Mainstreaming the alternative format thesis in UK higher education: a systematic narrative review of institutional policies

ABSTRACT The alternative format PhD, in which doctoral candidates produce a thesis composed of a series of peer reviewed publications, is growing in popularity internationally. However, across the HE (HE) system in the United Kingdom (UK), universities have been slower to adopt the alterative thesis format. This paper presents a systematic narrative review to understand the development of institutional-level policies pertaining to the alternative thesis format across UK HE institutions (n = 135), identifying best practice and opportunities for improvement. The paper evidences a fragmented policy landscape in which there is a notable lack of consistent and coherent policy and guidance across institutions, that may in fact compound existing inequalities in doctoral provision. Recommendations are made to encourage the design of institutional policies that support PhD candidates to opt for the alterative format thesis where appropriate, with wide ranging implications for the HE sector.


Introduction
Submission of a doctoral thesis in an alternative format (also commonly referred to as the journal format) is growing in popularity in the UK, having become well-established in a range of international contexts (Frick 2019;Mason 2018;Mason and Merga 2018;Moradi 2019).Instead of producing a single monograph, as is the traditional format of a doctoral thesis, doctoral candidates produce a thesis composed of a series of peer reviewed publications, either journal articles, book chapters or conference proceedings, typically bookended by introductory and concluding chapters (Carter, Smith, and Harrison 2021).In an increasingly challenging and neo-liberalised HE landscape, peer-reviewed academic publications often play an important role in securing employment in academic positions post-PhD (Moosa 2018;Roach and Sauermann 2010).An alternative format PhD has multiple benefits, both for future career prospects and as a 'safe' environment in which to develop writing skills and learn the ropes of submitting a journal article (Cameron, Nairn, and Higgins 2009;Hangel and Schmidt-Pfister 2017).The alternative format thesis also has the added benefit of extending the writing period throughout the period of study, whilst providing multiple opportunities for peer review in anticipation of the viva examination.
However, unlike HE systems internationally, the UK system has been slower to adopt the new format.Whilst the assessment criteria for a traditional doctoral thesis typically specify that candidates must produce original research of a quality that merits publication as peer-reviewed research, the approach of individual institutions is divergent, ranging from those that have yet to adopt the alternative format in any form, to institutions that have fully embraced the journal format with specific institutional policies that emphasise the myriad of benefits for doctoral researchers.There is a notable lack of consistent and coherent policy and guidance both between, and even within, institutions.In response, this paper presents a systematic narrative review to understand the development of institutional-level policies about the alternative doctoral thesis format across UK HE institutions (n = 135) (Section 3).Existing policies are reviewed to evaluate the extent to which the alternative format has been adopted across the sector, identifying best practice and opportunities for development in existing policies (Section 4).Recommendations are made to encourage the design of effective and coherent policies that support candidates to choose the alterative format, where appropriate, with implications for the HE sector internationally (Section 5).

