Professional identity research in the health professions—a scoping review

Professional identity impacts the workforce at personal, interpersonal and profession levels however there is a lack of reviews of professional identity research across practising health professionals. To summarise professional identity research in the health professions literature and explore how professional identity is described a scoping review was conducted by searching Medline, Psycinfo, Embase, Scopus, CINAHL, and Business Source Complete using “professional identity” and related terms for 32 health professions. Empirical studies of professional identity in post-registration health professionals were examined with health profession, career stage, background to research, theoretical underpinnings and constructs of professional identity being extracted, charted and analysed using content analysis where relevant. From 9941 studies, 160 studies across 17 health professions were identified, with nursing and medicine most common. Twenty studies focussed on professional identity in the five years post-entry to the workforce and 56 studies did not state career stage. The most common background for the research was the impact of political, social and healthcare reforms and advances. Thirty five percent of studies (n = 57) stated the use of a theory or framework of identity, the most common being classified as social theories. Individual constructs of professional identity across the research were categorised into five themes—The Lived Experience of Professional Identity; The World Around Me; Belonging; Me; and Learning and Qualifications. Descriptions of professional identity are broad, varied, rich and multi-layered however the literature is under theorised with current theories potentially inadequate to capture its complexity and make meaningful contributions to the allied health professions.


