Recently, scholars have criticized the indiscriminate use of the term “social marginalization”, noting that it often is used to vaguely describe disadvantaged populations, thereby exacerbating stigmatization and exclusion (Munari et al., 2021). This concern is echoed by researchers who argue that the term is in dire need of clarification, to avoid the current connotation that socially marginalized individuals are inherently inferior or deficient, which could influence both research and policymaking (Causadias and Umaña-Taylor, 2018). Several major institutions, such as the United Nations, the World Health Organization, and the World Bank, produce reports and press releases on marginalization and propose strategies to combat it (e.g., Holzmann et al., 2020; United Nations, 2009; World Bank, 2013; World Health Organization, 2024). However, as highlighted by the United Nations (2009), these organizations face challenges in defining who is marginalized and in what way due to the absence of a universally accepted definition. In 2021, the verb “to marginalize”—defined as “to relegate to an unimportant or powerless position”—ranked among the top 1 percent of the most searched terms in a leading online dictionary (Merriam-Webster.com Dictionary, 2021). The terms “social marginalization” and “socially marginalized groups” keep gaining significant prominence in the academic literature (Baah et al., 2019; Hall and Carlson, 2016; Vasas, 2005). Moreover, despite this lack of clarity, significant public spending continues to target efforts to reduce social marginalization (Breidahl and Clement, 2010). This ambiguity is problematic; without a clear understanding of who is considered socially marginalized and in what respect, there is a risk that certain groups may not receive the support they need, adversely affecting their livelihoods.

Paradoxically, the wide academic interest in social marginalization might have inadvertently obscured its meaning, complicating our understanding of who is affected, as well as how and where (Kerr and Jackson, 2016). The multitude of research perspectives and different types of operationalizations of social marginalization tend to rather blur than clarify the field. Specifically, attempts to address marginalization without providing a definition can erode the concept, which may lead to operationalization problems, ambiguous findings, and incomparable results (Vasas, 2005).

Our aim, therefore, is to conduct a scoping review to comprehensively map 50 years of scientific literature on social marginalization, spanning from its initial introduction in the twentieth century to the present. This approach is ideal, as scoping reviews aim to provide a systematic overview of a body of literature that is complex or heterogeneous in nature and/or has not yet been comprehensively reviewed (Peters et al., 2015; Pham et al., 2014). Moreover, scoping reviews serve as the preferred methodology for clarifying key concepts and definitions in existing literature and identifying key characteristics related to a concept as we aim to accomplish for the concept of social marginalization (Peters et al., 2020).

Currently, only two review studies and one discussion paper on marginalization are available (Baah et al., 2019; Causadias and Umaña-Taylor, 2018; Vasas, 2005). The key findings of these studies revealed that marginalization is a complex process where certain groups of individuals face structurally restricted access to resources, resulting in varying degrees of differential treatment. While both reviews narrowly focus on nursing research, one of them is already almost 20 years old (Vasas, 2005), and the second limited to papers between 2007 and 2018 (Baah et al., 2019). Moreover, the Causadias and Umaña-Taylor (2018) discussion paper focused specifically on youth development and does not include a systemic attempt to review scientific efforts in this field. Therefore, there is a lack of reviews examining the use of the term social marginalization in all research contexts over a more extended period, from its inception to the present (Munari et al., 2021). The relevance of social marginalization extends beyond the nursing discipline, with implications spanning across diverse fields such as education, the labor market, public health, and policymaking. The concept is also linked to negative intergroup attitudes, stereotyping, and discrimination (Hall and Carlson, 2016). As its prominence as a research topic keeps growing, there is a pressing need for a comprehensive, up-to-date review. Our study fills this gap, covering all scientific disciplines to offer a comprehensive overview of social marginalization research.

We set out to analyze over 50 years of publications on social marginalization identified in two major, general scientific databases. Our aims are twofold. First, we aim to define social marginalization by extracting, analyzing, and synthesizing definitions used in existing research. Second, we aim to examine how social marginalization is used in the literature by identifying the social groups, life domains, and countries studied, as well as observing time trends. Adhering to the newest standards of scoping reviews, i.e., the Preferred Reporting of Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for Scoping Reviews (Tricco et al., 2018), our study addresses key questions about research on socially marginalized people. By doing so, we aim to clarify the terminology, guide future research on suitable operationalizations, and provide policymakers with insights for targeted interventions.