The alternative format thesis: opportunities and challenges
The alternative format thesis differs from the traditional format of a doctoral thesis (a single monograph 1 ), and is instead composed of a series of peer reviewed publications.Appropriate publications typically include journal articles, book chapters or conference proceedings, and tend to be bookended by an introduction and conclusion.The alterative format thesis differs from a PhD by prior-publication, a typically fast-tracked process that allows those who have taken a non-traditional academic route to obtain recognition for research already undertaken that is of a level sufficient to obtain a doctorate.The format has become popular in many national contexts in recent years.For example, almost all Australian universities offer candidates a route to PhD via publications (Mason 2018).The alterative format is also increasingly favoured across African and European HE institutions, especially as a solution to long completion times for PhD study (Frick 2019;Larivière 2012).
A range of research has highlighted some of the benefits of the alternative thesis format.Typically, candidates produce more research outputs, have a higher number of yearly citations, and publish more singleauthored publications throughout their career, although this is arguably also shaped by disciplinary norms around publications (Horta and Santos 2016;Mangematin 2000).Candidates have also been shown to be more likely to complete their degree (Larivière 2012) and to develop strong international networks of collaborators (Horta and Santos 2016).Furthermore, Sharmini and Spronken-Smith (2020) argue that PhD programmes are often poorly suited to equipping candidates for future academic and research careers.The alternative format thesis is one solution for this, with Mantai (2017) noting that doctoral candidates 'begin to feel like a researcher' through the peer review process.Publications are also increasingly important in securing future employment within the increasingly neoliberal academic sector that favours a 'publish or perish' model (De Rond and Miller 2005;van Dalen 2021;Yeo, Renandya, and Tangkiengsirisin 2021).
Yet the alternative format also generates new challenges and issues for candidates and supervisory teams.Concerns have been raised about what O'Keeffe (2020) terms the 'operationalisation of the PhD student'.A focus on 'countable' work can greatly affect how the candidate prioritises time and effort, eschewing other activities such as networking or wider research culture in favour of publishing.The alternative format is also less appropriate for certain subject areas, where publishing traditional research papers is less common (e.g.practice-based doctorates) or the publication process is slower (Dowling et al. 2012).Negotiating the relationship between the supervisor and student can be more complex when devising a publication strategy and negotiating authorship of research (Xu 2020).Pressure to publish can also be damaging for mental health (Levecque et al. 2017) and lead to questionable research practices by 'perpetuating a culture in which immediacy trumps integrity' (Kiai 2019).The publication process can disrupt the typical timeline of a doctorate with its 'lengthy delays, set-backs and likely rejections' (Gravett 2021).For Moradi (2019), 'mandating publications for graduation places a poor metric on PhD students' skills and has detrimental effects on PhD training' (1025).
Existing research about the alternative format has tended to focus on the evaluation of approaches in specific disciplines (Hatch and Skipper 2016;Mason and Merga 2018;Merga 2015;Rigby and Jones 2020).Research has also focused on particular national contexts including Australia (Mason and Merga 2018;Merga 2015) and Iran (Moradi 2019).Furthermore, former PhD candidates have provided auto-ethnographic accounts of the process (Asante and Abubakari 2021;Dowling et al. 2012;Frick 2019;Jackson 2013;Robins and Kanowski 2008).However, despite the UK having one of the largest doctoral education systems in the worldtraining 25,020 doctoral candidates in 2014 (behind only the USA and Germany) (OECD 2016)there is a lack of systematic analysis of the development of policy to facilitate alternative format doctoral thesis across institutions in the UK HE system.

Methodological approach: a systematic narrative review of institutional policies
A systematic narrative review was carried out of institutional-level policies about the alternative doctoral thesis format.A systematic narrative review methodically searches for, appraises and synthesises evidence, in a narrative format.Typically results of the review are structured around: what is known; recommendations for practice; what remains unknown; uncertainty around findings; and recommendations for future research (Grant and Booth 2009).As such, the review of alternative format policies focused on the extent to which it has been adopted across the sector, before identifying best practice and opportunities for development.A number of key themes were identified iteratively as the policy review commenced informed by wider literature (Table 1).The selected themes are presented chronologically, reflecting the timeline of the PhD process: Guidelines and regulations; Terminology; Suitability of the format; Timelines; Thesis structure; Content; Structure; Publication expectations; Supervision; Student contribution; and Examination.
The scope of the review was restricted to institutional level policies focused on (i) the alternative PhD format, or (ii) wider PhD regulations that incorporated the alternative format.The review was carried out in 2022, using the most recent policies available online.In the UK, some institutions have a relatively ad-hoc approach to the alternative format thesis, producing policies at a departmental or school level.In this instance, the policies were excluded from our research.Policy documents from university institutions were only included if they were easily and openly accessible online.Finding relevant policies was made particularly tricky by the various names that different institutions adopted.Furthermore, some less research-intensive universities do not run PhD programmes, or have a smaller cohort of students.Where PhD degrees are awarded by a different institution, the university was excluded from the sample to avoid confusion.
4. The alternative format thesis in UK higher education: adoption, best practice and development opportunities Drawing on the thematic analysis carried out and wider academic literature about challenges in the HE sector, the section discusses the extent to which the alternative format has been adopted across the sector, whilst identifying best practice and opportunities for development.Several key findings emerge reflecting the need for HE institutions to: (i) address unevenness in support for the alternative format across institutions (Section 4.1); (ii) adopt common terminology across institutions (Section 4.2); (iii) support candidates to make informed decisions about the alterative format (Section 4.3); (iv) clearly define the role of the supervisor in the process (Section 4.4); (v) ensure appropriate recognition of the contribution of the PhD candidate (Section 4.5); (vi) offer flexibility in publication expectations (Section 4.6); (vii) provide coherent guidance to potential examiners (Section 4.7).

