. 7 Smith 2012. 6-7. 8 Henilane 2016 It should be noted, that there are few hybrid solutions between individual housing and co-housing, such as multi-generational family homes or family-owned multi-unit housing, etc. We dispense with them in the term collection, because of their low number and difficulty in categorization.
10 Insee's definitions 11 Vestbro 2000. 165-166. 12 Franck-Ahrentzen 1991. 3-19. 13 Vestbro 2010. 21. nology 14 and Vestbro's definitions 15 completed with own considerations. As a summary of the inaccurate definitions, Vestbro claimed in 2010 that the concept of co-housing does not state exactly what "co" stands for, it could be collaborative, cooperative, collective, or communal. We agree with him, because this housing concept is spreading rapidly as the universal term, so it is logical to see co-housing as the wider concept. Tummers was the first in 2016, who used the two words with different meanings, but she did not define (determine) the exact definitions. She used co-housing for the wider range of housing initiatives and cohousing for the narrower range of housing initiatives fulfilling all certain co-criteria. It is also important to clarify that these two terms are not abbreviations of other expressions with the "co" word-beginning, like collaborative housing, communal housing, cooperative housing, etc.
Consequently, the terms of co-housing and cohousing have to be defined properly (determined punctually) to avoid misunderstandings. We recommend separated definitions for the two terms: a more strict and narrow use of cohousing and a more extensive use for co-housing. The co-housing term is a general expression, several different models can be distinguished under this wider concept. But the cohousing term can only be used when certain criteria are met, these are explained below.

THE STRUCTURED COLLECTION OF CO-HOUSING SUB-TERMS
Based on the previously defined individual and co-housing terms we classify and explain below the sub-terms of co-housing (Fig. 1). The structured collection of subterms started by Tummers' terminology 16 about different types of co-housing. It contains the characteristic sharing methods of the co-housing sub-terms, which are the following: Cohousing, Collaborative housing, Collective housing, Communal housing, Commune, and Cooperative housing. But certain terms are not included in Tummers' terminology, because she drew a boundary according to the level of sharing. This terminology is forward-looking, but not exhaustive, it is not possible to decide clearly why certain terms are included or not. In our research, sharing at all levels is important, so we continue to systematize with all the well-known co-housing sub-terms that start with 'Co'. The additional terms that we introduced are Collective living, Collective self-build housing, Collective self-help housing, Community-led housing, and Condominium. These terms often appear in contemporary housing literature, so we assume to learn about the new aspects of sharing methods.
The collection of main co-housing sub-terms is completed with other terms that appear in the co-housing literature and are often compared with the co-beginning concepts. In these cases, besides the sharing methods, another contemporary characteristic came into the front, like social care, ecological approach, security-based development, etc. 17 Relying on Tummers' classification of collaborative housing 18 we show the definitions of Eco-village, Eco-district, and Intentional community. From her collection, the Eco-habitat and the Squad are omitted, since they overlap with other terms. On the other hand, we add another frequently used term 19 , the Gated Community. The collection has not included forms of living whose definition is clear and does not confuse the literature with other concepts such as dormitory and elderly home, etc.
There is no consensus on academic and everyday usage of cohousing and the collective housing terms. In the case of cohousing, it has been caused by the mixed use with the co-housing term (explained earlier). The confusion around the collective housing term is because of the parallel use of several models for this concept in the academic field. 20 Therefore we start the clarification with the most problematic terms: the cohousing and collective housing. Then we continue with the other sub-terms in alphabetical order, because their appearance in the literature differs in time.