Introduction
Professional identity impacts the workforce at personal, interpersonal and profession levels, yet our understanding of this phenomenon is still developing. In the health professions, literature reviews of professional identity involve single professions, are focussed on students or involve multidisciplinary teams and do not address the range of health professions or their specific issues post registration (Best & Williams, 2019;Jebril, 2008;Maile et al., 2019;Sarraf-Yazdi et al., 2021;Snell et al., 2020;Volpe et al., 2019;Woods et al., 2016;Wyatt et al., 2021a). There has been no synthesis of professional identity research for practising health professionals or attempts to use the different theoretical perspectives described in the literature to deepen our understanding of professional identity and its impact on the health workforce.
The history of identity research is long and complex with many different approaches employed to understand this phenomenon. Identity research can be overwhelming and confusing (Korthagen, 2004)-the term identity has been used by researchers from a range of different fields and a range of paradigms and language, and has been conceptualised from multiple perspectives with connected and overlapping concepts Grootenboer et al., 2006;Kasperiuniene & Zydziunaite, 2019). It is acknowledged that the various subdivisions and categories within the research are somewhat arbitrary, and the different terms and categories used in professional identity research do not refer to orderly, agreed on, and internally consistent sets of ideas, rather their meaning is dependent on the vantage point of the researcher. Despite this, providing a framework to classify identity research is useful to begin to scope the literature in this area. Grootenboer et al. (2006) suggest these approaches fall into three categories based on theoretical underpinnings of the research: (i) individual-psychological/developmental; (ii) sociocultural; and (iii) poststructural perspectives.
Individual approaches to identity research originated in Erikson's psychoanalytic theory of ego identity (Marcia, 1993) and focus primarily on psychological and/ or developmental perspectives of the individual. Identity is conceptualised as being located as internal to the individual with identities being regarded as self-determined in response to life experiences (Kroger & Marcia, 2011). For example, in the health professions individual professional identity has been described as an actualisation of one's morals, values and beliefs (Fagermoen, 1995(Fagermoen, , 1997Gomaa, 1999; giving meaning to one's self and one's professional life (Fagermoen, 1995).
Social approaches to identity in contrast focus on the interaction of the individual with their social surroundings, both in relationships with individuals (Chen et al., 2011) and groups (Spears, 2011) and with culture in general (Serpe & Stryker, 2011). Tajfel (1979) first conceptualised social identity as being located both internal and external to the individual and developed through social interactions and practices. Social aspects of identity in relation to the group, referred to as collective professional identity, are said to guide professional behaviours and practices through professionalisation (Fagermoen, 1997;Niemi & Paasivaara, 2007). This internalisation of beliefs, values, and behaviours of the profession (Cruess et al., 2015;Jarvis-Selinger et al., 2012) dictates the way in which members of the professional group behave (Abrams & Hogg, 2004;Beddoe, 2011Hogg et al., 1995;Smith & Terry, 2003;Terry & Hogg, 1996). Identification with the professional group thus contributes to the development of competent and confident health professionals Feen-Calligan, 2012;Findlow, 2012;Ohlen & Segesten, 1998; influencing the way in which individual professional identity develops and professional practice is enacted (Slay & Smith, 2011).
Poststructural approaches challenge the idea of identity being either an individual or social phenomenon (Halualani, 2017;Zembylas, 2003). With the two key concepts of poststructural perspectives being discourse or 'language in use' (Cameron & Panovic, 2014) and the subject or self (Foucault, 1982), poststructuralism theorises the self and the social world as socially constructed through discourse (Foucault, 1981). Poststructural approaches to identity interrogate discourse and knowledge fields from which questions of identity are posed and rather than being individual or social posit that identity is located within a broader context embedded in power relations, ideology, and culture and dependent on power and agency (Zembylas, 2003). This broader context includes that of the research as well as the researcher (Harding, 1991). Understanding that whoever defines the problem has a powerful role in shaping the worldview that results from the research (Harding, 1991), interrogating the place from which questions of identity are posed can add to understandings of the social and historical context of practices and discourses in the health professions (Bhabha, 1987). Poststructural approaches attempt to address these underlying assumptions, paradigms and biases that impact the research process at every stage, from concepts and hypotheses selected, to research design, to collection and interpretation of data (Harding, 1991).
Criticism of professional identity research in the health professions has begun to emerge with concerns that critical aspects of professional identity and their associated power relations have not been adequately considered (Tsouroufli et al., 2011;Volpe et al., 2019;Wyatt et al., 2021a;Wyatt et al., 2020;Sarraf-Yazdi et al., 2021). Critical approaches to identity compel us to consider not only broader contexts such as discourse and knowledge fields and the positionality of the researcher and the research but to also consider the intersectionality of history, culture, race, socioeconomic status and gender to arrive at a more nuanced and contextual understanding of identity (Halualani, 2017). Consideration and understanding of critical perspectives of professional identity is essential for the well-being, resilience and advancement of health professionals and the health professions. For example, it has been argued that identities based on group membership are utilised for implementing forms of control through a standardised identity (Jemielniak, 2008), for the maintenance of dominant social groups (Tsouroufli et al., 2011;Wyatt et al., 2021a) and for the production and reproduction of dominant ideologies . This likely contributes to issues with reconciling personal and professional identities, an ongoing task of professionalization (Baldwin et al., 2017;Moorhead et al., 2019;Sharpless et al., 2015;Volpe et al., 2019). For many professionals this is straightforward, however for those whose personal identities or beliefs are at variance with aspects of their professional identity, for example, dominant social groups, dominant professional paradigms or expectations of professional roles, consolidation of professional identity may be problematic (Costello, 2005;Monrouxe, 2010;Volpe et al., 2019;Wyatt et al., 2020Wyatt et al., , 2021aWyatt et al., , 2021b. This can be particularly so as public and social policy as well as public perception shape identity as much as the self-definition of the profession and the professional (Landman & Wootton, 2007). Considering the impact of current challenges in healthcare provision and changes to the way in which health care is delivered (Duckett, 2005;Green et al., 2001;Health Professions Council of Australia, 2005;Sturmberg et al., 2018;Swerissen et al., 2018) understanding individual and collective professional identities has never been more important as inability to reconcile personal and professional identity can contribute to identity dissonance and impact personal and professional health and wellbeing (Costello, 2005;Monrouxe, 2010). To address recent criticism of the professional identity literature and to elucidate different perspectives of professional identity it is important to interrogate why professional identity among health professions has been studied, how, by whom and in whose interest. Synthesising this evidence will provide a more contextual understanding of the body of literature, why it has been studied and in whose interest, which will identify gaps as well as contribute to an appreciation of perspectives that may be impacting our understanding of professional identity and its impact on health workforces. As such we set out to explore the current literature on professional identity across the health professions using a scoping review.
Scoping reviews are effective tools for understanding the extent, distribution and basis of the literature when an area of research is complex or has not been reviewed comprehensively (Arksey & O'Malley, 2005;Mays et al., 2001). Scoping reviews allow for the mapping of theoretical frameworks, concepts and methodologies underpinning an area of research as well as the main sources and types of evidence available (Arksey & O'Malley, 2005;Mays et al., 2001). Categories described by Grootenboer et al. (2006) were used to address questions of theories, frameworks and constructs of profession identity in this review of the health professions literature. Taking into consideration criticisms of inadequate consideration of critical aspects of the research we expanded the category 'poststructural perspectives' to 'poststructural and critical perspectives', grouping together perspectives which interrogate or disrupt underlying assumptions of the research. This scoping review is not an effort to produce an accepted standard definition or agreed-upon theoretical perspective for professional identity which may perpetuate power structures. Instead through examining and unpacking how professional identity is discussed this scoping review will contribute to our understanding of professional identity across the health professions (Greenhalgh, 2021) and encourage stronger consideration of theoretical perspective, broader contexts and reflexivity in research. Rather than simply mapping the research, this systematic scoping review aims to interrogate the research into professional identity of practising health professionals more fully to include questions of "why" and "in whose interest?" This scoping literature review aims to explore the literature on professional identity, specifically in what disciplines and career stage the evidence is focussed, why the research was undertaken, what theory or framework was used to guide the research and what constructs are used to discuss professional identity. Supporting a more contextual understanding of the body of literature this scoping review will not only identify gaps in the literature and identity perspectives of professional identity that are important across the health professions it will also assist researchers in navigating the complexity of literature across multiple health professions guiding considered, relevant and meaningful approaches to professional identity research.

