1 Introduction

Doctoral examiners play an influential role in the doctoral assessment, as they are tasked with evaluating a doctoral candidate's research and recommending the assessment outcome. Examiners are academics or experts in a particular field, and their appointment is typically made by the university where the candidate is enrolled, with selection based on the examiners' expertise in the relevant field of research. Examiners may either be affiliated with the candidate's university, serving as internal examiners, or from an external university. The selection criteria and appointment of examiners vary across universities worldwide [1,2,3,4].

Examiners evaluate a doctoral candidate's research by completing two tasks: assessing the written thesis and participating in the viva or oral examination. Examiners will first read the thesis submitted by the candidate, and then discuss it with the candidate in an oral examination. The candidate is required to defend the thesis during the viva to pass the assessment [5]. As researchers noted that the decision of whether the candidate passes or fails can only be made after the viva [6], thus making it the final doctoral assessment in different doctoral education contexts, including the UK, New Zealand, and Malaysia.

In the doctoral assessment, examiners must ensure that the work meets the high standards set by the discipline and that it makes an original contribution to the field. Examiners must assess the quality of the research and the validity of the arguments presented in the thesis and consider the extent to which the research advances the existing knowledge [7, 8]. During the oral examination, examiners question the candidate on their research, evaluating their understanding of the subject matter and their ability to engage in scholarly debate and defend their research [9,10,11]. Ultimately, the evaluation process undertaken by doctoral examiners is essential in upholding academic integrity and ensuring the quality and relevance of the research produced by doctoral candidates.

Despite examiners being the gatekeepers of the doctoral assessment, their practices, particularly in the viva, have been relatively underexplored. One main reason for this may be the restrictive access to the closed-door viva in many countries, such as the UK and Malaysia. Researchers have pointed out that the PhD viva “is seldom witnessed/observed by anyone not involved in the examination process, which poses challenges both for monitoring and for researching the assessment process” [12]. This lack of access prohibits new examiners or candidates from equipping themselves with 'insider' knowledge of viva practice. While there is a growing body of research on viva, much of this research has focused on the experiences of doctoral candidates rather than examiners' perspectives and practices. As a result, there is limited understanding of how examiners in different doctoral assessment contexts approach the viva.

In this paper, to address the knowledge gap on how examiners approach the PhD viva, I ask the following question: What are the examiners' conceptualisations of the purposes of the PhD viva? The aim is twofold. First, to better understand how doctoral examiners perceive the viva to increase the transparency of the closed-door examination [4] and for quality assurance [12]. Second, to help doctoral examiners approach the viva effectively since there is a lack of learning opportunities for viva examiners, especially within the Malaysian context [13], and the viva "is often a source of concern and confusion for many supervisors and examiners" [6].

2 The PhD viva and its purposes

The conduct of the PhD viva, which is shaped by each respective university's policies, differs between contexts. Even within the same country, the conduct of the PhD viva may be diverse [2, 3]. The variations in the university policies and practices of the PhD can make the purpose of the viva unclear. However, most researchers tend to agree that the viva serves the purpose of examination [6, 14, 15]. In a prominent study conducted by researchers in the UK [6], the researchers argued that a viva has three broad purposes: examination, development, and ritual, of which the main purpose is examination. In the viva, examiners act as gatekeepers by carrying out a series of evaluation tasks to ensure that the candidate possesses the qualities to be “a credible member of the academic community” [16] and to receive the highest award, a PhD from the university. Examiners, as reported by researchers [6], usually examine for the authentication of the candidate's thesis, the candidate's ability to locate PhD research in the broader context, the candidate's understanding and ability to produce and present research to PhD standards, the candidate's ability to defend the thesis, the final decision of borderline cases; clarification of obscurities and areas of weakness, the candidate's oral skills, and the qualities to be accepted into the academic community (gatekeeping).

Researchers have also examined and reconfirmed these purposes in the New Zealand context. A researcher [14] conducted a focus group discussion with academics and reported that the purpose of a viva is an examination. Similarly, PhD candidates were surveyed and found that they perceived the purposes of the PhD viva to include the clarification and authentication of the thesis and a test of broader knowledge of the field; that is, an examination [15]. However, the examination practices in New Zealand universities differ, and some universities do not regard the viva, commonly known as the oral, as a pass/fail type of examination, as supervisors and candidates have access to the examiner reports and viva questions before attending the viva [17].