The cohousing concept was coined in 1988 by Charles Durrett and Kathryn McCamant: "Cohousing is a grass-roots movement that grew directly out of people's 17 Stevenson-Baborska-Narozny- Chatterton 2016. 789-803;Fedrowitz-Gailing 2003. 19.25. 18 Tummers 2017. 19 Ruiu 2014. 316-335.;Chiodelli 2015Chiodelli . 2566Chiodelli -2581. 20   dissatisfaction with existing housing choices. Cohousing communities are unique in their extensive common facilities and more importantly, in that they are organized, planned, and managed by residents themselves." 21 The UK cohousing network defines cohousing as "Cohousing communities are intentional communities, created and run by their residents. Each household has a self-contained, private home as well as a shared community space. Residents come together to manage their community, share activities, and regularly eat together." 22 The Cohousing Association of the United States definition is stated as: "Cohousing is a community intentionally designed with ample common spaces surrounded by private homes. Collaborative spaces typically include a common house with a large kitchen and dining room, laundry, and recreational areas and outdoor walkways, open space, gardens, and parking. Neighbours use these spaces to play together, cook for one another, share tools, and work collaboratively. Common property is managed and maintained by community members, providing even more opportunities for growing relationships." 23 The term cohousing is also used by the Canadian cohousing networks. The latter describes cohousing as "neighbourhoods that combine the autonomy of private dwellings with the advantages of shared resources and community living" 24 . Based on the theoretical approach, case studies analysis 25 , and projects 26 , the Cohousing definition is: Cohousing is a special type of housing with shared characteristics. The shared characteristics must show simultaneously all four following features with a certain strength: sharing of spaces, activities, creation, and tenure. The other problematic term is collective housing. It is not only used to describe multifamily housing in architectural research and practice 27 , but also is a commonly used term in the field of multi-unit housing with special sharing methods. 28 In 1998 Vestbro determined its five different existing models. 29 The first, Swedish model presents "the collective housing unit with a central kitchen and other collectively organized facilities." The second, Danish model began "out of the movement of create stronger sense of community through common activities." Vestbro identifies the third model as "housing areas provided with collective services in order to facil-21 McCamant-Durrett 1988. 15-16. 22 Vestbro 1998. 405-410. itate housework, care and communal participation" and fourth model as "housing for special categories such as elderly people, students, and residents with various types of dysfunction." The fifth model is identified as "the commune, where more than four person, who are not relatives, live and eat together, usually in a large one-family unit." 30 The problem is that these models are widely accepted and cited, but to have five parallel different models for the same term causes misunderstandings. We recommend to use Vestbro's first model, which agrees with Frank and Ahrentzen, so the Collective housing definition is: "Collective housing is a housing that features spaces and facilities for joint use by all residents who also maintain their individual household." 31 There is a consensus in the following definitions of co-housing sub-terms in academic literature and everyday usage, moreover, there are few definitions for one term (the academic described rather the characteristics of the housing forms). We listed full definitions below, to present the relationships among these terms. During the analysis, it became clear that different fields and levels of sharing appear in the used sub-terms that connect them.
Collaborative housing definition: "Collaborative housing is a variety of projects that establish high levels of long-term participative relationships, not only amongst their residents but also between these and a wide range of external stakeholders." 32 Collective living/Co-living definition: "Collective living is a residential structure that accommodates three or more biologically unrelated people" usually in one apartment. 33 Collective self-build housing (Baugemeinschaft): "Housing arranged by groups for their own use; individuals typically commission the construction of a new house from a builder, contractor or package company or, in a modest number of cases, physically build a house for themselves." 34 Collective self-help housing definition: "Bringing empty or derelict properties back into use through renovation by community projects, often involving property acquired by the local authority from the private sector." 35 Communal housing definition: "Communal housing means housing for nonfamily groups with a common kitchen and dining facilities but without medical, psychiatric or other care." 36 Commune definition: "Commune is a group of families or individuals living together and sharing possessions and responsibilities." 37 30  Community-led housing definition: "Community-led housing is a housing project that are focused mostly on affordable homes for the benefit of the local community, either individually or in co-operation with a builder or other local housing provider… The community group will take a long-term formal role in the ownership, stewardship or management of the homes." 38 Condominium definition: "Condominium means, where the owner owns his or her unit in fee simple absolute and shares and undivided interest in the common elements (for example, sidewalks, hallways, pools, clubhouse, storage place) as a tenant in condominium owner." 39 Cooperative housing definition: "Cooperative Housing is an association of people (co-operators), which cooperatively owns and manages apartments and common areas. Individual members own shares in the cooperative and pay rent which entitles them to occupy an apartment as if they were owners and to have equal access to the common areas." 40 Eco-district definition: "Eco-district is an urban development aiming to integrate the objectives of sustainable development and focusing on energy, the environment, and social life." 41 Eco-villages definition: "An ecovillage is an intentional, traditional or urban community that is consciously designed through locally owned participatory processes in all four dimensions of sustainability (social, culture, ecology, and economy) to regenerate social and natural environments." 42 Gated communities: "Gated communities are walled or fenced housing developments, to which public access is restricted, characterized by legal agreements which tie the residents to a common code of conduct and (usually) collective responsibility for management." 43 Intentional community definition: "A planned residential community, designed to have a high degree of social cohesion and teamwork; members typically hold a common social, political, religious, or spiritual vision." 44 Collecting existing definitions related to sub-terms shows the connections and overlaps between various terms, and from the definitions and characteristics the inconsistent vocabulary and wording of the sharing methods clearly appears (Table 1). Although spatial sharing dimensions do not appear in each definition, it turns out that sub-terms have some level of spatial dimensions. The structural review also points to the varied field and level of sharing in co-housing. In the next section, we give a complete overview of the sharing methods based on a literature review.

