Religious identity in the workplace: A systematic review, research agenda, and practical implications

We conducted a systematic review of relevant literature to address how religious and occupational identities relate to each other in the workplace. We identified 53 relevant publications for analysis and synthesis. Studies addressed value differences associated with religion and occupation, identity tensions, unmet expectations, and the connection of religious identity to well-being and work outcomes. Key variables in the connection between religious and occupational identities included personal preferences, the fit between religious identity and job-related concerns, and the organization's policies, practices, and expectations. We highlight the personal and organizational consequences of being able to express religious identity at work and the conditions that promote high congruence between religious identity and its expression in the workplace. From these findings, we develop a research agenda and offer recommendations for management practice that focus on support for expression of religious identity at work while maintaining a broader climate of inclusion.


| INTRODUCTION
Religious beliefs can profoundly affect how employees do their jobs. In the United States, nearly 80% of individuals are religiously affiliated (Pew Research Center, 2015), and in England and Wales, 68% (Office for National Statistics, 2012), suggesting a large segment of the workforce may identify with a religion. Yet, religious identity in the workplace is often neglected in human resource (HR) theory and practice, making it a workplace diversity issue prone to tension and conflict (Gebert et al., 2014). In 2014, the case of two Catholic midwives seeking to avoid supervising abortion procedures reached the UK's Supreme Court, which ruled against them (BBC News, 2014). In 2017, in response to the firing of a Muslim receptionist, the European Court of Justice ruled that workplace bans on wearing hijabs need not constitute discrimination (BBC News, 2017). Recently in the United States, several retail pharmacy chains faced public backlash after some pharmacists declined to fill prescriptions they deemed against their religious beliefs (Turesky, 2018). These events have prompted media attention and public debate, pointing to potential conflicts between the expression of occupational and religious identities.
[The copyright line for this article was changed on 23 October 2019 after original online publication.] Religious identity is tied to an array of important workplace outcomes. It can inform and enhance an individual's workplace decisions and contributions when there is a clear connection between occupational and religious values and behaviors (e.g., Morrison & Borgen, 2010). On the other hand, tensions between religious and work identities can adversely affect employee well-being and other individual outcomes (Ghumman, Ryan, Barclay, & Markel, 2013). Nonetheless, the intersection of religion and the workplace is not widely studied in either HR or organizational research (Lynn, Naughton, & Vander Veen, 2010). For this reason, there are calls for more investigation of the relationship of religion with discrimination in the workplace (Cantone & Wiener, 2017), work-related stress (Brotheridge & Lee, 2007), diversity practices (Gebert et al., 2014;Stone & Stone-Romero, 2002), and attitudes toward work (Stone-Romero & Stone, 1998).
We seek to advance research and practice related to workplace diversity by analyzing a neglected facet of diversity research, religious identity in the workplace. We do so through a systematic review (SR) of the relevant though fragmented literature in management, psychology, sociology, and occupational studies. SR is a "key methodology for locating, appraising, synthesizing, and reporting the best evidence" (Briner, Denyer, & Rousseau, 2009, p. 4). We undertake a methodical examination of existing literature to synthesize available evidence on the positive, negative, and neutral impact that religious identity can have on workplace decisions and behaviors.
Our review makes four contributions. First, through a systematic literature review, we advance understanding of the relationship between work and nonwork identities and its implications for individuals, workgroups, and organizations. Second, our review yields an organizing framework that explicates the relationship between religious identity and occupational identity in terms of the fit or congruence between them. This framework helps identify the antecedents and consequences associated with this congruence and calls attention to the role of religious identity as an important workplace dimension with respect to person-environment fit (c.f., Milliman, Gatling, & Bradley-Geist, 2017).
Through our review and resulting framework, we contribute to theory and practice related to workplace diversity by explicating how, when, and with what consequences religious identity is compatible or incompatible with the workplace. In doing so, we respond to Lynn et al.'s (2010) call for research to address gaps in our understanding of workfaith integration and its implications for organizations. Third, based on our findings we offer direction for future research to stimulate more systematic investigation of religious identity and its potential multilevel workplace dynamics. Fourth, we expand the standard conceptualization of workplace diversity by linking religious identity and its important deep-level implications for diversity management. In doing so, we provide advice for practice regarding how to promote more inclusive organizations with respect to religious and other identities.
In the sections that follow, we first define key terms, explicate the connection religious and occupational identities have to the workplace diversity debate, and present the specific questions that guide our SR. Next, we specify our review methodology and detail our findings. Finally, we identify a research agenda and the implications of our findings for management practice.
We define identity as how an individual thinks about, understands, and judges her/himself as a social being. Identity incorporates the interests, values, abilities, and norms a person ascribes to the self in the context of a social role, such as the occupation of a professor or a nurse or the religious faith of a Christian or a Muslim (Ashforth & Mael, 1989;Tajfel & Turner, 1979). Narrowly formulated, the components of identity are cognitive (I am), evaluative (I value), and emotional (I feel about). In a broader sense, identity has both content (e.g., values and beliefs) and associated behaviors (e.g., routine practices; Ashforth, Harrison, & Corley, 2008;Tajfel & Turner, 1985).