A second purpose of the PhD viva is related to the opportunity for development. As examiners critically examine the candidate's written thesis, they often provide two types of developmental feedback: basic and advanced [6]. For basic development, examiners provide feedback for the candidate to improve the quality of the thesis if the thesis is not at a PhD standard. If the standard of the thesis is at the PhD level, the examiners will provide advice about future publishing and career. However, examiners do not always provide basic and advanced developmental feedback at the same time. This usually depends on the quality of the thesis [6].

A third purpose of the PhD viva is a ceremony or ritual to mark the end of the doctoral journey. A researcher highlights that “life-changing events need to be marked by a rite of passage, and so it is with the doctorate where it is traditional for the final examination to be an oral one” [18]. In other words, a PhD viva is a ritualistic event for a candidate who has spent several years working on a PhD. This is certainly the case in Scandinavian countries, such as in Sweden, where the university published the candidate's work before the defence [19]. However, in the UK, the PhD viva is focused on assessment, with the ritualistic aspect only regarded as one of the viva's purposes [6].

Even though the three broad purposes of the viva—examination, development, and ritual—have been identified, a viva is unlikely to achieve all three purposes. The viva's purpose is decided by the quality of the written thesis [6]. The researchers illustrate that when the quality of the thesis is good, the purpose of the viva is for authentication, idea development and advice on publication. When the quality of the thesis is poor and indicates failure, the viva is used to confirm the result as a failure. When the quality of the thesis is borderline, a viva helps the examiners decide whether the thesis could be improved to meet the standards of a PhD [6].

While Tinkler and Jackson's list of tasks that examiners undertake in the viva provides a valuable understanding of the examination purposes, there is very little understanding of how examiners decide the examination purposes. Since the PhD viva has different examination purposes and it is unlikely that all the purposes will be achieved, it is crucial to examine the purposes in different doctoral education contexts, such as Malaysia.

3 Background and context

In the Malaysian doctoral education context, the 'PhD viva' is a widely used term to describe the oral examination as an integral part of the doctoral assessment in universities. This oral examination has three main features. Firstly, it is a mandatory oral examination, and a candidate must participate in the viva after their written thesis has been examined. A final decision on the doctoral assessment can only be made after the viva. Secondly, the viva is a closed-door event; only invited members are allowed to participate and know what happens in the viva, which is consistent with UK practices [4]. Supervisors will usually be invited to attend the viva as silent observers. Lastly, it is worth noting that a re-viva is an option in the doctoral assessment process. If the examiners are not satisfied with the candidate's performance in the viva, they may request a re-viva. Additionally, whether a pass or fail, the viva's outcome will significantly affect the overall assessment outcome.

The PhD viva is divided into three parts: the pre-viva meeting, the viva talk, and the post-viva meeting (Fig. 1). The pre-meeting involves the chairperson and examiners discussing topics to be addressed in the viva. The viva talk involves a short presentation by the candidate followed by a Q&A session. Examiners are free to ask any questions about the thesis. After the viva, a post-viva meeting is held to review the candidate's performance and finalise the assessment outcome. If the thesis is accepted, the candidate has a set amount of time to make any necessary corrections. If the outcome is for resubmission or re-viva, the candidate must resubmit the thesis or re-sit the oral examination.

Fig. 1
figure 1

A typical PhD viva at a Malaysian university

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4 Methods

A Malaysian university was selected as the research site for this study. The university, labelled MY University, is a public research university that offers a wide range of doctoral programmes and adopts a compulsory closed-door viva as part of the doctoral assessment. Doctoral examiners who participated in the viva were purposively invited to participate in the current study via email. Informed consent was obtained from all the voluntary participants involved in the study before the commencement of the interviews.

Adopting a qualitative research design, semi-structured interviews were conducted with twelve examiners (five males and seven females) on their experiences and practices in the PhD viva. All the examiners had examined at least ten PhD vivas at MY University, and they were associate professors or professors, except one examiner. Each interview lasted approximately one hour and was audio-recorded and transcribed verbatim. This paper focuses on the purposes underlying examiner practices as part of a more extensive study. Questions asked include: "As an examiner, what are you trying to achieve in a viva?" "How do you make a decision in the PhD viva? Will you change your initial decision? If so, why?" The transcribed interviews were analysed using a qualitative thematic analysis [20] to identify themes. This qualitative approach involved an exploration of data, allowing for the emergence of patterns, themes, and categories. The themes were examined in connection with the literature and MY University policy to add robustness and depth to the interpretation of the data.