Methods
A scoping review, guided by the six-step methodology originally described by Arksey and O'Malley (2005) and expanded by Daudt et al. (2013) and Levac et al. (2010) with reporting guided by PRISMA-ScR (PRISMA extension for Scoping Reviews) (Tricco et al., 2018) was conducted.

Identifying the research question (step 1)
The scoping review addressed the following question: How is professional identity described across the health professions literature? Specifically: Q 1: Where is most of the literature on professional identity located-by profession and stage of career? Q 2: What is the background for research into professional identity in the health professions-why are questions of professional identity being asked? Q 3: Which theories of identity form the basis of professional identity research in the health professions literature? Q 4. In addition to theories of identity what constructs of identity of professional identity are found in the health professions literature?

Identifying relevant studies (step 2)
A broad range of sources were searched for literature including multiple electronic databases and hand-searching of reference lists. However, only peer-reviewed empirical studies, including systematic and scoping reviews, and higher degree by research theses were included. Due to the large, rich, complex and heterogenous volume of literature in this field grey literature, i.e., materials and research produced outside of the commercial or academic publishing and distribution channels, was not included in the review. Inclusion and exclusion criteria for the scoping review were developed prior to study selection. Inclusion criteria used in our scoping study related to: type of study; health profession (n = 32); career stage; terminology and focus of the paper. In line with scoping review guidelines (Arksey & O'Malley, 2005;Daudt et al., 2013;Levac et al., 2010) inclusion and exclusion criteria were refined post hoc as we became more familiar with the literature and the various issues which impacted our search (Table 1). All decisions about inclusion/exclusion criteria were reached by consensus between the three authors.

Literature search strategy
In conjunction with the Faculty Subject Librarian (see Acknowledgements) search parameters were formulated and Medline; Psycinfo; Embase; Scopus; CINAHL; Business Source Complete were searched on 5 April 2020 by MC. An example of search strategies used is described in "Appendix 1". Search syntax (e.g., field codes and proximity operators) were modified to suit the individual databases to support answering the research question.