Religious and occupational identities constitute a deep structure comprised of both conscious and unconscious processes that underlie the individual's broader self-concept (Rousseau, 1998), a self concept both individually crafted and shaped by relations with others (Breakwell, 2001;Dutton, Roberts, & Bednar, 2010;Tajfel & Turner, 1979). Although identity can be thought of as an individual's socially shaped response to the question "Who am I?", it also reflects a collective's answer to the question "Who are we?" (Horton, Bayerl, & Jacobs, 2014).
Our conceptualization of identity draws upon social psychological theories, such as theories of social identity (Tajfel & Turner, 1979, 1985 and self-categorization (Turner, Hogg, Oakes, Reicher, & Wetherell, 1987), collectively termed "the social identity approach" (Haslam, 2004). According to social identity theory, people identify with social groups and categories that fit their self-perceptions, providing a sense of pride and self-esteem. Social identities derive from the social categories (e.g., gender, ethnicity, class, religion) with which individuals identify. Self-categorization theory explicates the nature of category membership (voluntary or prescribed), and its boundaries (ingroups and outgroups). As argued by Brewer (1991) in her optimal distinctiveness theory, individuals seek to integrate their various identities so that they experience both belonging (e.g., to important groups like religions or ethnicities) and distinctiveness (e.g., to differentiate their personal contributions and attributes from others). These social psychological theories underpin our conceptualization of identity as a coconstruction among communities, groups, and individuals.
In the workplace, many identities can exist in relation to careers, teams, organizations, and occupations (Ashforth et al., 2008;Miscenko & Day, 2016). We focus on occupational identity (Ashforth & Mael, 1989;Skorikov & Vondracek, 2011)-the sense of self as a member of a profession, typically via education, training, and/or work duties (e.g., nurse or police officer). This concept is broader than organizational identity (e.g., as a company's employee) and more specific than work identity (i.e., meanings attached to the self by the individual and others in the work context; Miscenko & Day, 2016) though it overlaps with each. Occupational identity contributes to the emergence of meaning and structure in personal lives (Skorikov & Vondracek, 2011), influences social status and role behavior (Kreiner, Hollensbe, & Sheep, 2006) and is shaped by institutions beyond the employer such as professions and educational organizations (Skorikov & Vondracek, 2011).
Religious identity derives from a sense of affiliation with a religious group and incorporates the beliefs, values, and practices of that group (Ysseldyk, Matheson, & Anisman, 2010). In defining religion, Loewenthal (1995) identified several beliefs shared by major religious traditions: the existence of a nonmaterial (spiritual) reality; life's purpose as increasing harmony in the world by doing good and avoiding evil; and, in monotheistic religions, a belief that the source of existence (God) is also the source of moral directives. Importantly, all religions involve and depend on social institutions, giving rise to a sense of affiliation with a group (Loewenthal, 1995). The institutional nature of religion is highlighted by its endemic role in certain work settings.
For example, staff may be required to hold a particular religious identity as in the case of teachers in a yeshiva or parochial school while employees can decide whether to disclose their religious identity in other settings. Importantly, religions function in a social context, where some may be approved and others stigmatized. For example, in the United States an emphasis on Christian identities and the embedded nature of the Protestant work ethic make the two highly compatible, whereas Islam is more stigmatized and might be seen as less compatible with some work identities (Arslan, 2001;Mujtaba, Cavico, & Senathip, 2016;Sanchez-Burks, 2002).
Several other concepts overlap religion and religious identity. The broader notion of "belief system" refers to deeply held values including but not limited to those associated with religion (Stone & Stone-Romero, 2002). For example, some argue that Buddhism is a belief system but not a formal religion given the absence of a theistic creator. However, due to its formalized teachings, rituals and what often appears to be the worship of the Buddha, Buddhism is widely seen as a formal religion (Gethin, 1998;Herbrechtsmeier, 1993). Another related concept is spirituality. More difficult to define than religion, spirituality contains dimensions related to meaning and purpose in life; a mission or life calling; a transcendent dimension involving external and internal factors such as deities, spirits, inner guides, or higher selves; an emphasis on wholeness and connectedness; the notion of an essential and perhaps eternal soul; and a belief in personal transformation (Coyle, 2008). Parts of the Western world have shifted from religion toward spirituality (Woodhead & Heelas, 2004). Although overlapping in some aspects, religious identity is distinct from spirituality in that the former is connected to specific tenets and usually to an organized social group or institution, while the latter tends not to be. Although religion overlaps with concepts of belief system and spirituality, our focus is on religion and specifically religious identity.
Religious identity differs from other forms of identity in the affective experiences and moral authority associated with religion. A search for the sacred is said to distinguish religion and spirituality from other phenomena (Hill et al., 2000), but it is the self-transcendent and often supernatural form of "the sacred" that makes religious identity distinctive. At the same time, the psychological processes whereby religious identity operates are shared by other identities, including how new information is incorporated into that identity and how existing identity content is altered (Breakwell, 1986).