Unevenness in support for the alternative format across institutions
First, it is useful to understand which institutions have guidelines or regulations in place.Noticeably, doctorate assessment criteria in the majority of UK HE institutions stipulate that the research produced should be of sufficient quality to merit publication in peerreviewed journals.Arguably, where appropriate, the alterative format is a means of ensuring fulfilment of these assessment criteria.Yet amongst the 135 institutions sampled, some form of institutional-level guidelines or policy is identified in only 44 universities (approximately 33% of our sample).For 75 institutions, there are no obvious set of guidelines or policies allowing students to submit an alternative format thesis for examination (approximately 55% of our sample).It is worth noting however, that in several additional cases, the institution does not offer a programme of study for a PhD, or awards degrees via a different institution (n = 6).Elsewhere, relevant policies are inaccessible to anyone outside the institution, or it is not possible to identify relevant guidelines online (n = 7).At two institutions, institutional level polices are not available, as they vary between individual departments (Imperial College London; University of Oxford).
Of the 44 HE institutions that allow students to submit an alternative format thesis, provision varies there is a tendency for post-92 institutions not to offer an alternative format option, with policies being most common in research-intensive universities.For example, 58% of institutions in the research-intensive Russell Group of universities encourage students to submit an alternative format PhD thesis.Although part of a unitary system of HE since 1992, when the binary divide between universities and polytechnicals was removed, universities across the UK differ in terms of research intensity and income, and therefore the size of their postgraduate student population (Boliver 2015).There are a number of potential explanations for why a higher level of research intensity is likely to encourage institutional support for the alternative format thesis including: encouragement from research active supervisors; a larger cohort of PhD students whose work has prompted evolution in institutional policies; or the institutional prioritisation of research-based metrics such as the Research Excellence Framework (REF) (Davies and Rolfe 2009).
Arguably it is important to avoid differentiation between the experiences and opportunities afforded to PhD candidates studying at different institutions within the UK HE sector, including the opportunity to submit an alternative format thesis.This is especially important when we consider the stratification that exists in pathways to PhD study between institutions.Students studying at research intensive universities are often relatively socio-economically advantaged (Boliver 2018;Hemsley-Brown 2015;Richardson 2015;Ro, Fernandez, and Alcott 2021).Undergraduates that study at a research-intensive university are also more likely to enter into postgraduate study, at a similarly research-intensive university, where they will likely have greater access to prestigious research council funding (Pásztor and Wakeling 2018;Wakeling and Hampden-Thompson 2013).The review suggests that these candidates are also more likely to be encouraged to submit academic publications via an alternative format thesis, publications that are an increasingly vital component of career progression in the academic sector, further compounding pre-existing structural inequalities in doctoral provision (Hangel and Schmidt-Pfister 2017;Roach and Sauermann 2010).Given that the alternative format thesis sits within the existing framework of PhD assessment, developing mechanisms via which candidates can pursue an alternative format thesis as standard across HE institutions could begin to address inequalities in doctoral provision across the sector.

A common terminology for the alternative format
The terminology used to describe the alternative format at UK HE institutions varies considerably.In total, 14 names are used: alternative format; collection of papers; inclusion of previously published papers; incorporating published works in thesis; integrated thesis; journal format; paper format thesis; papers style thesis; PhD by concurrent publication; PhD by publication; publication chapters thesis; publication format thesis; thesis incorporating publications; and three-paper thesis.Whilst institutional differences in names for the alternative format might seem somewhat trivial, Kasworm (1993) emphasise that establishment of common terminology in educational settings helps to enhance specific programmes but also facilitates comparison and coordination between different institutional settings.A confluence in the name of the format across UK HE institutions would be beneficial, providing a common framework for candidates, supervisors and examiners beyond their own institution.