Study selection (step 3)
Studies from the search of the six databases were downloaded into Endnote (X9) and exported to Covidence (© 2020 Melbourne, Australia) for screening and assessment. Duplicates were removed and remaining titles and abstracts were screened for eligibility against exclusion and inclusion criteria (Table 1). Eligible studies underwent full text screening using the same criteria. All screening was carried out in duplicate by the first author and one of the other authors. Authors were dietitians by profession, with two of the three being experienced researchers and educators in the field and the third an experienced clinician and researcher. Decisions about inclusion/exclusion for disputed studies were reached by consensus between the three researchers.
Hand searching of reference lists of final included studies did not reveal any further studies.

Data charting and analysis (step 4)
To comprehensively explore descriptions of professional identity in the health professions literature to address the research questions, key information from the included research studies such as author, year and title data and so on were imported from Covidence to directly pre-populate the charting table. Information was noted and charted in a uniform and systematic way using Microsoft Excel (Version 1808, 2019). All studies were sorted and counted with respect to study characteristics.
To answer research question 1 additional information was identified including profession and stage of career of the health professionals. To answer research question 2 the background to the research questions was identified and categorised using conventional content analysis (Hsieh & Shannon, 2005). This involved extraction of statements in each study regarding the purpose, background and/rationale of the research which were assigned preliminary codes by the first author. Using content analysis these codes were grouped into initial categories which were progressively and iteratively grouped into larger categories describing the background to the research or why questions of professional identity being asked. To answer research question 3 studies in which a theory of identity or professional identity was stated as being used (or in which a novel framework of identity was developed within the study) were identified and theories classified. As described above, research into identity and professional identity originates from a range of traditions and encompasses multiple and varied paradigms and broad classification of theory can help with conceptualisations of these theories and their relationships. Three broad categories of identity theory; individual, social, and poststructural and critical perspectives, described discussed in the Introduction were used to classify identity theories from the included studies. To further refine categorisation Narrative was included as an additional category as descriptions of narrative-identity in the literature span all three categories (Smith & Sparkes, 2008). A further category, Environmental, was devised to accommodate a novel perspective of identity in the health professions literature which emphasizes the influence of the physical environment on identity (Hauge, 2007). Where a study did not explicitly state a theory or develop an identity framework, the authors closely examined the text to in an attempt to infer categories of identity or professional identity used in the research.
To ensure the rigour of this part of the coding process, a small number of studies (n = 10) were randomly chosen for comparison coding early in the process by selecting every 15th study of an alphabetical list of studies included in the review. These studies were coded against final categories of identity frameworks by two of the other authors (CP and SA) and resulted in strong agreement between the three coders. In instances where no author could agree on the use of a theory this study was classified as having no overt theory or framework.
To answer question 4, individual constructs of professional identity described across all studies were identified and classified using conventional content analysis. (Hsieh & Shannon, 2005) Extracted data were assigned preliminary codes by the first author. These codes or categories were then grouped into initial categories which were progressively and iteratively grouped into larger categories. Categorisation and re-categorisation of the categories within themes as well as linkages between them were further elucidated and developed as coding progressed. To ensure the rigour of this part of the coding process, a small number of studies (n = 8) were randomly chosen for comparison coding early in the process. These studies were free-coded (i.e., did not use the codes already developed) by one of the other authors (CP) and resulted in strong agreement between the two coders. This process was repeated for extracted data on influences on identity. Constructs or themes of identity described within the professional identity literature were charted accordingly.

Results (step 5)
The search yielded 9,941 articles and after duplicates were removed 4,691 articles were screened by title and abstract for eligibility against the selection criteria. Three hundred and twenty papers were deemed appropriate for full text-screening with a final 160 studies deemed eligible for inclusion in this scoping review (Fig. 1). For a complete list of the 160 references included in the review see "Appendix 2".