| Religious identity and workplace diversity
Identity is core to diversity in the workplace reflecting fundamental social differences among people. Workplace diversity entails more than visible or surface-level diversity (e.g., age or ethnicity), but also the deep-level diversity associated with sexual orientation, class, or, indeed, religion (e.g., Ghumman, Ryan, & Park, 2016;Harris & Yancey, 2017).
Although some religious identities can be invisible to coworkers, others have visible signifiers, such as the wearing of a hijab, kippah, or turban by some Muslim women, Jewish men, and Sikh men, respectively. Visible signifiers became concerns in diversity policy during the mid-1980s with the changing composition of the workforce (Sauer, 2009), and continue to be important to diversity policy today (Bond & Haynes, 2014).
Current norms in workplace policy tend to focus on religious accommodation, such as allowance of prayer time and time off for religious observance (Atkinson, 2000;Cash, Gray, & Rood, 2000;Digh, 1998;Huang & Kleiner, 2001;Starcher, 2003), but may not necessarily address how religious and occupational identities interact.
The notion of authentic self is a key aspect of diversity at a deeper, more invisible level. It refers to the desire to express one's internal self through actions in the external world (Guignon, 2004). In the context of the religious self in the workplace, to be authentic employees must experience congruence between their internal values and external expressions (Roberts, 2013). Workplace behavior and practice can create challenges for the expression of an authentic self.
Consider, for example, that some police officers who are religious may see their work as furthering a religiously understood "common good." Within Christianity, forgiveness is a prominent theme in scripture and theology, alongside concepts of sin and mercy. Yet Christian officers typically act on behalf of the legal system and do not have the right to offer forgiveness on its behalf, although occasionally they may exercise mercy through discretion. That means that divergent identity demands may create internal conflict and tension that individuals may need to manage. To inform our understanding of religious identity in the workplace, we now review the relevant literature.

| Review questions
We seek to shed light on the dynamics of religious identity in the workplace. Two specific questions are the focus of our review:

| SR METHOD
Adhering to a structured, transparent protocol, SR methodology represents a comprehensive review method (Tranfield, Denyer, & Smart, 2003) that helps consolidate literature across fields (Rojon, McDowall, & Saunders, 2011). Using a series of search strings regarding identity, religion, occupation, compatibility, conflict, and health (Table 1) in 11 electronic academic databases (e.g., Business Source Complete, Web of Science, Sociological Abstracts, Medline, Cochrane Library), we identified sources to review. To be inclusive, we neither specified a start date nor delimited publication type. Publications needed to be relevant to one or more of our review questions, written in English, and available on or before March 2018. Searches resulted in 70,752 nonduplicated, potentially relevant documents. Most were peer-reviewed articles, with some non-peer-reviewed materials (e.g., reports and summaries) and books or chapters. We also included proceedings, papers in press, and dissertations. Other documents were considered if they were informed by empirical work (e.g., reviews and theory papers based on empirical studies).
All materials were reviewed in light of the criteria specified earlier and then screened for relevance, first by title and then by abstract. We included papers on the basis of concepts related to those specified in our review questions (e.g., "religiosity" as a proxy for "religious identity").
A subsequent full-text evaluation of the resultant 373 papers focused on the relevance and quality of evidence, following published SR methodology (Rojon et al., 2011). Full-text evaluation was completed by the first author; 20% of papers were also reviewed by two coauthors to check for evaluation consistency. The 125 remaining papers were cross-checked for relevance by three authors, resulting in 53 publications addressing at least one review question ( Figure 1). We extracted information from the final set of 53 using a standardized data extraction form (e.g., purpose, theoretical framework, method, contribution). These data were grouped by the relevant review question and then by their key findings and relevant theory (Popay et al., 2006). Table 2 describes the 53 publications included in our review, reporting their publication year, religion-related construct (e.g., religious identity, religiosity, identity work, etc.), religion(s) addressed (e.g., Muslim, Buddhist), sample (e.g., healthcare or business professionals), work behavior, and outcomes (e.g., prosocial behavior, care giving, stress).