Method

Analysis

To identify relevant literature and extract data for our research questions, we adopted the team-based scoping review methodology of Levac et al. (2010), a widely applied approach based on Arksey and O’Malley’s (2005) initial methodological framework for scoping reviews. The method comprises five stages: identifying the research question, identifying relevant studies, selecting studies, charting the data, and reporting the results. In line with the required standards for scoping reviews (Peters et al., 2015), our study involved multiple reviewers and was preregistered (Fluit et al., 2021). The protocol, including the research questions, is available at https://osf.io/9u8bp/. Additionally, we examined the use of the term “social marginalization” by major transnational organizations for whom the concept is particularly relevant.

Identifying relevant studies

We conducted our literature search using Scopus and Web of Science, two of the most comprehensive databases for scientific publications across all disciplines. Google Scholar was not used due to its inclusion of non-peer-reviewed and non-English-language materials (Martín-Martín et al., 2018). Following the Joanna Briggs Institute methodology for systematic reviews (Peters et al., 2015), we employed a three-step approach for identifying relevant studies: First, after a preliminary search in Scopus to evaluate the search terms, a comprehensive search was performed in both databases by a librarian. The full search terms were: “TITLE-ABS(“social* marginali*”) OR AUTHKEY(“social* marginali*”)”. We limited the search to peer-reviewed journal articles and review papers in English, with no limitations on scientific discipline or publication year. The final search was conducted in April 2021. Second, duplicates were removed using EndNote version 20. Third, we searched in the reference lists of articles defining social marginalization to identify further relevant reports.

Selection of relevant studies

For the selection of relevant studies, we adhered to the PRISMA guidelines (Moher et al., 2009; Page et al., 2021) as illustrated in Fig. 1. In Rayyan, a specialized screening tool for reviews (Ouzzani et al., 2016), the first author and a research assistant independently screened the identified records against the eligibility criteria (outlined in Table 1), consulting the two co-authors in case of disagreements. The entire research team discussed decisions concerning eligibility regularly. Based on the participants-concept-context approach suitable for scoping reviews (Peters et al., 2020), our inclusion criteria were: (1) all studies addressing human-related social marginalization, (2) any mention of social marginalization qualified a study for inclusion, and (3) studies from all countries were eligible. Recognizing the iterative nature of scoping reviews, we refined our criteria by excluding studies focusing on pre-twentieth-century marginalization and analyses of fictional marginalization, such as in novels and films.

Fig. 1: PRISMA Flow Diagram for Article Selection.
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Note. aReasons for exclusion: fiction analysis (N = 55), wrong time period (N = 33), wrong language (N = 19), wrong outcome (N = 19), wrong population (N = 4), wrong publication type (N = 3), not peer reviewed (N = 2). 19 papers were excluded for more than one reason. We identified 87 papers with a definition among the 1121 papers and through manual search identified 10 more papers with a definition, resulting in N = 97.

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Table 1 Eligibility criteria.
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Data charting

Our data charting also followed a three-step process (Levac et al., 2010). First, the first author and a research assistant extracted key general information from the papers, including the frequency of mentioning social marginalization, research design, journal of publication, and publication year. Time trend analysis was based on publication year as compared to the general output of scientific research annually in Scopus, allowing us to evaluate the growing prominence of social marginalization in research. Second, the papers were manually categorized based on the socially marginalized group under study, the topic of marginalization, and the country or region. This categorization was performed by the first author and a research assistant, and doubts and disagreements were solved in cooperation with the second author. Third, the first author scanned all papers for definitions of social marginalization, which the first author subsequently extracted and analyzed using NVivo, a software tool for qualitative data analysis (QSR International Pty Ltd., 2020). Through inductive grouping, these definitions were organized into themes, following the renowned methodology for qualitative content analysis by Hsieh and Shannon (2005). This last step was initially conducted by the first author and then discussed and revised with the two co-authors.

Results

The scoping review yielded 1295 deduplicated records. After screening them against our exclusion criteria, the final study selection resulted in 1121 papers (a list of included papers is available at https://osf.io/9u8bp/).