Q 1: where is most of the literature on professional identity located-by profession and stage of career?
The largest number of studies were from the United States (48), United Kingdom (26) and Australia (21) with the majority of studies focusing on the disciplines of nursing (59) and medicine (38) ( Table 2). The remaining 63 studies included other specialities.
Fifty-five studies included health professionals at various stages of their careers. Twenty of the 104 studies where career stage was stated included health professionals within 1-5 years of registration and 14 studies looked at professionals 6-10 years post-registration.  Q 2: what is the background to the research into professional identity in the health professions?

Q 3: which theories of identity form the basis of professional identity research in the health professions literature?
The majority of studies (131 or 82%) utilised qualitative methods, with the remaining using quantitative (20 or 12%) and mixed methods (9 or 6%) ( Table 4). A wide variety of theoretical and methodological approaches were applied (Table 4). Constructionism and phenomenology were used in 25 and 16 studies respectively and 13 studies took a grounded theory approach. The remaining studies using symbolic interactionism (6), interpretivism (5), criticalism (4), constructionism with a critical perspective (3); and poststructuralism (2). One study each used feminism; standpoint feminism; poststructuralism/feminism; poststructuralism (Bourdieu); social realism; existential phenomenology; or multiple theories (Bourdieu/feminism/cultural theory). Seventy-nine studies (49%) made no comment on overall theoretical framework.

Stated theories and frameworks of identity by category
Stated theories and frameworks were identified in the following categories-individual, social, and poststructural and critical. Combinations of theories and theories developed through the research were also categorised. As described above, the categories narrative, spanning all three main categories (Smith & Sparkes, 2008), and environmental, accommodating a novel perspective of identity (Hauge, 2007), were included.

Inferred categories of theories and frameworks of identity
One hundred and three studies did not specifically state theories or frameworks of identity used in the research. Four broad categories of identity were inferred from a secondary analysis-individual, social, narrative, and poststructural and critical and perspectives. Seventy-three studies of 103 studies were classified as Social in three subcategories. Thirty studies were identified as being focussed on group membership in their investigation ( & Roberts, 2016;Lotan, 2019;. This included one study which in which societal expectations around gender was the focus of professional identity  and one study in which situated learning was identified as the focus . Narrative perspectives of professional identity were identified in 10 studies (Blomberg, 2016;Clandinin & Cave, 2008;Dahl & Clancy, 2015;de Meis et al., 2007;Dombeck, 2003;Fragkiadaki et al., 2019; and poststructural and critical perspectives in 6 studies Gent, 2017;McNamara, 2010;Ngai, 2007;O'Shea & McGrath, 2019). Individual perspectives were identified in three studies including psychological/developmental approaches theories (Branch, 2016;Chan et al., 2018) and learning impacting the individual (1) . Categories of identity frameworks were not able to be inferred and assigned in 11 (7%) of the studies.

Q4. In addition to theories of identity what constructs of professional identity are found in the health professions literature?
Five major themes containing 37 categories of constructs of professional identify were determined from the health professions literature (Table 5). Note that studies may contain multiple constructs of professional identity. Constructs of professional identity linked to references in the health professions literature are presented in "Appendix 3".
As previously discussed, constructs of professional identity were not discrete but rather intertwined, reciprocal and changing dependent on the individual and circumstances (Fig. 2).