| FINDINGS
Although some works did not address occupational identity specifically, all focused on the phenomena associated with religious identity in the workplace. Our findings are summarized in relation to our review questions (Figure 2).

| How do religious and occupational identities interact?
To answer Question 1a, we focused on the interaction of religious identity and the workplace. Three key features appear to influence how religious identities interact with an individual's work setting and occupation, and in doing so shape whether and how individuals express their religious identities at work: (a) the individual's personal preferences, (b) the opportunities the work role provides to express that identity, such as the support from the larger organization, and (c) the characteristics of the worker's specific religious belief system.

| Personal preferences
Individuals differ in their personal preferences regarding the integration of nonwork roles into the workplace (Ramarajan & Reid, 2013). These preferences are influenced by prior experiences, norms for religious expression, and the strength of religious identification. People for whom religious identity is salient tend to prefer to express that identity at work (Gebert et al., 2014). Individuals actually may choose an occupation because it aligns with their religious identity (Ramarajan & Reid, 2013), as in the case of service providers and patient caregivers (Pelechova, Wiscarson, & Tracy, 2012). Religious identity can be experienced as a strength that enhances empathy in difficult professional situations, as in the case of religious physicians who report fewer dilemmas and less stress in the context of terminal care than their less religious colleagues (Pawlikowski, Sak, & Marczewski, 2012). Such personal preferences have implications for career choice and perceived fit with the job and organization.

| Opportunity to enact religious identity
The opportunity to express religious identity in a work role affects whether and how a person does so (Ramarajan & Reid, 2013

| A religion's system of belief, norms, and values
The system of beliefs, norms, and values associated with a religious identity also contributes to its interaction with the workplace. Religions have strong meaning systems with cognitive, motivational, and affective components (Park, 2007). They are attached to specific norms, values, and behaviors that influence how an individual enacts a religious identity at work. Thus, the specific religion that individuals espouse can affect their ability and motivation to enact it at work (Al-Yousefi, 2012;Flanigan, 2009;Kutcher, Bragger, Rodriguez-Srednicki, & Masco, 2010). The emphasis on "tikkun olam" (healing or repairing the world) in Judaism (Schwarz, 2006) could motivate a Jew to engage in work that advances social justice or pursue opportunities for such action in the workplace, while an emphasis on "love one another" could motivate a Christian to display substantial empathy in counseling clients and patients (Morrison & Borgen, 2010). Similarly, the attitude of some conservative Christians toward sexual minorities may create adverse reactions to gay and lesbian clients (Harris & Yancey, 2017).
Together, these three features shape the degree of compatibility or congruence between religious identity and the workplace.
or more identities activated at the same time. In the context of religious identity in the workplace, we find that congruence reflects a continuum varying in its degree, ranging from the identity states of incongruence (e.g., in conflict or tension) to coexistence (e.g., as separate with neither synergy nor conflict) to high congruence (e.g., fit, compatible, or synergistic).  Swann, 1987). Particularly in the context of multiple identities, individuals are expected to seek continuity of self and at the same time to live up to the expectations others have of them. Thus negotiation involves both adjustment to and management of the expectations of others. We distinguish this multiple identity negotiation from the concept of "identity work," which usually pertains to a single identity or role (Ibarra & Barbulescu, 2010). We report our findings regarding Question 1b for each identity state.
The state of identity incongruence is associated with identity conflict when two (or more) identities are in conflict, mutually exclusive, or incompatible. Our review found considerable evidence of conflicts that engender identity incongruence (e.g., Chan-Serafin et al., 2013;Graber & Johnson, 2001;James, 2007;Sav et al., 2014). These conflicts arise when workplace expectations make religious expression difficult particularly due to competing demands from an occupation and a religion. Graber and Johnson (2001) suggest organizational avoidance of religion perpetuates the belief that religious and occupational identities are misaligned, consistent with the notion that religion and spirituality (Hill et al., 2000) are "irrational" or "emotional" with no place in a modern organization. Carlisle (2016) reports that although participants recognized the potential value of religion for mental health service users, its translation into practice was marked by controversy and ambivalence, suggesting difficulties in developing sufficient psychological safety (c.f., Nembhard & Edmondson, 2006) to permit the comfortable expression of religious identity at work. The literature reports two kinds of conflicts associated with identity incongruence: intraindividual and interindividual, which we now describe more specifically.
Internal or intraindividual conflict is a common focus in research on religious identity and refers to "conflicts in values beliefs, norms, and expectations held by a single individual" (Horton et al., 2014, p. 3 Interindividual conflict is the subject of several studies on religious identity at work. Employees with strong religious identities experience conflict with their colleagues and clients or customers when workplace requirements constrain an identity's expression or when employees believe their own religious identity is not respected (Flanigan, 2009;Gebert et al., 2014;Ghumman et al., 2016;Lucchetti et al., 2016). The importance of interindividual dynamics accords with Reddy and Gleibs' (2019) observation that identity negotiation is enacted in relation to a specific audience (e.g., other organizational/occupational members or clients/customers) and that any tension or synergy need not be solely within a person, but can exist among individuals as well (W. B. Swann, 1987). In the face of tensions between religious and occupational identities, Koerner (2014) posited that acts of workplace courage can be viewed as "episodes of identification" where identity tensions are reconciled through sense-making processes that lead to enhanced perceptions of integrity, pride, joy, relief, and confidence.
Religious differences among employees can lead to subgroup vigilance regarding the quality of their treatment, reflecting interindividual level phenomena (Horton et al., 2014). However, we find little study of intergroup conflict at work in the context of religious identity.
Nonetheless, Cintas et al. (2013) observe religious and occupational identities can increase tensions at work if a specific religious group is seen as favored, creating feelings of unfairness.
High identity congruence occurs when synergy exists between one's religious and occupational identity. It exists when the values between them align. High congruence can lead to the identity management strategy of enhancement (when multiple identities enrich or facilitate one another) by promoting self-continuity (Dutton, Dukerich, & Harquail, 1994) where one identity can enrich others (Greenhaus & Powell, 2006;Rothbard, 2001