In our review of 1121 papers, “social marginalization” was mentioned a total of nearly 13,000 times, with mentions per article ranging from once to 157 times (M = 11, SD = 15). While 96 papers mentioned the term only once, eight papers used it more than 100 times. Papers were published across 781 different journals, predominantly in the health sector. BMC Public Health was the most frequently occurring journal with 14 articles, followed by Social Science & Medicine with 13, and the International Journal of Drug Policy with 10. Methodologically, studies were mainly qualitative (N = 403) or quantitative (N = 350) analyses of primary data. Of all papers, 220 reviewed secondary data, 80 papers were non-empirical, and 68 papers employed other research designs, such as mixed methods or case studies.

Geographical locations of social marginalization research

Even though 120 unique countries or territories were studied, the United States, Canada, and the UK were overrepresented (see Fig. 2, Panel A): Overall, 60% of the studies focused on North America and Europe, 12% on Asia, 8% each on Latin America and Africa, 5% on Oceania, and 3% on the Middle East. The majority of studies were conducted within a single country, and 97 papers did not cover a specific territory.

Fig. 2: Geographical locations, frequency development, groups, and topics of social marginalization research from 1970 to 2020.
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Note. Panel a highlights the geographical locations under study in the identified records. The geographical location ‘other’ refers to papers with more than one location or without a specific location. Panel b refers to the publication years of the records. 2021 is not present as the data collection stopped in April 2021. Panel c visualizes the groups under study in the records. Panel d shows the topics of social marginalization mentioned in the records.

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Time trends in social marginalization research

Our time trend analyses showed that social marginalization research gradually grew from the 1970s onwards, with a significant exponential increase in the 2010s (see Fig. 2, Panel B). The earliest article in our database dated back to 1966. In the 1970s and 1980s, only 17 papers on social marginalization were published. This number rose to 60 in the 1990s and further to 224 in the 2000s. The most notable increase occurred in the 2010s, with 637 papers addressing social marginalization. When adjusted for the overall growth in the scientific literature, social marginalization’s share of the total scientific output increased from an average of 0.0021 per mille in the 1970s to 0.0368 per mille in the 2020 s, an 18-fold increase. The peak year of publications was 2020 (the last full calendar year included in our analyses as data collection stopped mid-2021), with 152 academic papers mentioning the term social marginalization.

Groups in social marginalization research

In our analysis of the 1121 papers, we categorized the groups studied. About 60% of the papers focused on a single group, while the remaining 40% examined intersecting groups (e.g., immigrant girls) or compared groups (e.g., HIV among homeless people and trans women). A total of 162 papers did not study a particular group, and 54 papers had a non-human unit of analysis, such as neighborhoods, schools, or countries. Initially, we identified 46 distinct groups, which we brought together in 12 clusters (see Fig. 2, Panel C). The most frequently occurring cluster of people—immigrants or ethnic, racial, or religious minorities—was examined in 365 papers, whereas the least frequently occurring cluster was brought up in 15 papers. In descending order of frequency, the clusters were: (1) immigrants or ethnic, racial, or religious minorities, (2) people with health issues (disease, disability, or addiction), (3) people with low socio-economic status, (4) young people, (5) women, (6) LGBTQIA+ people, (7) people in rural areas, (8) (formerly) incarcerated people, (9) the elderly, (10) sex workers, (11) people with high body weight, and (12) victims of abuse.

Next, we examined whether the identified clusters were studied in various countries and geographical contexts, or whether certain clusters were predominantly studied in specific regions. The results showed that social marginalization related to people with a low socioeconomic status was a consistent focus of studies across all regions worldwide. Moreover, people with health issues (i.e., diseases, disabilities, and addictions of various sorts) were studied in all continents, as well as LGBTQIA+ individuals. Yet, other clusters were primarily investigated within specific geographical contexts. In African countries (i.e., Burkina Faso, Cote d’Ivoire, Ethiopia, Ghana, Kenya, Senegal, Tanzania, Uganda), research often focused on the social marginalization of women. In settler-colonialist countries such as Australia, Canada, Mexico, and Chile, a considerable number of studies centered on the marginalization of Indigenous people, a group rarely examined outside these regions. Indigenous people were classified as part of the wider cluster of immigrants or ethnic, racial, or religious minorities.

In Europe (i.e., Denmark, the European Union, Italy, Norway, Poland, Portugal, the UK), studies frequently focused on the cluster of immigrants or ethnic, racial, or religious minorities, of which specifically Roma people, immigrants, and refugees. Additionally, European research more often addressed people with health issues—ranging from physical health, disabilities, to mental health problems—especially in adolescent populations.