COLLECTION OF SHARING METHODS, BASED ON COHOUSING CHARACTERISTICS
It can be deducted from the structured collection of co-housing sub-terms that the Commune represents the peak of sharing in housing, thanks to the common ideology. However, the research on Communes sharing methods is problematic, as their literature is less, due to the closed nature of the communes. The next level is represented by cohousing, where all field of sharing except the shared ideology can be found and the cohousing literature is comprehensive. To make understand the sharing concept in housing 45 we focus on cohousing as next to individual housing, the other extremity (after the Commune) of a possible scale.
While there is a common core to characterizations of cohousing, researchers tend to emphasize specific aspects according to their interests. 46 Ruiu has discovered three separated ways in the cohousing literature with a focus on the internal operational model, relations between cohousing and the environment, and internal social dynamics 47 . The literature is mainly produced by architects who are interested in the internal operational model of physical layouts and available common facilities with an outlook to legal forms, decision-making processes, 48 or relations between cohousing and the environment. 49 There is a limited literature on the internal social dynamics in cohousing communities. 50 First in 1988, based on Danish case study analysis McCamant and Durrett identified four common characteristics of cohousing developments: Participatory process (1), Neighbourhood design (2), Common facilities (3), Self-management (4). 51 In 2005, Meltzer completed this definition with two more key characteristics: Absence of hierarchy (5) and Separate incomes (6) 52 In the same year, Chris and Kelly Scotthanson clarified the previous six characteristics: Participatory process (1), Intentional Neighbourhood Design (2), Private homes and common facilities (3), Resident management (4), Non-hierarchical structure (5), No shared incomes (6). Furthermore, for more accurate characterization, they add four specific features: Optimum community size between 12-36 dwelling units (7), Purposeful separation from the car (8), Shared evening meals (9), Varied levels of responsibility for development process (10). 53 Though these six (1-6) characteristics are still widely accepted and referred, 54 not all shared features are included. A number of studies use these, or similar ones to highlight particular aspects, 55 but already Vestbro questions them. 56 According to Chiodelli and Bagione's studies from 2014, it is possible to recognize five characteristics that are necessary and sufficient to define a settlement as cohousing. They left out the characteristics that Vestbro questioned and to the remaining added three new features. These are Communitarian multi-functionality (3), Residents' participation and Self-organization (1) (4), Constitutional and operational rules of a private nature (11), Residents' self-selection (12) and Value characterization (13). 57 In addition to the previous characteristics, in 2020 Giorgi collected secondary features, in order to better describe the cohousing projects. His proposal classifies these features into four groups: Community, Housing, Design, and Context. Community reflects the communitarian spirit within a project: the desire to share, the planned activities, the presence of spaces designed to share. To this group belong Sharing skills, Feeling security, Collaboration, Decision consensus, Shared meals, Focal spaces for community, Common residential spaces, and Common complementary spaces. Housing reflects the residential way of living and the involvement of the residents in the activity of living and housing from the planning to the management of the project. To this group belong Mix of residents, Self-development, Self-construction, Link with production activities, Partial food production, and Privacy. The Design reflects the design methods used by the development process of the project, the approaches toward sustainable features, and the participation of the future inhabitants. To this group belong Sustainable approach, Reuse, Flexibility, and Participatory design. Context reflects the relationship with the physical and social environment, according to the involvement of the community in the life of the neighbourhood. To this group belong Integration, Innovation, Participation, and Identity. 58

SYSTEMIZATION OF SHARING METHODS IN URBAN CO-HOUSING
In the systemization, we structure the fields and levels of sharing methods in urban co-housing. Following Jarvis 59 , Sanguinetti, 60 and Williams 61 , who argue for the understanding of co-housing as having both physical and social dimensions, we also distinguish the fields of sharing according to these dimensions. Based on the literature, there are varied types of sharing in co-housing according to the physical dimension. The quality and quantity of these are defined by the developer or the future inhabitants. The types of the physical dimension of a co-housing are the following: indoor spaces in the building(s), outdoor spaces (on the plot), common facilities, and devices. 62 Their architectural design and measurable qualities are discussed in numerous analytical papers and case studies 63 . Nevertheless, if we concentrate on the social dimension of the co-housing, three fields of social sharing could be determined based on the cohousing characteristics: the shared creation, the shared activities, and the shared tenure.