| What are the implications of conflict and compatibility between religious and occupational identities for the well-being of employees and organizations?
Question 2 seeks understanding of the consequences of differing degrees of compatibility or congruence between religious identity and the workplace. Our results link religious identity to a variety of workplace behavior and outcomes such as indicators of employee well-being.
We find multiple studies of the influence of religious identity on individuals' workplace decisions, particularly in the medical profession.
Physician religious identity affects how doctors perceive and attend to end-of-life care: very religious physicians are less likely to withdraw life-sustaining treatment or agree to euthanasia than less religious physicians (Wenger & Carmel, 2004). It also influences how physicians communicate with the parents of dying children (Bateman & Clair, 2015). Likewise, religious physicians are more likely to support the hopes of their patients, and are better able to deal with the grief associated with caring for dying children and their families compared to nonreligious physicians (Martis & Westhues, 2015). Degree of congruence in religious identity expression also has organizational consequences. As noted, strong religious identity can increase tensions between employees and with clients in service organizations (e.g., Harris and Yancey (2017) and between different religious (or nonreligious) groups at work (Cintas et al., 2013). On the other hand, multiple identity enhancement brings interpersonal and organizational benefits largely through increased prosocial behavior (Ramarajan, Berger, & Greenspan, 2017). Similarly, Kutcher et al. (2010) found religious expression at work can promote citizenship behavior. Moreover, among mental health professionals, congruence between religious identity and the workplace contributes to better patient care through positive attitudes and greater empathy (Pelechova et al., 2012). Flanigan (2009) found staff from faith-based organizations perceived benefits such as the ability to promote reconciliation through service provision, credibility in the community, individualized and compassionate service, and committed and motivated workers. In their review of research on spirituality and religion in the workplace, Benefiel, Fry, & Geigle, (2014) suggest a link between religion and a firm's performance (e.g., in terms of productivity, sales growth, and work-unit performance) as well as employee work attitudes (e.g., job satisfaction, commitment, altruism, loyalty, and attachment). Narrative reviews suggest religious identification increases worker well-being (Greenfield, Vaillant, & Marks, 2009;Ysseldyk et al., 2010) while involvement in religious activities increases mental, emotional, relational, and physical fitness (Koyn, 2015).
Key variables affecting how religious employees negotiate role demands include the value-fit between religious identity and jobrelated concerns (e.g., empathy with clients, clinical decision-making: Morrison & Borgen, 2010), the organization's culture, policies, and practices, as well as role expectations (Graber & Johnson, 2001;Kutcher et al., 2010) along with an employee's formal status and the nature of the employment relationship (Haines & Saba, 2012). Kutcher et al. (2010) found religious practice at work-in particular the freedom to express religious identity-was negatively related to work-related stress and burnout and positively related to job satisfaction, organizational citizenship behavior, and commitment. They conclude that where religious identity is given room for expression, and thus can be either highly congruent or coexistent with an occupational identity, positive behaviors and job attitudes are likely; where expression is not permitted, outcomes are more negative.
The nature of the organization's workforce is likely to contribute to the importance of supports for religious expression in terms of engendering well-being and other positive consequences. Organizations that encourage such expression are likely to positively affect employees' job attitudes, performance, and retention (Cabel, Gino, & Staats, 2013). We note religious involvement has been found to have a positive effect on the well-being of African American employees, helping them cope with stressful job situations (Henderson, 2016), a feature found in other populations too (e.g., Sterner & Jackson-Cherry, 2015). This finding is echoed in  (Cintas et al., 2013;Kutcher et al., 2010;Sav et al., 2014;Terkamo-Moisio et al., 2017). Such tensions can influence the expression of an authentic self at work (Gates, 2001), well-being (Haines & Saba, 2012), and the quality of workplace relationships (Morrison & Borgen, 2010;Pelechova et al., 2012;Wenger & Carmel, 2004).
Further, we find evidence that links the expression of religious identity to employee well-being and role performance. Positive effects in the treatment of clients and patients are evident when the identity expression is highly congruent. Moreover, these consequences appear to be moderated by workplace norms regarding religiously-motivated behavior and client preferences. A key finding of our SR is that religious identity and the values and practices associated with it (e.g., compassion, helping) tend to have benefits at work particularly in specific occupations (e.g., mental and physical health professions- Pawlikowski et al., 2012;Pelechova et al., 2012;Seale, 2010) by enhancing emotional labor and relational elements in dealing with clients or patients.