Social marginalization in relation to Black people, people of color, and African Americans was a specific focus in US studies, again typified under the cluster immigrants or ethnic, racial, or religious minorities. Several other countries studied their own social marginalization challenges such as individuals from lower castes in India, orphans in Japan, the clergy in Vatican City, rurally living people in China, and war victims in Ethiopia. Studies with a global perspective frequently highlighted the Global South, and specifically Africa (without specification) or particular African countries as socially marginalized.

Topics in social marginalization research

We assigned a total of 3441 topic labels across the 1121 papers, identifying 103 unique topics. Most papers addressed multiple topics (e.g., poverty combined with mental health). We then categorized these topics into 17 clusters. The most frequently studied topics included marginalization related to (1) health, (2) socio-demographic characteristics (employment status, educational attainment, gender, ethnicity, etc.), and (3) discrimination and segregation (see Fig. 2, Panel D). Other topics frequently examined were marginalization involving (4) institutions (educational system, welfare state, the police), (5) culture and identity, (6) social relationships, (7) political attitudes, (8) violence and crime, and (9) agriculture and climate. Less common topics were (10) substance use, (11) urban marginalization, (12) social justice, and marginalization around (13) sex, (14) migration, and (15) resilience. The least common topics were (16) marginalization in research and academia and (17) digital marginalization. A more detailed description of each of these topics is provided in Table 2.

Table 2 Description and Count of Topic Clusters in Social Marginalization Research.
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Definitions of social marginalization in research

Among the 1121 papers reviewed, we identified 87 studies that provided a definition of social marginalization. We additionally identified 10 papers through the reference lists of the 87 papers resulting in N = 97 (see Fig. 1). These definitions were then categorized into four thematic clusters, which are detailed in the subsequent sections: (1) The other: Definitions originating from migration research, (2) Margo: Spatial definitions, (3) Lacking: Characteristics of socially marginalized persons, and (4) Experience: Subjective, intersectional, and multifaceted marginalization.

The other: definitions originating from migration research

One cluster of conceptualizations centered around definitions originally coined by migration researchers. Within this framework, social marginalization was closely tied to individuals navigating moving between cultures, notably refugees and immigrants, who were believed to encounter psychological challenges during cultural transitions. Initially linked to foreigners, the concept of social marginalization gradually expanded to encompass other groups of “others”, including working women, Black people, and Indigenous Americans. Over time, as highlighted by Arrington-Sanders et al. (2020) and Glover et al. (2020), the understanding of socially marginalized groups evolved to include a broad spectrum of socio-demographic categories, marked by distinctions in gender, age, class, race, disability status, sexual orientation, socioeconomic status, and more. In sum, a marginalized individual presented characteristics that set them apart.

Definitions in this tradition highlighted the role of social norms in processes of marginalization (Burton, 2019; Glover et al., 2020; Zelano, 2019). Specifically, definitions emphasized the importance of being identified as the “other” by diverging from accepted ways of thinking, speaking, and being (Burton, 2019: 6). In the same line of thinking, Zelano (2019: 376) argued to define marginalization in terms of “transgressing” accepted social norms. Moreover, given that social norms differ throughout time and place, definitions of social marginalization were thought to be context dependent. Glover et al. (2020) illustrated this by suggesting that lesbian, gay, and bisexual individuals became less marginalized with the widening of societal norms regarding sexual attraction. Moreover, institutions, such as the educational and legal systems, the police, and the welfare state were attributed a crucial role in establishing and upholding these norms, effectively reinforcing the categorization of certain groups as the “other.” This notion has been referred to as “structural marginalization” (Arrington-Sanders et al., 2020: 7). Crucially, being the “other” not only meant being different but also being inferior, less important, invisible, voiceless, and unwanted (Arrington-Sanders et al., 2020; Buchta and Štulrajter, 2008; Ecks and Sax, 2005; Juliano, 2016; Knoke, 1972; Lockyer, 2010).

To sum up, one cluster of definitions, originally derived from migration research, has evolved from its initial association with being a “foreigner” to a broader interpretation as the “other” in various contexts, emphasizing the theme of deviation from societal norms.