The lived experience of professional identity
The Lived Experience of Professional Identity comprised three categories, Becoming from Performing, Knowing from Practising and Practising. Becoming from Performing was referred to in 83 or 52% of studies. This category reflects performative aspects of professional identity development with individuals described as learning to identify as health professionals through observation and role modelling which was consolidated through repetition, practice, feedback and validation, and a growing sense of confidence as a health professional. This was not always experienced in a positive way as "the inhibiting culture of nursing was perpetuated through socialisation processes" (Ogilvie, 2012) or lack of role models for novel roles impacted developing identity. Becoming from performing also contributed to the co-construction of professional identity through collaboration with other professionals within intra-professional and inter-professional communities of practice.
Knowing from practising, discussed in 56 studies (35%), describes health professionals' experience with patients, clients, communities and students over years of practice giving meaning to and shaping professional identities.
Knowing from practising included two subcategories-Witnessing the experiences of others through relationships (30) and Personal experiences impacting interactions with clients (7).
Practising was described as intrinsic to professional identity in 23 or 14% of studies and was identified as a locus of professional identity in the health professions. Clinical practice was also described as important in the development of leadership and management identity, giving meaning to leadership and a contributing to maintenance of professional collective identity. Three subcategories of Practicing were identified in the literature as impacting professional identity development-Philosophy of practice, Visibility of practice and Autonomy in practice.
Role was identified as an important component of professional identity across a number of themes and was referenced specifically in 86 or 54% of studies.

The world around me
Workplace was described as contributing to professional identity in 62 or 39% or studies. Workplace is described as influencing professional identity by dictating practice of health professionals, through perceived inadequacy of workplace conditions (resources, time, remuneration) and through changing role, changing work, changing work environment and changing practice. Workplace influences on professional identity described above capture influences of political, social and healthcare reforms and advances, however these influences were discussed specifically in 21 or 13% of studies. Professional hierarchies between professions and within professions was described as impacting professional identity in 44 studies. Between-profession power hierarchies described the medical profession at the top of the hierarchy with community midwifery and school nursing literature describing themselves as being low in the hierarchy of professions. Other hierarchies of health professions/specialties were described by academics and by complementary and alternative medicine practitioners who described themselves as professions on the periphery. Within-profession hierarchies were described in the literature in relation to seniority, further training, expanded practice, higher or different qualifications, type of work, place of work (e.g., private vs public), prototypical behaviour in relation to the profession and married vs unmarried female doctors. These dynamics of hierarchy between and within professions were also noted as being important with respect to validation of value and competence of professionals. Hierarchies were noted to exist within an organisational context.
Dominant paradigms and discourses of health and practice with its impact on professional identity described in 44 studies. The biomedical model of healthcare was the Knowledge claims was described as influencing professional identity development in 22 studies. This included the privileging of evidence-based knowledge over experience-based knowledge, and benchmarked, marketable and externally levied 'quality' criteria being valued over immeasurable dimensions of practice such as the relational and experiential aspects of healthcare.
The health professional-client relationship was also discussed in 14 studies as a component of professional identity underpinning identities such 'expert' and 'fixer'.
Societal expectations of the health professions, were also identified as influencing professional identity formation in 13 or 8% of studies.

Belonging
Group identification (The Group) as an important aspect of professional identity was identified in 52 or 33% of studies with group collective identity being seen as important in 15 studies. The profession in relation to other professions, was another aspect of collective professional identity in seven studies. "Thinking of oneself as a ….." and doing, being, becoming, belonging to a discipline were identified as important in nine and three studies respectively. Identification with the organisation (Organisational identity) was seen as an important aspect in professional identity in 12 studies.
Boundaries in the professions were identified as influencing professional identity in 75 papers and described in two ways-through Boundary Crossing and through Boundary Closure. Boundary Crossing was documented in 58 or 36% of studies impacting professional identity in relation to increasing experience (crossing from novice to expert), undertaking more training or qualifications, as well expanded or specialist practice. Transition from clinician roles were also documented as influences-from clinician to educator, from clinician to academic and from clinician to manager/leader. Changes in clinical professions or working in novel areas of practice were also identified as boundary crossing as were dual roles such as clinician-scientists and clinician-manager and working across multiple boundaries, all of which were identified as influencing professional identity. The creation or existence of boundary closure between professions or specialties to consolidate professional identity development was discussed in 17 studies.