5 Findings

Analysis of the narratives of examiners on their practices in the viva revealed that the viva served four main purposes: (i) gatekeeping, (ii) empowerment, (iii) dialogue and (iv) enculturation. Each purpose is presented according to the emphasis of examiners in the interviews and is further discussed.

5.1 Gatekeeping

The main purpose of the PhD viva, according to the examiners in this study, is gatekeeping, which involves examining the quality of the research thesis and discussing it in the oral examination. The examiners have a responsibility to ensure the quality of the thesis is at the PhD level and expressed four viewpoints, which are authenticity, doctoral quality, contribution to knowledge, and feedback. Ensuring authenticity is crucial, and it is the job of the examiners to ensure that candidates write their own thesis since the PhD is the highest degree the university offers and is recognised internationally. A recurrent narrative illustrated by examiners such as Nancy is:

… when we ask questions, the purpose is to find out whether the work is genuinely done by the student. So that is, that is, also one of the functions whether, you know, that the student actually spends the effort in doing the work or whether it was done by another person. We ask questions. You know, if the candidate fails to answer several questions. There is a big doubt that you know, he did not, he or she did not spend the time, you know, in working on the, their research or their study.

(Nancy)

Nancy's perspective on gatekeeping focuses on verifying the authenticity of the written thesis and research to prevent academic dishonesty and research misconduct [21]. She checks if the thesis is reliable, original, and not plagiarised and ensures that the presented research is authentic and conducted by the candidate. Like other examiners, Nancy expects the thesis to be written ethically and conducts authenticity verification during the viva.

Another view of gatekeeping is that the examiners assess whether the thesis is of doctoral quality. It is expected that the thesis presented in the assessment will be at the PhD level, according to the standards of MY University. Some examiners (Thomas, Sally and Cassie) explicitly expressed that they check whether the candidate's thesis meets the PhD requirement. For example, Thomas stated that:

First of all, we would like to know the whether the scope of work for a PhD candidate is it sufficient to cover, I mean, to actually, at the end of the viva session, we give a Pass, you know, or Fail to a candidate but when we give, decided to pass the candidate, so are they sufficient to let the candidate carry the, the, I mean, the name, I mean doctorate, so, which is very important that we look at the scope of work.

(Thomas)

For Thomas, the breadth and depth of the thesis are indications of quality. He aims to discover whether the thesis has adequate research coverage to warrant the PhD degree. Then he makes a judgement based on the thesis presented. His notion of breadth and depth is in line with other examiners who were interviewed.

A third view of gatekeeping, in which all the examiners agreed, is determining the contribution to knowledge. For a PhD, a contribution to knowledge is the most important criterion, which distinguishes the quality of the thesis as either a master's degree or a PhD [22]. An example narrated by Rebecca is:

We're not looking for new knowledge contributions that will blow up the world you know. But for the PhD, you're expecting something new to the body of knowledge that's in the field, okay? And this, this new contribution, they call it new knowledge contribution must be gained through a very rigorous intellectual process, and this must be evidenced through the writing and also in the presentation you know that this student actually has done the thinking the analytical process and they know what they are talking about. No matter what's, what comes out of that, right?

(Rebecca)

Rebecca's view on contribution to knowledge in a thesis is not necessarily about changing the world but about making a meaningful addition to the existing literature. She believes that a candidate should present some originality in their research, which could expand on or add to current knowledge in the field. This idea aligns with the argument put forth by researchers [23], who outlined six ways in which originality in a PhD thesis could be demonstrated. Moreover, Rebecca expects evidence of the candidate's thoughts and actions towards their proposed research problems. However, it should be noted that different examiners may have varying expectations regarding knowledge contribution [7], depending on the thesis topic and the candidate's discipline [8].

Lastly, examiners understand that their gatekeeping responsibility does not end with just examining the thesis but also providing constructive feedback to the candidate. Two examiners (Lambert and Sally) mentioned that providing recommendations for improvement is an essential part of their role as examiners, and they believe that offering suggestions for improvement can help candidates achieve the doctoral quality required for a PhD thesis. For instance, Sally stated that:

…as long as the thesis meets the rigours of research and the, the platform is sound, the methodology is sound, I usually don't, you know, kill a student. I would just usually if there's work that needs to be improved on, and I would definitely make suggestions to improve on it.