Making informed decisions about the alternative format
Institutional guidelines and policies are also a useful way of illustrating the potential benefits and drawbacks of the alternative format to doctoral candidates from the outset.A small number of university policies support candidates in evaluating whether the alternative format is appropriate for their proposed research.Potential benefits included: advantages in the job market; opportunity to learn how to publish; and improvements to student experience (Figure 1).Of these, the benefits for future career progression are most commonly highlighted (n = 7).Potential drawbacks are discussed less frequently but include the late availability of research results and the difference in expectations between disciplines (Kyvik and Olsen 2014).
Several institutions emphasise that the alternative format is not appropriate for all candidates and projects.One university highlights that it is 'probably a more difficult one to achieve than the traditional format'.Other universities advise that producing a thesis based on publications may not be appropriate if the research is unlikely to produce results until towards the end of the three-year registration period.Finally, some institutions emphasise that 'it is recognised the submission of an integrated format thesis may not be appropriate for all academic approaches and is likely to be more applicable in STEM based research degrees'.
The provision of information within guidelines and policies about the benefits and drawbacks of the alternative format in this instance is likely to be particularly useful, prompting early discussions with supervisors to support candidates to make an informed decision about the most appropriate pathway.It is important that doctoral candidates do not feel pressured by the alternative format to publish just for the sake of it, especially in the context of wider debates about the incentivisation of publishing via a 'publish or perish' academic model, that incentivises 'questionable scientific practices' (Kiai 2019) and can have negative impacts on student mental health (Levecque et al. 2017).Yet this type of information is infrequently provided by institutions, that instead rely on the doctoral supervisor to support the student in their decision (Section 4.4).It would be beneficial for institutional policies to provide a more complete picture of the benefits and drawbacks of the format from the outset to guide these supervisory conversations and decisions, possibly drawing on the growing body of research and evidence reviewed in Section 2.

Defining the role of the supervisor in process
Supervisors play an important role in the successful publication of papers during a candidates PhD (Kwan 2013).Kamler (2008) recognise that co-authorship with supervisors is a 'significant pedagogic practice' that can enhance experience of the research process and the quality of research outputs.However, Merga and Mason (2021) evidence how mentor and peer support is not universal in examples of Australian and Japanese institutions, with some students not benefiting from support in the production and translation of research outputs.There is debate about the extent to which supervisors should assist students, and the risks of doing so (Xu 2020).Nethsinghe and Southcott (2015) argue that the format involves 'a dialogue between supervisor and candidate involving the resolution of sometimes conflicting demands'.There is also debate about whether the model entitles supervisors to be co-authors, and the extent to which a student has ownership over the decision about which format is best suited to their needs (Xu 2020).
In the examples of policies reviewed, few provide extensive guidance about the role of the supervisor.Several policies emphasise that the supervisors should be involved from the beginning (n = 15), with one institution emphasising that 'the decision to undertake a PhD by Paper Format should be supervisor-led'.Others stipulated that other staff members and committees should be involved, including the Director of Doctoral Programmes; the Head of Department; External Examiner(s); and Postgraduate Monitoring Committees.Only one institution specifies that the decision to opt for the journal format thesis should be taken by the student, and that they should not feel pressured to make the decision by supervisors (see Section 4.5).Kamler (2008) argues that there is a need to 'rethink co-authorship more explicitly as a pedagogic practice, and create more deliberate structures in subject disciplines to scaffold doctoral publicationas it is these structures that influence whether graduates publish as informed professionals in their chosen fields of practice.'Supervisors assume a central role in this 'scaffolding' and clear expectations of the supervisor-student relationship should be established in all institutional guidelines and policies.