Me
Self as a component of professional identity was discussed in 38 (24%) studies. Self reflected the foundations of personal identity such as personal characteristics, values, feelings, as well as personal life with strong interrelationships between self, personal and professional identities described. Social work and nursing describe their professions as being intrinsic to self. Another aspect of self relating to professional identity described in nine studies The stories I tell about myself and described/included the dominant stories professionals tell about themselves on the basis of their lived experience in the world. These stories, through a reflexive practice, were described as providing opportunities for identification and deconstruction of discourses at play in the narratives with which we construct our professional identity, facilitating professional growth and transformation.
Gender, Race and Culture, Age, and Socioeconomic Status were described in 18, 5, 2 and 1 study respectively in relation to professional identity. Self in relation to others was identified as a category within this theme in five studies with narratives of oneself being described as always being in relation to, and constituted by, 'other'-supervisors, colleagues, students and family. Relation to others was also described in conceptualisations of professional identity related to the caring aspects of nursing/nursing education interactions-including representing, advocating for and providing for others.
Tensions exist between the self and developing professional identity and professional identity construction is partially triggered by work-identity integrity violations. Self & Fit was described in a total of 54 or 34% of studies as being important in professional identity. For example, Self & Fit was described as impacting professional identity in relation to fit, or not, between self and work, role or practice expectations, as related to fit with members of the professional group as well as fit with the profession.

Learning and qualifications
Learning through the acquiring knowledge and skills was discussed in 39 or 24% of studies. Further learning and qualifications was described as important in the differentiation of self from others within the profession with lack of further training and learning opportunities described as hampering professional identity development. Qualifications or credentialing as enhancing professional capital or improving the status of the health professional was discussed in 16 or 10% of papers. Qualifications or credentialling as shaping or controlling the profession were discussed as an influence on professional identity in 10 or 6% or studies.

Discussion
This scoping review sought to explore and interrogate the literature on professional identity for practising health professionals in order to understand on what disciplines and career stage the evidence is focussed, why the research was undertaken, which theory or framework was used to guide the research and what constructs are used to discuss professional identity. The findings provide insight into professional identity across 17 health professions of 32 investigated. Overall, the majority of studies were in nursing and medicine early in careers with the allied health professions poorly represented. Novel to this review, we identified the role of learning and qualifications as contributing to professional identity through increased knowledge and skills and social capital of the profession. Despite the number of studies and the demonstration of commonalities across the professions, this review demonstrates gaps in the research, both in the number of health professions that are represented in the literature as well as issues with theoretical perspectives and critical aspects of the research. Highlighted as well is the imperative for researcher reflexivity including an interrogation of how the agenda for the research into professional identity is set. Future research must further refine theoretical frameworks to develop questions and guide data collection and its analysis (Merriam & Tisdell, 2015). While there is promising new literature emerging Hammond et al., 2016;Scanlan & Hazelton, 2019; there is a need for further research that explores professional identity in post-registration allied health professionals. However, these findings provide guidance for health workforces, as individuals and collective identities, to successfully negotiate the constantly changing face of healthcare.
Our review scoped the rationale for research into professional identity, addressing the question of 'why' in professional identity research. This synthesis has developed a deeper understanding of the broader contexts and underlying perspectives, assumptions and biases of the research and the researchers. This not only contributes to a more nuanced and critical understanding of the limitations of the literature but also contributes to an understanding of conceptualisations of professional identity across the health professions. Interrogating the rationale for the research also calls to attention to the range of issues that are significant to the health professions and their professional identity, for example the impact of role transition or organisational change on professional identity or links between knowledge, credentials and professional identity. This scoping review has identified that professional identity research in the health professions is largely conducted to explore the impact of political, social and healthcare reforms and advances and to support the development of professional identity. This understanding can guide future research, professional development and education that is pertinent to the health professions including recruitment and retention of workforce, teamwork, progression to academia and leadership.
Highlighting the theoretical framing of professional identity research in this review further contributes to the understanding of the way in which professional identity is understood and discussed in the health professions literature. Our review identified that only 35% of research into professional identity explicitly states a framework or theory of identity. This may reflect a lack of coherence around important theoretical considerations underpinning much of the research and should caution the reader in interpretation of the research. Drilling down further into discussions of professional identity five categories of constructs of professional identity were identified across a broad range of health professions. As well as reflecting the broad categories of individual, social, narrative and poststructural and critical theories of identity, these multiple categories with their multiple subcategories reflect the multi-faceted and nuanced nature of professional identity and provide broad and rich insight into professional identity across the health professions. Taking into account the breadth of these aspects of professional identity will be useful for informing future professional identity research that is relevant to the health professions and further highlights that the arbitrary frameworks must be used with caution with a recognition of the complexity and depth of concepts comprising each category.
Our scoping review reinforces themes identified in previous reviews on professional identity in interprofessional teams and in studies which have included students. Themes of self, the impact of relationships with clients and other health professionals, as well as clinical experience and practice were identified as important influences on the professional identity in this review and others (Best & Williams, 2019;Volpe et al., 2019). As the research into professional identity in the health professions is important it is imbued with power (Zembylas, 2003) and this is reflected in the findings which describe hierarchies, dominant paradigms, contested knowledge, and social expectations. This scoping review also describes the role of hierarchies, autonomy and role enactment in professional identity and affirms existing evidence (Best & Williams, 2019;Volpe et al., 2019). The scoping review also highlights the limited exploration of race and indigeneity, socioeconomic status and gender in professional identity research which has been previously raised as a much needed area of professional identity research in health professions (Sarraf-Yazdi et al., 2021;Tsouroufli et al., 2011;Volpe et al., 2019;Wyatt et al., 2020Wyatt et al., , 2021aWyatt et al., , 2021b.