Margo: spatial definitions

In contrast to migration researchers, another group of authors conceptualized marginalization primarily in geographical terms (Andrews-Speed and Ma, 2008; Birnholtz et al., 2020; Buchta and Štulrajter, 2008; Ecks and Sax, 2005; Lombard, 2015). For example, Birnholtz et al. (2020: 2) stated that “marginality and geography have long been intertwined, with unequal access to resources such as prime land or urban cores often a precursor to social, economic, or geographic marginality.” In this tradition, marginalization is traced back to the original Latin meaning of “margin” (margo), denoting a border or edge. Researchers in this domain commonly used metaphors such as “on the edge of society,” “in the periphery,” or “in the margins” to describe marginalized groups (Anttonen, 2008; Bjerge et al., 2020; Buchta and Štulrajter, 2008; Gidron and Hall, 2020).

Importantly, this approach viewed marginalization as a social construct, asserting that margins only can be defined in reference to a center. Ecks and Sax noted that marginalization is “a thoroughly relational term because people and places are defined as ‘marginal’ only in relation to a ‘center’” (2005: 200). Relatedly, some researchers, such as Hall and colleagues (1999; 1994; 2016) highlighted social marginalization as a process. Hall and Carlson (2016: 202) defined marginalization as “a process by which persons or groups are socio-politically peripheralized from dominant, central experiences, that is, deprived of mobility, control over self-will, and/or critical resources, indignified and humiliated, exposed to toxic environments, and/or exploited physically or mentally.” Similar to the migration definition-theme, marginalization is considered to be a concept emphasizing the dynamic and fluid division between mainstream society and the margins (Glover et al., 2020). However, there is inconsistency among researchers concerning how far removed from the center marginalized individuals are considered to be. Some placed them in the liminal space between full inclusion and exclusion (Breidahl and Clement, 2010), whereas others positioned them at or even beyond society’s boundaries (Alexander et al., 2003; Anttonen, 2008).

In short, social marginalization according to the spatial approach is understood as a socially constructed, shifting dynamic between a symbolic center and the margins, where being in the margins often entails limited access to resources.

Lacking: characteristics of socially marginalized persons

In a majority of definitions of social marginalization, marginalized persons were characterized as “lacking” something, typically resources (Andrews-Speed and Ma, 2008; Arrington-Sanders et al., 2020; Chaves et al., 2008; Gastrow et al., 2017; Lockwood, 1997). Depending on the particular emphasis of the definitions, researchers additionally described marginalized people as lacking agency, belonging, social control, social interactions, respect, opportunities, freedom, well-being, or connections with institutions (Chen et al., 2015; McClure, 2007; Nørup, 2020; Pedersen et al., 2020; White, 1993). Moreover, the concept of power received special attention in many papers, framing social marginalization as a deficiency in political or societal power (Burton, 2019; Cummins, 2015; Dawson, 2001; Ecks and Sax, 2005; Exner-Cortens et al., 2021). Marginalization was commonly conceptualized as either a cause or consequence of power discrepancies in society (Mcintosh, 2006). Thus, marginalized persons were described as having limited access to resources and as being negatively affected by the inequal distribution of wealth.

Experience: subjective, intersectional, and multifaceted marginalization

Whereas most papers defined social marginalization as an objective, measurable condition (e.g., poverty, homelessness), a limited number of papers explored the subjective experiences of marginalization. Typically, these papers emphasized the importance of the perception of marginalized people themselves, noting that not all members in a marginalized group perceive or experience marginalization in the same way (Knoke, 1972: 29). It may as such be possible for people to not feel marginalized even though they are classified as such by researchers (Breidahl and Clement, 2010). Authors who adopted this subjective viewpoint in their definition often highlighted that social marginalization is multifaceted and layered, affecting multiple areas of life simultaneously (Arrington-Sanders et al., 2020; Jensen and Larsen, 2021; Mattalia et al., 2018; McClure, 2007; Ramírez-Tirado et al., 2019). Some argued that an accumulation of problems can intensify the degree of marginalization, leading to compounded risks (Glover et al., 2020). Others focused on intersectionality, suggesting that marginalization experiences are not uniform and vary across groups. For instance, Jensen and Larsen (2021) observed that Muslim women and men in Europe experienced Islamophobia differently due to the intersection of religion and gender. Consequently, authors proposing an intersectional approach to social marginalization emphasized that all experiences of marginalization are unique and dependent on multiple characteristics of a person (Arrington-Sanders et al., 2020).