Recognition of the contribution of the PhD candidate
Authorship of academic publications identifies and recognises the contribution of individuals to published research (Smith et al. 2020).As a key measure of research productivityh in the neoliberal HE sector, authorship influences future career progression and is of particular importance for early-career researchers navigating a competitive academic job market (Smith et al. 2020).Yet concerns about a lack of recognition of certain types of researchers in collaborative research processes are well documented over several decades, including a systematic lack of recognition based on seniority, gender, race and other forms of social difference (Gómez-Ferri et al. 2019;Hedt-Gauthier et al. 2019;Heffner 1979).For example, researchers that are junior in hierarchical academic structures are typically more dissatisfied with co-authorship than relatively higher-ranking staff members (Gómez-Ferri et al. 2019;Smith et al. 2020).
Most institutions that facilitate the alternative format thesis in our sample stipulate that a statement detailing the student's contribution to each publication must be included in the final thesis.Typically, this statement will detail co-authors and their individual contribution to each publication.Yet it is surprising to find very limited discussion in existing policies about how candidates should negotiate the authorship process.One of the only institutions to discuss the authorship process stipulates that 'at an early stage, the student must agree an appropriate order of authorship with their supervisors and other coauthors'.Another advises that 'supervisors and PhD researchers may wish to discuss early on in the writing process issues such as author order, percentage inputs to a paper, and how any revisions will be handled.' Institutional policies differ substantially in their expectation around students being primary author of publications.Of the institutions that facilitate the alternative format in our sample, approximately 46% provide further recommendations about the contribution of students to publications, especially those that are co-authored (n = 21).Several institutions specify that the candidate is expected to have made the primary contribution to all published works included.For others this extends to the student having taken the leading role in all aspects of the research, from the study design to data collection, analysis and writing.A handful of institutions provide specific recommendations about the extent of the student contribution, including one that recommends that 'it would be expected the candidate would be the lead author, contributing at least 75% of the substantive content'.Elsewhere, advice around student contribution is less prescriptive, reflecting some of the realities of working as part of multi-disciplinary research projects.
Learning to manage the publication process, including the management of the relationship with coauthors, is a key skill acquired whilst producing an alternative format PhD (Conn and Jefferson 2017;Lei and Chuang 2009).However, to prevent misrecognition or exploitation of a candidate's contribution to research it is important that alternative format guidelines clearly define expectations around how contributions are recognised.Assigning and negotiating authorship can be challenging, especially as an early-career researcher engaging with more senior academics (Haerling and Prion 2020).Authorship attribution is especially complex in disciplines that favour multidisciplinary ways of working, requiring a variety of contribution types from a range of individuals with specialist skills (Gibbons et al. 1994;Smith and Williams-Jones 2012).Such discussions are widely feared due to the strain they can place on interactions within a research team (Smith et al. 2020).Smith et al. (2020) recognise that although values of fairness and transparency are widely promoted by researchers, rank and desire for success can overpower ethical decision-making.Strong guidance at the institutional level can help to train candidates in ethical publication practices, and shield them from relatively exploitative practices.

Flexibility in publication expectations in the alternative format
Publication expectations for the fulfilment of an alternative format PhD thesis are one of the most variable themes within the institutional policies reviewed.Publication expectations extend to the number of publications, their publication status, and the type of journal or outlet they are published in.Some institutions make recommendations about the minimum number of papers; published papers or submitted papers; or the maximum number of papers (Figure 2).In this instance, many universities avoid being too prescriptive, acknowledging that number of papers is likely to vary across disciplines.When stipulating a minimum number of papers, three papers is most common (11% of available policies).Even fewer institutions require candidates to have actually published a certain number of papers (approximately 9% of available policies).In this instance, the preferred recommendation is for at least one paper to be published in a journal.
Several policies also make recommendations about publication outlets, referencing international, highquality and reputable journals.Some use journal metrics as an indication of the standard of publication expected e.g. a journal with an impact factor.It is worth recognising however, that journal metrics are often misused and can be misleading (Morales et al. 2021;Pendlebury 2009) and the process of evaluating different journals is likely to require considered input from an experienced supervisor, an issue unacknowledged in the majority of policies.
In most institutional policies reviewed however, there is no indication of the number of papers that a PERSPECTIVES: POLICY AND PRACTICE IN HIGHER EDUCATION candidate should include in an alternative format thesis (85% of policies reviewed).Such flexibility has several strengths, overcoming some of the barriers to pursuing an alternative format thesis by reducing the potential for the publication process to disrupt the typical PhD timeline (Gravett 2021), as well as helping overarching institutional policies account for differing publication practices between disciplines (Larivière 2012).Yet, whilst there is benefit to avoiding setting overly prescriptive expectations around outlets for publications, alternative format guidelines and policies provide a learning opportunity to help candidates to avoid the pitfalls of predatory publishers that do not subject research to rigorous peer review (Yeo, Renandya, and Tangkiengsirisin 2021).