It is important to recognize that most of the presented terminology does not differentiate the physical and the social dimension and that is why the use of terms is confusing. To better understand and differentiate co-housing sub-terms, three components of the social dimension are essential, besides the physical dimension (Table 2). 58 Giorgi 2020. 111-114. 59 Jarvis 2015. 93-105. 60 Sanguinetti 2014. 86-96. 61 Williams 2005a. 195-227. 62 Jarvis 2011   The creation could be independent of further users who simply purchase the final housing product, or future residents can share steps from the beginning of the creation process. Varying levels of shared responsibility can be observed for the co-housing development process 64 . Future inhabitants can take part in the idea formulation 65 (Common idea formulation), have the control of design decisions (Participatory design process), have maintained complete control -acting as their developer 66 (Community self-development). Inhabitants can also participate in some part of the construction work, it is typical for remodelling a building or for minor finishing construction works 67 (Community self-construction). In European cities, it is also possible to find networks and use other groups' experiences on shared development (Joining to collaborative housing movement). 68 The activities between residents in co-housing projects could appear on different levels. The basic shared activity is to have residential assemblies even led by an outsider property-manager (Regular collective meetings) 69 ; in many cases, residents share the property management (Common property maintenance). 70 Everyday activities, like eating or housework can also take place in the community (Common daily activities). 71 Spontaneous encounters may occur during the use of the building (Spontaneous social interaction). 72 Organized shared events could be also observed, like educational, cultural events, and exercise classes (Social events within the community) 73 , besides, these events could be open to the neighbourhood (Activities open to the wider community). 74 It is also possible that inhabitants operate a service or produce something together (Community service or production). 75 The highest level of activity when inhabitants share a vision and work together to achieve it (Share vision or value). 76 The tenure or the ownership can be different in every country, and it also can depend on the special housing policy of cities -co-housing developments are not characterized by a typical tenure regime. In most cases, there is condominium 77 , that integrates private residents' ownership of housing units with a collective property of common spaces (The mixed form of ownership). 78 Other options are that the owner is an association (Collective non-profit organization, Residential cooperative and Common private society), whose members are all the residents 79 . There is absentee ownership in some cases, where the property is owned by the public sector or by the developer, but in other cases, the tenants can form a group (Shared rental). 80 Furthermore, there are some collective housing tenure networks around Europe, which ensure the independence of the real estate market (Urban housing network). 81

USER-ORIENTED, SHARING RELATED CO-HOUSING CATEGORIZATIONS
There are many possible aspects of urban housing development analysis. These analyses, both of individual housing and co-housing, lead to categorizations according to the main research aspects. In architectural and urban studies housing developments are often analysed by dwellings unit, residential buildings, or neighbourhoods, and they are categorized or typed by location, density, floor area, height, spatial design, technical solution, and other measurable properties. 82 For example, the well-known co-housing categories from Neufert were the low-rise or high-rise, the point block or slab block, and the masionettes 83 . Or, the contemporary a+t housing research group determined the housing types by their generic urban formation of the unit area: single-family houses, rowhouses, point buildings, double slab, slab, closed urban block, urban block with towers, plinth with towers and tower. 84 Co-housing is defined as housing with more shared characteristics than individual housing, therefore we are looking for user-oriented, sharing related categorizations that help to structure all co-housing developments more detailed by the user's sharing methods. User-oriented categorization is based on the methodology of "How to study public life" by Gehl and Svarre. 85 They worked out a questionnaire methodology to categorize the complex interaction of life and form in public space, which is extendable into housing analysis. They ask questions systematically and divide the variety of activities and people into subcategories to get specific and useful knowledge about the complex interaction of life and form in public space. These questions are about the users: how many (people), who (are the user), where (people use), what (are the people using), and how long (is the use)? This questionnaire methodology also appears in the housing analyses in Giorgi's categorization. He determined that the way in which people live in a shared environment depends on a lot of factors, which can mainly be related to these three categories: the reason why people look for this kind of shared living (Why), the level of sharing within the community (How) and the context in which the community is inserted (Where). 