| DISCUSSION
Although religious identity has been largely neglected in diversity management research (Tracey, 2012), respond to the degree of congruence between religious identity and occupational requirements and responsibilities, which in turn has consequences for how individuals manage their identities in the workplace. We summarize these findings in Figure 2.

| Agenda for future research
This SR points to the potential benefits of promoting the integration of religious and occupational identities at work, particularly in terms of work attitudes, well-being, and performance. We conclude that employees tend to experience their religious identity as congruent when occupational and religious beliefs, and related values, norms, and/or behavioral requirements overlap (i.e., an individual-level interaction). Importantly, HR has a critical role in balancing the religious accommodation and job demands as well as promoting inclusive organization. Further, employees tend to experience high congruence when workplace requirements, policies, and relationships support the expression of religious identity (i.e., a cross-level interaction). Nonetheless, significant research gaps remain and thus we identify three key considerations for future research.

| Careful conceptualization of religious identity
Religious identity was not consistently defined or operationalized in the studies we reviewed. The related concepts of religiosity, spirituality, and religious identity are often used interchangeably, but differ as described in our introduction. For example, Greenfield et al.'s (2009) large-scale survey of Americans found that spirituality was positively related to psychological well-being, with "spirituality" defined as an individual's sense of connection with the transcendent, integration of self, and feelings of awe, gratitude, compassion, and forgiveness. They contrasted this with "religiosity," the individual's endorsement of a religion's doctrines and values, which was unrelated to well-being. We note that both spirituality and religiosity differ from religious identity, our focus, which emphasizes the dynamics associated with a social identity involving membership in a specific religious group. As such spirituality and religiosity are likely to yield somewhat different effects from religious identity, differences which merit further study.
As outlined earlier, we propose future management scholarship should employ the concept of religious identity as a social identity anchored in a system of beliefs and religious affiliation, as proposed by Ysseldyk et al. (2010). Thus conceived, the concept of religious identity is firmly embedded in a theoretical account explaining the psychological utility of a specific group membership (Correll & Park, 2005;Tajfel & Turner, 1979). Hence, a social identity perspective posits that identification with one's group motivates individuals to distinguish that group from others to preserve positive self-esteem and self-regard. It also guides acceptance of relevant norms and the actual behavior associated with a social identity (Turner et al., 1987). Religious identity, with its link to a specific group membership, can be especially central to self-concept, by virtue of its salience and availability. As we described earlier, religious identity is distinct from other forms of identity in that religions reflect a commonly held belief system involving self-transcendence, the sacred, and a specific moral authority. Identification with one's religious group may provide the person with a sense of stability and "solid ground" (Kinnvall, 2004).