The role of the examiner when assessing an alternative format thesis
Presenting a thesis in which the majority of research has already undergone peer review is likely to change the examination process.In the handful of university policies that discuss the strengths of the alternative format, a key benefit identified is that of the external examiner being presented with work that has already undergone peer review.Some institutional policies acknowledge that the peer review process provides a strong indication of the quality of the research from the wider research community.Whilst journal ranking is not a component of the examination process (as stated in the majority of guidelines) examination of the alternative format thesis in a research intensive HE institution in New Zealand found that 86% of examiners were highly influenced by publications in the top-ranked journals and international peer-reviewed journals (Sharmini et al. 2015).
In spite of this, few policies made specific recommendations about how the examination of an alternative format thesis might vary from that of a PhD presented in a traditional thesis format.This is likely related to the emphasis that the majority of universities place on the alternative format being positioned as a variation of the traditional PhD thesis.As such, examiners are asked to regard the alternative thesis as a piece of work that must meet the requirements of a doctoral degree as prescribed in the overarching doctoral research regulations and policies.Several policies emphasise that even if papers have undergone peer review and been published, they are not beyond the scope of examination.Here, emphasis is placed on ensuring the examiner is able to critically examine the work presented.Power to examine the entire thesis, irrespective of publication, is particularly important given that whilst a paper may have been accepted as an individual research contribution, alone it is unlikely to constitute the body of original research necessary to constitute a PhD qualification.
However, in some instances where new policies have been designed to accommodate the increasingly popular format, specific recommendations are made to examiners about how best to assess an alternative format thesis.For example, one institution offers advice to examiners about themes to consider during the viva examination, acknowledging that the presentation of a thesis as a collection of papers is likely to be quite different if the majority of the work presented has been published or accepted for publication.Examiners are encouraged to judge based on coherence; originality; the intellectual contribution of the research; understanding and explanation of the wider context within which the research sits; and implications for future research.Provision of advice to external examiners about assessment of the alternative format PhD thesis is a useful mechanism via which to foster coherence in approaches across the sector.

Concluding remarks
This paper presents a systematic narrative review of policies and guidelines about the alternative PhD thesis at UK HE institutions, providing new insight into the fragmented manner in which the format has been adopted across the sector.Whilst some institutions have embraced the increasingly popular format, offering well developed and transparent guidance, it is evident that the format is still somewhat in its infancy, with only a third of the sampled universities supporting it.Availability of the alternative format at only selected UK HE institutionstypically (although not exclusively) those that are relatively research intensiverisks disadvantaging candidates enrolled at institutions that do not currently facilitate it.This is especially pertinent in the neo-liberalised HE landscape in which peer-reviewed academic publications play an important role in securing employment in academic positions in many disciplines post-PhD (Moosa 2018;Roach and Sauermann 2010).
Based on our review we make seven recommendations.As a sector, UK HE should focus on addressing inequalities in support for the alternative format across institutions.There is the potential for a national, representative body of postgraduate matters to identify good practice guidelines for the sector.This would allow for candidates, supervisors and examiners to be more coherent and in-keeping with one another across the sector, adopting a common language and set of expectations for all HE institutions.Given the myriad of challenges associated with publishing research during PhD study, and the infancy of the format in the UK, universities should have well-developed structures in place to support candidates.Candidates should be supported by their university to make informed decisions about the alternative format, in order to get the most out of the PhD research process.For those who opt for the alternative format, it would be especially beneficial for institutional policies to clearly define the role of the supervisor in the process from the outset, ensuring that there is appropriate recognition of the contribution of the work of the PhD candidate.Flexibility in publication expectations is also important, in addition to providing coherent guidance to potential external examiners.PhD candidates will then be better positioned to evaluate whether the alterative format is the thesis format that best meets their individual needs.
That is not to suggest that all PhD candidates should be expected or encouraged to produce an alternative format thesis based on publications.Indeed, there are a range of challenges associated with the alternative format thesis that should be considered before a candidate decides how to present the results of their PhD research (Kiai 2019;Levecque et al. 2017;Moradi 2019;O'Keeffe 2020;Xu 2020).Rather it is to advocate for candidates to have the option to pursue an alternative format, if they decide that it is appropriate with the support of their supervisor.

Figure 1 .
Figure1.Frequency of benefits and drawbacks of the alternative format thesis discussed in policies and guidelines reviewed.

Figure 2 .
Figure2.Proportion of institutional alternative format guidelines or policies that recommend a (i) minimum number of papers; (ii) minimum number of papers published; (iii) minimum number of papers submitted to a journal for review; and (iv) a maximum number of papers.Proportions based on 44 institutional policies identified during the review.

Note 1 .
A monograph thesis presents the PhD research as a unified text structured in chapters, book ended by an introduction and conclusion, with the PhD candidate as the sole author.

Table 1 .
Systematic narrative review themes and questions.