In summary, definitions emphasizing subjective experiences stressed that while specific groups may be identified as marginalized by researchers, the individuals within these groups may not necessarily perceive themselves as such. Furthermore, among those who do acknowledge their marginalization, the nature of their experiences can vary across groups and differ based on the individuals’ unique intersections of attributes.

Use of the concept of social marginalization in selected grey literature

Before offering a unified definition of social marginalization based on academic work, we provide an overview of how the term is used in policy papers, press releases, and other materials produced by major transnational organizations for whom the concept is particularly relevant. We identified the United Nations, UNESCO, the World Health Organization, the World Bank, Save the Children, Unicef, FRA – the European Union Agency for Fundamental Rights, the Red Cross, and the OECD as key organizations in this respect.

Crucially, several organizations highlighted the lack of a unified definition, noting that there is rarely a consensus on what constitutes social marginalization, especially one that is applicable across countries (UNESCO, 2010; United Nations, 2009, 2017). Of the organizations reviewed, only UNESCO provided a specific definition, though limited to the context of education. UNESCO defined marginalization as a “quantitative deprivation, as measured by years in school or the level of education attained”. The UNESCO report further emphasized that marginalization in education also has a qualitative dimension, where the “marginalized typically demonstrate low levels of educational achievement”. And it further stressed that “in all countries, whatever their level of development, some individuals and groups experience extreme and persistent disadvantage in education that sets them apart from the rest of society”. The report also noted that this disadvantage is both the cause and an effect of marginalization and a transmitter of marginalization across generations. In a working group meeting paper, the United Nations (2009: 1) defined marginalization as “a form of acute and persistent disadvantage rooted in underlying social inequalities”.

Most did not offer a formal definition but instead identified specific groups they considered socially marginalized, including girls and women, the elderly, children, adolescents, and young people, Indigenous people and ethnic minorities, poor households, people living in informal settlements or those internally displaced, war victims, individuals with disabilities, rural and nomadic populations, and those affected by HIV and AIDS (e.g., FRA - European Union Agency for Fundamental Rights, 2010; OECD, 2011; Unicef, 2021; World Bank, 2013; World Health Organization, 2024). It was frequently noted that intersections or combinations of these identities or factors increase the degree of marginalization experienced.

An integrated definition of social marginalization

We integrated the four definition themes from the academic literature and suggest defining social marginalization as: a multifaceted concept that refers to a context-dependent social process of “othering”—where certain individuals or groups are systematically excluded based on societal norms and values—and the resulting experience of disadvantage. As such, social marginalization comes with restricted access to resources such as education, healthcare, and employment, while increasing exposure to various adverse socio-structural life outcomes, including poverty, discrimination, and social isolation. Crucially, both the process and outcomes of social marginalization can vary significantly across diverse social, cultural, and historical contexts.

Discussion

In this scoping review, we identified how the concept of social marginalization has been defined and used in over 50 years of scientific research. From our examination of 1121 papers on social marginalization identified in Scopus and Web of Science, we explored the concept as it pertains to 12 distinct groups of people and 17 topics, predominantly in the contexts of Europe and North America, using both theoretical and empirical research designs. A significant number of papers referenced social marginalization to underscore the societal relevance of their research, yet often, a precise definition of the term was not provided. While a majority of the identified papers acknowledged their focus population as socially marginalized, in-depth analyses of the reasons and mechanisms behind this marginalization were frequently absent. Only 97 papers provided a definition of social marginalization, and we identified the following four themes: migration research definitions, spatial definitions, characteristics of socially marginalized persons, and marginalization as a subjective experience. Taking this diversity in definitions into account, our review illustrates that social marginalization is a complex, heterogenous concept that is understood in a multitude of ways by the research community.

It is notable that while many papers described socially marginalized people as deviating from a norm, surprisingly few articles provided a clear description of this norm. Considering the wide range of 17 groups identified as socially marginalized, norms will be highly context-dependent. For example, women may be socially marginalized in male-dominated environments but not necessarily in other contexts. Indeed, the notion of a definitive, non-marginalized group is elusive. This group, often idealized as White, male, European, or North American, cisgender, heterosexual, able-bodied, addiction-free, well-educated, middle- to upper-income, and residing in central locations has previously been termed a mythical norm (Lorde, 1984). Thus, as social marginalization has the potential to affect almost all individuals in society, we emphasize the indispensability of a clear and operationalizable definition for this highly relevant concept for both science and policymaking.