(Sally)

If an initial assessment finds that the thesis is unsatisfactory and needs improvement, Sally offers developmental guidance to help the candidate improve the quality of their work. This feedback for improvement is essential to the gatekeeping responsibility, as it helps maintain the PhD standards. Sally's approach is in line with the findings of existing researchers [24], which suggests that the oral examination provides a valuable opportunity for the basic development of the candidate.

5.2 Empowerment

In addition to gatekeeping, the PhD viva serves the purpose of empowerment. This involves candidates defending their theses and demonstrating mastery of the chosen research subject. Examining the candidate's ability to communicate and asking for clarification are ways in which this purpose is fulfilled. The viva allows candidates to clarify arguments and expressions in their thesis, ensuring that examiners can ascertain their mastery of the research topic. This is particularly important when the thesis is unclear or open to different interpretations by examiners. Hellen indicated that:

Okay. Clarification because before the viva, examiners were given a thesis to read, to go through. So, when I read the thesis, some of the thesis there are, you know, statements that are not clear, there are methodologies, for example, which are not clearly stated or clearly presented in the thesis so, for the clarification on these points need to be clarified during the viva. At the same time also, I need clarification as for those things that I mentioned to you which is not being properly defined in the thesis.

(Hellen)

Hellen's approach to the viva is focused on empowering the candidate to help themselves on their own terms. She delegates power to the candidate to justify or provide further explanations on unclear areas of the thesis. This ensures that the thesis has a sound argument and that the methodology is acceptable. Furthermore, examiners clarify areas that are considered weak. Rebecca, for instance, asserts that:

…we just highlight what is the weakness or what's the strength and where to test the student. So after the orals, for those the weakness that we see and is already answered, okay, we just chuck away so we know it's covered….

(Rebecca)

Rebecca seeks clarifications on the weaknesses of the candidate's thesis in the viva. If the candidate can provide satisfactory explanations or answers to the questions posed by her, Rebecca will normally accept the responses.

Testing the candidate's communicative ability in the oral examination is another purpose of empowerment. Examiners enable a candidate to defend their ideas and justify their rationales and the way in which their study was conducted, so that examiners can gauge whether the candidate is the subject expert. Examiners want to determine if the candidate possesses the ability to defend and claim expertise. As illustrated by Cassie:

This is more like you want to see whether the candidate has this PhD ability [to explain orally] because what they have given you is just a written thesis.

(Cassie)

In Cassie's narrative, it is evident that the candidate's ability to communicate their research is crucial in demonstrating their expertise. The candidate is expected to clearly articulate their points during the viva, using appropriate language and terminology that showcase their knowledge of the subject matter. Cassie's emphasis on clear communication highlights the importance of not only having knowledge, but also being able to effectively convey it to others, which is an essential skill for any academic or researcher.

5.3 Dialogue

The PhD viva serves as a platform for dialogue between the candidate and examiners, as well as an opportunity for the candidate to communicate their research. In addition to giving short presentations of their research, candidates are expected to engage in discussion with the examiners. Some examiners (Thomas, Nancy, Hellen, and Sally) highlighted that the viva also tests the candidate's ability to express ideas like a scholar, present research, and engage in scholarly discussion. The candidate's ability to communicate their research clearly and effectively is crucial in demonstrating their expertise in the field. As Thomas explains:

Yeah. So, this is what many of us say that it is the final quality control stage. Yeah. Because a candidate may be very good with their thesis, but they have no interpersonal skills to present their work….

(Thomas)

Thomas believes that the ability to communicate the outcome of research effectively is essential. He elaborates that research should not merely end up in a thesis but should be disseminated through other channels such as seminars or conferences; otherwise, the study's worth would be less valued. Therefore, the viva serves as the ultimate platform to evaluate a candidate's ability to orally present their research, making it a communication event [25].

In addition, candidates are expected to be able to discuss their work, defend their ideas, and respond to criticisms or questions from examiners. An example from Hellen is as follows:

… and you're able to explain what processes you took, why you did this this way and not that way and so on so forth, why did you analyse your data this way and not that way, for example, yeah? So if you think you're unable to, to do that, it can work negatively for you.