Limitations
Due to the small number of studies within most health professions in this scoping review it was not possible to sort theories and constructs of professional identity by profession and thus to identify if aspects of professional identity were more important to some professions than others. In addition, we recognise that categorisation of the theories used may not fully reflect the complex and interrelated nature of aspects of professional identity. Many studies included interwoven aspects to the research, often with one category of identity within another. It was at times difficult to differentiate between aspects of the social such as the group and group-defining behaviours and role with its expectations. For example, "what it means to be and act like a nurse" could be potentially interpreted as a Social Identity Approach (the group) or an Identity Approach (role).

Conclusion
This scoping review makes an important contribution to the literature by comprehensively examining the rationale and theoretical underpinnings of professional identity research across the health professions as well as exploring the multi-faceted and nuanced nature of professional identity. Professional identity research is under-represented in many health professions and is poorly theorised limiting the cohesion of research across a broad range of health profession. Critical perspectives of professional identity in the health professions literature is lacking, particularly with respects to race and indigeneity, socioeconomic status and gender. Addressing these limitations and taking the broad nature of professional identity into consideration will impact the articulation of meaningful questions and theoretical frameworks for future research. psychologist* OR "psychology graduate*" OR "psychology student*" OR doctor* OR medicine OR "medical student*" OR physician* OR nurs* OR midwif* OR "allied health" OR dieti?ian* OR dietetic* OR physiotherapist* OR "physical therapist*" OR "occupational therap*" OR "speech therap*" OR "speech patholog*" OR podiatr* OR "social work*" OR pharmac* OR paramed* OR dent* OR audiolog* OR osteopath* OR "exercise physiolog*" OR orthot* OR prosthet* OR optometr* OR orthopt* OR "rehabilitation counsel*" OR "music therap*" OR "art therap*" OR radiograph* OR "radiation therap*" OR "imaging technolog*" OR "nuclear medicine" OR "nuclear medicine technolog*" OR ultrasonograph* OR "perfusion techn*" OR "genetic counsel*" OR chiroprac* OR "Chinese medicine pract*" OR naturopath*  Roberts, C. (2016). The Heroic and the Villainous: a qualitative study characterising the role models that shaped senior doctors' professional identity. The stories I tell about myself Ngai (2007), , Clandinin and Cave (2008), , , Branch and Frankel (2016) Ogilvie (2012) are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/.