We integrated important aspects of all four definition themes into our definition of social marginalization. The critical element of the “other” and “othering” was derived from the migration research theme. Social norms play a crucial role in determining who the “other” is and in outlining how and to what degree that individual or group stands out as “different”. From the theme focusing on the characteristics of marginalized persons, we underline the disadvantaged nature of this otherness as central to social marginalization. The dynamic aspect of this process stems from the spatial theme, which suggests that the margins are a relational space, existing only relative to a center. What constitutes this center, where it is located, and who resides in it are all context-dependent. While common themes of marginalization exist globally, many locations have their own specific socially marginalized groups and processes, shaped by local conditions. Finally, in line with the definition theme emphasizing subjective experiences, our definition recognizes the deeply subjective and intersectional nature of the marginalization experience.

Limitations

This preregistered scoping review assessed over 50 years of research on social marginalization and reviewed more than a thousand papers. The review thus provides an extensive overview of conceptualizations of social marginalization and suggests an integrated definition of the term that can be used in future research.

Our results must be interpreted in the light of several limitations, however. First, while our review included a significant body of literature on social marginalization, it was limited to works published in English. In line with previous suggestions for scoping reviews, we did not include master’s and doctoral theses, conference proceedings, book chapters, or a rigorous analysis of grey literature (Webster et al., 2017). Although we extended the scope of analyses by also including materials from key transnational organizations for whom the concept is particularly relevant, we did not provide a full analysis of the grey literature in the field (Benzies et al., 2006). Future studies should provide a particular focus on exploring how social marginalization is defined in non-academic fields and compare such definitions to those identified in our study. Second, we did not examine related concepts such as social exclusion (Peace, 2001). Future scientific attention should therefore be directed towards exploring the use of such related concepts and how they differ conceptually from the term social marginalization. Third, this review represents an initial attempt to clarify the term social marginalization. As a result, the proposed clusters of topics and groups were derived inductively, suggesting that alternative interpretations and combinations of these elements are possible. This highlights the need for ongoing scholarly investigation to further refine our understanding of social marginalization. Fourth, the meaning of social marginalization, as well as the groups and topics studied, are context dependent. While we included some country- and region-specific analyses and identified several social marginalization processes specific to certain contexts, our review does not provide a detailed, in-depth examination of regional nuances. Future research should place greater emphasis on the differences between and within regions and countries.

Implications for research and practice

Throughout this review, we identified two important gaps in existing research on social marginalization. First, while the phrase “socially marginalized” is frequently used by researchers and policymakers to denote disadvantaged groups, there is limited understanding of how individuals from these identified communities perceive and experience social marginalization themselves. We recommend that future research efforts be directed towards developing tools to assess perceived social marginalization across various domains. Research incorporating self-perception metrics could significantly enhance our understanding of the subjective and perceptive aspects of marginalization, which has been understudied. These tools could also help identify groups in society that experience marginalization but are not currently recognized as such by researchers.

Second, we suggest future research to explicitly define what they mean by social marginalization and to clearly delineate the social and geographical context of the individuals they consider marginalized. As our review demonstrates, social marginalization is context dependent and dynamic. Understanding the specific context of marginalization is crucial to gain insights into the mechanisms causing social marginalization. Future research would benefit from adopting an intersectional perspective and expanding the scope of study to include more countries. Such an approach would allow for a more nuanced understanding of social marginalization.

Conclusion

Based on the analysis of 1121 papers, we find that the social marginalization research field has been expanding exponentially over the past 50 years covering a wide range of topics and groups, albeit focusing mostly on North America and Europe. We propose that social marginalization is defined as a multifaceted concept that refers to a context-dependent social process of “othering”—where certain individuals or groups are systematically excluded based on societal norms and values—and the resulting experience of disadvantage. We posit that a consistent and clear definition of social marginalization, such as the one suggested, is essential. This clarification aids researchers in understanding why certain groups are identified as socially marginalized, the specific context of their marginalization, and how to understand their personal experiences with social marginalization. Future studies are needed to evaluate and expand upon our proposed definition. By doing so, we can advance this field of study and identify strategies to address social marginalization, with interventions ranging from individual to global levels.