| Adopting a multilevel approach
The reviewed literature generally addresses individual-level phenomena and pays less attention to interpersonal relations and intergroup dynamics. Scholars nonetheless increasingly recognize that context (e.g., organizational and societal) shapes workplace attitudes and behavior (e.g., Griffin, 2007;Meneghel, Borgogni, Miraglia, Salanova, & Martínez, 2016). Thus, research on religious identity in the workplace needs to broaden its reach to address more interpersonal (dyadic or within-group) and intergroup and organization-level phenomena, such as cross-level interactions. A multilevel lens draws attention to the richness of social behavior and its many-tiered consequences (Hitt, Beamish, Jackson, & Mathieu, 2007;Rousseau, 1985). In this regard, research is needed on how diversity policy and related norms influence relationships among members with different religious (or nonreligious) identities and subsequent individual, work group, and organizational effects. We note that Zolotoy, O'Sullivan, and Martin (2018) have found that religion-based social norms affect the motivational impact of using equity-based incentives. We infer that religion can play a heretofore unrecognized role in differential responses at the individual and group-level to organizational practices and policies.
The degree of identity congruence has implications for interpersonal and intergroup relations (e.g., coworkers and clients or customers). Dutton et al. (2010) argued the more an individual's overall identity structure contains complex facets (as in the case of many religious and occupational identities), the more that individual has the capacity to form positive relationships with diverse others at work. One way of dealing with contradictions between personal identities and organizational practice is to engage in identity negotiation in order to temporarily resolve tensions when identities are incongruent (Giorgi & Palmisano, 2017). Yet, the ongoing experience of identity conflict might ultimately prompt resolution via institutional or individual change (Giorgi & Palmisano, 2017). However, identity states (high congruence, coexistence, or incongruence) affect not only employees as individuals but also their relationships at work. Compared to the effects of identity expression and congruence on individuals, less is known about their effects on intergroup and organizational outcomes.
We posit that, under the right circumstances, identity negotiation can reduce identity conflicts both within the individual and in relation to others, as in the case where the individual wishes to express a religious identity and the organization is supportive. As Ashforth (2016) noted, the multifaceted nature of identity can yield more nuanced role enactment than is currently recognized. The psychological research we reviewed in the introduction characterizes the various cognitive and emotional processes associated with identity negotiation and intergroup relations. The social composition of work groups and organizations, and their larger cultural context, are likely to influence these processes (Hitt et al., 2007). Organizational factors such as culture, policies, and leadership can aid or undermine the negotiation process.
Our SR highlights the multilayered nature of this undertaking. Yet, seeking to enable high congruence through the integration of religious and occupational identities may challenge the common representation of religion as a private matter (Parsons, 1966;Taylor, 2007;Tracey, 2012). Concern and resistance may be encountered from coworkers, clients, or the organization broadly. In order to engage effectively with such issues, it is important to be mindful of how religion and religious identity relate to workplace behavior, particularly for organizations with a diverse workforce.

| Faultlines related to religious identity in the workplace
Faultlines are dividing lines that can split a group into subgroups based on one or more attributes (Lau & Murnighan, 1998), such as demographics, identity, interests, or knowledge. Although potential faultlines in organization-based groups can take myriad forms, the critical issue is whether the faultline is dormant or activated. Faultlines may be activated by disputes over influence and entitlements, and thus conflicts regarding religious expression may become a source of faultline activation, undermining quality of interpersonal relations as well as employee satisfaction and group performance (Jehn & Bezrukova, 2010). However, as yet no research has been conducted into faultline activation processes in the context of religious identity at work. We note, however, that with respect to other faultlines, a supportive diversity climate has been found to mitigate their negative consequences and generate loyalty to the larger organization (Chung et al., 2015), just as team identification has been found to mitigate the effects of faultline activation and enhance team member satisfaction (Jehn & Bezrukova, 2010). Such findings are promising for insight into the interpersonal dynamics of religious identity at work and for promoting effective diversity management. We strongly advise that a faultline perspective be brought to bear in explicating the interpersonal and group dynamics associated with religious identity.
Joint consideration of these three areas raises critical questions for future study. First, how do the intragroup and intergroup dynamics engendered by faultlines differ when religious identity is activated as opposed to other forms of identity in the workplace? Given the salience of religious identity, we posit that its activation engenders more adverse interpersonal tensions than would differences in spirituality or other within-group differences with lower salience. On the other hand, organizations with supports for workplace tolerance and religious expression are expected to induce higher member loyalty and in doing so avoid faultline activation. That leads to our second critical question for future study: What forms of workplace climate and related HR policies and practices serve to activate or downplay faultlines derived from religious identity? Diversity practices focused on enhancing staff development and professional success broadly are likely to have very different consequences compared to those seen as benefiting just a few (Rousseau, 1995). The nature and implementation of such practices can vary in terms of the workplace fairness they generate (e.g., Nishii, 2013), and the effect of justice perceptions on diminishing faultline activation (e.g., Antino, Rico, & Thatcher, 2018).

| Limitations of our SR and the broader literature
We must acknowledge limitations in the findings of our SR. First, despite a rigorous search process, we may have omitted relevant publications due to the specific keyword searches we applied. For example, the use of "health" as one of our search terms (related to the "well-being" element of our review questions) may have screened out some publications. Second, we included only work in English. Third, our analysis did not include broader notions of spirituality as these fell outside the scope of our review.