86 Tummers' article argues that co-housing can only be fully understood when taking into account planning context, therefore she analyses the cause (Why) and method (How) of the planning process. 87 Table 3. Characteristic categories of social sharing in co-housing sub-terms -in the order of the sharing level  86 Giorgi 2020. 110-111. 87 Tummers 2015a. 64-78. To categorize the type of co-housing Tummers defined some typologies, according to different sets of criteria, which are more about the users. The criteria are the following: Target group and residents profile (1), the distance to society (2), the degree of participation and self-management (3), community building (4), time and historical context (5), the approach to ecology and concept of sustainability (6), architecture and urban planning characteristics (7). 88 According to Tummers, co-housing is not just a housing form, it can also be a way for local identities under globalization, and to realize new forms of community, collaborative action, and make room for alternative values. 89 Connected to this statement based on Bresson and Sylvette, 90 Tummers categorized the international terms of co-housing developments into three groups, 'CO' as a community, 'AUTO' as collaborative action and 'ECO' as room for alternative values. 91 The previous three user-oriented categorizations are not fully addressed to the sharing. In contrast with these, Hemmens evaluated some type of co-housing by sponsorship and type of sharing. 92 He specified physical and social sharing features, tenure and rent sharing categories, and subcategories: room, bath/kitchen, common space (physical sharing), sociability, reciprocity, caretaking (social sharing), ownership, rental (tenure), rental mortgage, in-kind, subsidy (rent sharing). His methodology for the categorization is to define from a housing form if the subcategory is true or false for it. Hemmen's study is about affordable housing, where sharing methods and the tenure are interesting questions and can be varied, therefore he made a categorization to value the kind of shared housing. His categories and subcategories are specified to the affordable housing forms, so it is not a comprehensive categorization, but his methodology is significant in the topic sharing methods of co-housing. Based on this categorization and those obtained from our research, we categorize the co-housings sub-terms (with shared space) by the social fields of sharing (Table 3).

THE SHARING BASED VISUALIZATION OF CO-HOUSING TERMS
The summary of the main characteristics of co-housing sub-terms and sharing methods show the diversity of the existing shared features. The shared facilities and other shared characteristics in urban co-housing projects can appear on different levels. The features contained in the definitions are not covering all optional sharing methods, in addition to analysing definitions, it was also necessary to collect the levels of social sharing elements. Based on this collection we give a visualization of co-hous- 88 Tummers 2015b. 5-16;Tummers 2017. 133. 89 Tummers 2017. 57. 90 Bresson-Sylvette 2015. 91 Tummers 2017. 56-61. 92 Hemmens-Hoch-Carp 1996. 3-16. ing sub-terms according to the fields of sharing (Fig. 2). The terms in which spatial sharing is certainly present have been included in this visualized systematization, wherein the three previously defined social fields of sharing circles give the place to the terms. The division into levels of shared activities better highlights the differences and similarities between the terms (Fig. 3).

S H A R E D C R E
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CONCLUSION -THE SHORTCOMING OF A SHARING BASED CO-HOUSING CLASSIFICATION
The systematic approach of our term and literature overview goes beyond previous efforts in this field. This inductive method clarifies the use of terms and unfolds the connections between terms and definitions that were, until now, analysed form different aspects of the research fields. This paper unravels new perspectives on a categorization of the co-housing concept based on the sharing methods. Finally, this overview provides a collection of existing terms, definitions, and categorizations on urban co-housing, which can be used by the academic field to develop further models or theory.  Based on our findings, we would recommend future research to work out a sharing based co-housing classification, based on our systemization. Instead of subordinate co-housing projects under terms, we propose a classification that measurably classifies the sharing methods that appear in each project. The collection and visualization of the co-housing sub-terms in the order of social fields of sharing highlight that beyond the consistent use of terms there is also a need to clarify the relationship between physical and social dimensions based on case studies. Therefore, further studies could contribute to a clearer analysis of projects by developing a comprehensive classification system.