(Hellen)

Hellen, like other examiners, places importance on the candidate's responses during the viva. She expects the candidate to have a strong and convincing stance on the matters discussed and uses their responses to make her decision. If the candidate's responses are inadequate or unconvincing, this may have an impact on the viva process and the outcome of the assessment. Candidates who cannot communicate to the satisfaction of the examiners will likely be scheduled for a second viva. At MY University, a re-viva is not uncommon. An examiner, Lambert, shared the experience of a candidate who failed the viva twice despite having a good thesis because the candidate struggled with oral communication due to anxiety. The examiners then allowed the candidate to provide written responses to the questions and passed the assessment once they were satisfied with the answers.

5.4 Enculturation

The viva serves the purpose of enculturation in which the candidates are socialised into the disciplinary community. A candidate who successfully obtained a PhD will become a member of an academic discipline, and examiners play an important role in the candidate's PhD process, similar to their supervisors. While supervisors guide candidates towards research completion, examiners are responsible for examining the research and the candidate. In addition to giving feedback and suggestions for improvement and advancement, examiners test the candidate's knowledge. All the examiners expressed the idea of disciplinary knowledge testing as part of the viva. Examiners stated that they tested the candidate's understanding of their research and general knowledge in the field. For example, Hellen explained:

We will ask simple questions or questions related to the keywords… If they say that they are majoring in database, for example… they must know what the database is in the first place before they can say that they are an expert in database. Okay, database is a very huge area. There are many issues, and they select particular issues, for example, as mentioned to you, query processing. So, they must know exactly what query processing in the first place is and how it works. So this is showing that they know the basic concepts related to the area, and then we move to something more specific to what they have done.

(Hellen)

Hellen indicates that the candidate must have a basic understanding of the knowledge in their research field. To hold a PhD degree in a relevant field or be called a disciplinary expert, the candidate should demonstrate a good grasp of the knowledge in the field. The candidate is then expected to situate their research into the broader field. When the candidate exercises their thoughts and actions like a disciplinary member, it shows that the candidate has been socialised into the disciplinary community. However, the process of socialisation does not just happen in the viva. Rather, it starts the moment the candidate begins their PhD journey. The viva completes the socialisation process, allowing examiners to assess whether the candidate has truly become a member of the academic discipline and is capable of contributing to it in meaningful ways.

6 Discussion

From the examiner's view, the purposes of the PhD viva could be conceptualised as gatekeeping, empowerment, dialogue, and enculturation. Among these four purposes, gatekeeping is the fundamental purpose of the assessment. Completing the doctoral assessment, including examining the written thesis and participating in the viva, is a main priority for the examiners. An explanation for this is that examiners want to fulfil their duties as gatekeepers and quality controllers [26]. At MY University, the outcome of the doctoral assessment cannot be finalised without participating in the viva. All the examiners mentioned that the tasks they completed in the viva, such as checking the doctoral quality of the thesis, serve the purpose of gatekeeping. This view is consistent with previous studies conducted in the UK [24] and New Zealand [15].

In serving the purpose of gatekeeping, checking for authenticity appears to be an indispensable task. In this study, examiners unanimously reported checking whether the candidates wrote the theses themselves. One examiner mentioned an encounter with a candidate who translated some parts of the thesis from one language to English. Because the writing expressions were different, the examiner was suspicious. When probed in the viva, the candidate admitted she had translated and copied from a study conducted in another language. This incident shows the important role of examiners in authorship verification, as text-matching software such as Turnitin and SafeAssign are not able to detect translation. This incident also gives rise to potential issues in assessment, which perhaps have not been reported in the literature, apart from collaborative authorship [24], in which the candidate was not the sole author of the study.

In addition to gatekeeping, examiners also empower candidates and engage in dialogue. The candidates are presented with the opportunity to defend their research and show mastery of the research subject by engaging in discussion with examiners. This process involves questioning by the examiners, which may be perceived as disempowering or challenging the expertise of the candidate. However, it is necessary for the examiners to ask questions and seek clarification from the candidates to complete the examination.