| IMPLICATIONS FOR PRACTICE
Religious identity is an inherent facet of workforce diversity, one that organizations and managers should be prepared to address. Our review finds fairly strong evidence that religious identity tends to be a prejudice (Anker & Afdal, 2018) while respect means to take an active stand with respect to interpersonal treatment (Feinberg, 1973). Our findings suggest that organizational practices can contribute to each, an important consequence of diversity management since conflicts between religious and occupational identities take a toll on both individual well-being and contributions at work (W. Swann et al., 2009). At the same time, insufficient effort to create a tolerant and psychologically safe community for all employees can activate faultlines such as those based on religion. Attempts to exclude religious identity from the workplace are likely to be an unsustainable approach to diversity management (Hicks, 2002). Even in contexts where religion has been a source of social strife (e.g., see Dickson & Hargie, 2006), responses to religious identity in the workplace have centered on strategies for the optimal management rather than exclusion of religious identity and diversity (e.g., see Equality Commission for Northern Ireland, 2016). In our advice for practice, we first highlight how our SR can inform the successful integration of religious identity at work and then describe ways to address potential conflicts and concerns.

| Adopting a balanced approach informed by law
In Respectful pluralism is grounded in a climate of psychological safety in an organization (Nembhard & Edmondson, 2006). Such a climate is characterized by a shared commitment to mutual respect and individual dignity (Roberge & van Dick, 2010). For individuals to feel psychologically safe means feeling free to express elements of themselves without fear of adverse implications. Safety is promoted by activities that support staff in discussing their beliefs (Pelechova et al., 2012), including how religious identity relates to work expectations, behavior, and relationships, as well as by training that promotes links between religious and occupational identities (Sav et al., 2014 necessitates attention to the concerns and interests of the organization and its mission as well, such as respectful interactions with the public. We note that well-implemented organizational missions tend to become internalized as part of the personal values of members, consistent with the notion of an ideological psychological contract in employment (e.g., Krause & Moore, 2017). We suggest that HR gather information regarding the kinds of client services and encounters that raise potential value conflicts and the ways that employees currently respond to these conflicts. Such conflicts provide the basis for discussion, feedback, and redesign of work processes. In instances where conflicts are not readily resolved, procedures can be developed through staff input and experimentation to ensure that the organization's responsibilities to the public are fulfilled should a religious employee raise an objection. Moreover, alerting management or peers to a potential objection can provide a basis for creating a solution that complies with personal beliefs, recognizing of course that not all requests for accommodation may be met.
The key idea is to get the issues of value conflict and congruence into the collective organizational conversation. Organizational members with diverse backgrounds are important sources of insight into how to address value conflicts in a mission-appropriate fashion. Periodic attention to such events and potential conflicts provides an opportunity to reflect on ways in which personal values can be expressed while fulfilling the organization's mission. Consider the employer who successfully accommodates employees wishing to pray at work by establishing a reflection room available to all employees.
Or, consider company policy that requires a pharmacist who refuses to give abortion-related drugs to turn the prescription over to another

| CONCLUSION
In closing, the findings of our review offer a dynamic perspective on religious identity in the workplace, highlighting the important connections religious identity has with work behavior and organizational outcomes. They point to new opportunities for supporting religious identity in the workplace and reducing potential conflicts. Much of the previous research on multiple identities has focused on conflict.
However, our review indicates that the degree of congruence between employees' religious identity and their understanding of themselves and their work roles and responsibilities can vary considerably. It suggests high congruence is both possible and even common in certain kinds of settings. Importantly, we find that religious identity is often a net benefit in contemporary organizations and much can be done to enhance this benefit while reducing tension and conflict. Of critical importance is the psychological safety the organization provides to all its members, a key factor in workforce well-being and effectiveness. Complementarity between religious and occupational identities can become the norm, tapping the benefits of each. We conclude with the words of Sheryl Sandberg (2012): "Bring your whole self to work. I don't believe we have a professional self Monday through Friday and a real self the rest of the time. It is all professional and it is all personal."

ACKNOWLEDGEMENTS
Special thanks to associate editor Yehuda Baruch for his helpful guidance throughout the revise and resubmit process. We also thank the three anonymous reviewers who provided constructive feedback and insightful comments that enabled us to improve our work. Appreciation to Gary Roberts and Samuel Aryee for their comments on earlier drafts of this article and to our systematic review advisory group members for their advice at the inception of the systematic review.
We wish to express our sincere thanks to Mary Jo Dively and Dan