Moreover, the doctoral assessment is a unique opportunity for a discussion to take place in the viva, and feedback will be given. Candidates are expected to explain and clarify any doubts the examiners may have about the thesis and incorporate their feedback into the final revision. If examiners report serious concerns, they usually want to help the candidate salvage the research [22]. They would also provide feedback and suggestions to the candidates to improve the quality of the research [24, 27, 28], as the thesis is often regarded as a work in progress [29]. If there is no critical concern about the thesis, examiners will provide advice on further research, career advancement or future research collaboration [24]. Ultimately, the examiners want the candidate to pass due to the work and time invested by the candidate in doing the research [1].

However, the PhD viva should not be considered merely an assessment that serves the purposes of gatekeeping, empowerment, and dialogue. It has a strong aspect of discourse socialisation or enculturation, in which the candidate is socialised into the discourse community. The notion of the discourse community proposes that examiners are experts in the discipline and socialise new members to the discipline by assessing the candidate's learning, helping them become legitimate members of the discipline [30]. Candidates who pass the viva successfully will be recognised as scholarly members capable of conducting and disseminating research of interest to the disciplinary community. This integrated view of assessment and discourse socialisation is largely supported by research into examiners' views of the purposes of the PhD viva in the British context [24].

Another notable observation from the findings is that the candidate's performance influences the purposes that shaped the process and outcome of the viva in the PhD viva. Examiners conduct the viva and make final assessment decisions based on the candidate's ability to engage with and convince the examiners. If the candidate's performance in the viva does not meet the satisfaction of the examiners, this has consequences for the conduct of the viva, the decision-making of the examiners, and the outcome of the assessment. For instance, if a candidate fails to present convincingly in the viva, there may be doubts about whether they did the study; thus, the suggestion for a re-viva may be considered. As such, the candidate's ability to engage with the examination committee is heavily weighted in decision-making. This finding resonates with the view of a scholar [10] that the viva is indeed an assessment of the thesis, research and researcher. Writing a quality PhD thesis on a research topic is not sufficient; a candidate must be able to justify or defend it to examiners in a convincing and articulate manner.

Consequently, this observation reinforces the importance of oral performance in the PhD viva. The candidates' performance will likely influence the assessment outcome, whether good or poor. One anecdotal piece of evidence of this view is that a candidate at MY University had to re-sit a viva because of the unsatisfactory responses they provided in the viva [11]. Although the candidate had an impressive list of publications, she was still expected to be able to put forward acceptable responses in the PhD viva. While examiners often make their decision before the viva, this decision can only be confirmed after the viva. If the candidate cannot provide satisfactory responses in the viva, they will be given a chance to sit for a re-viva, or they might be given a written test, according to an examiner in this study.

While recognising the importance of the conceptions of purposes in guiding examiner practices during the PhD viva, it is imperative for examiners to create a supportive environment. This can be achieved by embracing a student-centric approach, wherein examiners not only evaluate the candidates’ knowledge and research skills but also contribute to their overall learning experience. Ultimately, the PhD viva is not merely an oral examination; it also serves as a doctoral rite of passage. Therefore, examiners should ensure that the PhD viva leaves a positive and indelible mark for candidates.

7 Conclusion

The findings of this study provide a conceptual understanding of the multifaceted purposes of the PhD viva, highlighting their integral role in the examination process. While the gatekeeping purpose of the viva is widely recognised, the study reveals that other equally important purposes, such as empowerment, dialogue, and enculturation, are necessary for achieving the ultimate aim of doctoral assessment. Therefore, the conceptualised purposes of the viva serve as a valuable theoretical contribution to the doctoral assessment literature and could be disseminated among academics.

Existing examiners may review and align their examination practices with the purposes and ask effective questions [9, 31] to elicit responses in the PhD viva, which will help them in assessment decision-making. In addition, academic developers who facilitate professional development programmes may share and discuss the assessment purposes with novice doctoral supervisors and examiners. Emphasising the facilitative role examiners should play in the viva will ultimately benefit the candidates and the doctoral community.

It should be acknowledged that the generalisability of the current findings may be limited due to the specific format of the PhD viva in Malaysia. While the purposes of the viva may be applicable to other universities or countries with a similar viva format, it may not be relevant to those with different structures or processes of the oral examination, such as Canada or Scandinavian countries. Therefore, further research is needed to explore the assessment purposes of different viva models in other contexts. Additionally, future studies could expand on the current study by conducting cross-national comparisons or examining different disciplines to provide more insights and recommendations for viva practices in doctoral education.