Producing Planning Knowledge: How Professional PhD Candidates Bridge Research–Practice Divides

This paper addresses an important, but under-studied, pathway for knowledge production in the field of urban planning: the practitioner engaging with academia through the writing of a PhD. Drawing on our own experiences of doctoral mentoring, in dialogue with PhD candidates, we reflect on the questions and challenges this form of knowledge production raises. The paper aims to extend planning theory’s recognition of ‘multiple epistemologies’ (Sandercock, 2003) through a deeper understanding of how planning professionals as authors lead the translation of experiential knowledge into academic knowledge. Understanding why this is so difficult to actually (co)produce should lead us not only to better mentoring, but also to critical reflection on how rigorous and relevant knowledge is defined within planning academia.

(temporarily or permanently) from their previous practice, and to reflect on it, making their role in knowledge production complex and interesting. Whatever their (actual or former) position in local government hierarchy, they have unique professional insights, experience and understanding which they can deploy in producing academic research. At the same time, relationships between these two forms of knowledge can be unclear, and the expectations of what constitutes valid academic knowledge can be intimidating and confusing. For these candidates, producing a PhD is also interlocked with a move into the academic sphere that requires them to reflect critically on their planning roles and experiences, possibly questioning elements of these they value deeply, or which have been central to their professional identities. Professional PhD candidates are therefore faced with specific challenges, both around epistemology and positionality, as they seek to cross academic-practice divides. These are, however, balanced by a significant opportunity of their bridging role: that they might combine the grounded insights of the insider with the confidence and competence to 'talk back' to academic theory, and thus embody a hybrid knowledge valued by both sides. Accordingly, we seek to address two questions: How can academically valid/valued knowledge be produced from reflection on practice within a planning PhD? and How can planning professionals negotiate the specific challenges of positionality raised by becoming an academic researcher?

Challenges in constructing academic knowledge from practice
The first question links to a long-standing practice tradition within academic planning, where researchers have sought out "deliberative practitioners", interested in reflecting on their own practices and debating with academics (Forester, 1999), or to "tell their story" in a focused way both to testify and to inspire others (Clavel, 2010;Krumholz & Clavel, 1994). This tradition has stressed the importance of storytelling (Sandercock, 2003a) to expose and explore in context the choices and dilemmas that professional practitioners face. Notable here is Forester's work, offering a website to share such stories but also a methodology for their collection, 1 and Clavel's construction of an archive on progressive city practices. 2 This work has emphasised the importance of building a repertoire of situated stories to navigate the intricacies of the real world of planning, intricacies that planning theory often fails to address by being too normative or too general (Harrison, 2013). While this tradition values the fine grain of local politics and role of professional practices in city making, it has not asked what changes when this process of reflection on situated professional knowledge is driven not from academics mediating practitioners' experiences (as it seems to do within a practice tradition), but from the practitioners themselves as PhD candidates.
There are specific methodological and ethical challenges for professionals-turning doctoral candidates in mobilising the professional and experiential knowledge 1 3 Producing Planning Knowledge: How Professional PhD Candidates… they have gained, and in translating this into terms admissible within academia, but these are currently seldom discussed. Methodologically, literatures on auto-ethnographies (Ellis et al., 2011), organisational ethnographies (Boyle & Parry, 2007;Ybema et al., 2009), institutional ethnographies (Smith 2006), anthropologies of the state (Sharma & Gupta, 2006), and the vast debates on navigating insider-outsider positions (Headland et al., 1990), provide some guidance on conducting research in organisations "as an insider". The limitation here is that in most cases, the "insider in the institution" 3 is still someone entering an institution as a researcher, not a (former) member of that institution becoming an academic (Hahonou & Martin, 2019). In the rare exceptions where authors are professionals-becoming-academics, their accounts devote much attention to the ethics and politics of writing their research after it has been conducted (Mosse, 2006(Mosse, , 2015Lashaw, 2012). However, they do not provide much detail on the methodology used to build academic knowledge that is partly based on their own professional experience: how, in short, can one create critical distance to reflect on one's own practice? Ethically, the important questions for the doctoral candidate may emerge at a far earlier point in the research process than dissemination: if one's own professional experience is to be used in academic knowledge production, how can this archive be turned into admissible 'data'? How will this impact on institutional and personal relationships that may be ongoing, and how can academic ethical standards for its (retrospective) deployment be met?

Navigating positionality: a specific challenge for practitioners' PhDs
Our second question on the specific challenges of positionality and identification faced by professional candidates, links to debates within the literature on PhD pedagogy. Importantly, this recognises that the PhD process is not simply one of skills acquisition or training, but is also a process of acculturation or (re)identification as the doctoral candidate becomes a member of an academic community. Much of this literature is concerned with improving equity of entry to academia, highlighting the importance of pre-existing cultural capital in doctoral success, and arguing that support for those PhD candidates who diverge from this culture's assumed norms (whether through class, ethnicity, support needs, or other differences) is vital is if academia is to be genuinely inclusive (Cotterall, 2015;Petersen, 2014). This is useful in highlighting that questions of identity can be intimately tied up with what are often seen as merely 'practical' challenges of the PhD, notably writing (Cotterall, 2011(Cotterall, , 2013, a theme we return to below. At its best and most critical, this work also recognises that "doctoral student identity work [is] threaded with political as well as idiosyncratic tensions and unresolved questions" and that "academic identity making is always a chaotic mix of purposive and reactive identifications" (Xu & Grant, 2020: 12). Rethinking this identity work as ongoing and contested-instead of simply a 'trajectory' where the endpoint is the attainment of academic culture-is particularly important in highlighting the ongoing and contradictory stakes that professionals-turning-academics may retain in both elements of their identity. More specific perhaps to these PhD candidates, the loss of social status that becoming a "student" entails (from a position of a City official with its responsibilities, symbolic and practical power and the social recognition attached) might be unsettling for some-especially when sitting in workshops with younger candidates just out of their post-graduate studies. This difficulty was partly mitigated in our cohorts by the fact practitioner PhD candidates were not isolated, but formed part of a group and were (in the South African case) purposefully sought after, allowing for a collective understanding, recognition, and appreciation for the (former or current) professional status of the candidates.
This pedagogical literature also offers practical advice on PhD support informed by this theoretical push to make academia's implicit norms and values explicit. This includes supervisors modelling good practice, building a wider supportive collective environment around the PhD candidate (thereby reducing dependency on the supervisor-supervisee relationship), and providing safe spaces where reflection on these norms is possible (Malfroy, 2005). While these insights are a valuable guide to good practice in doctoral training and development, they do not link the question of the identity transitions PhD candidates undergo to the specific task they face in transforming their own experiential and professional experience into an academic contribution to knowledge.

Our methodology
In an attempt to investigate these questions further, this paper follows a process somewhat akin to that of the PhD candidates we are talking about, in that we critically examine our own professional practice-in this case, of doctoral supervisionin order to build our contribution to knowledge. To provide some methodological rigour to this process, our work is based on four elements. First, our roles in our respective institutions meant we were mentoring a cohort of PhD candidates and were reflecting, formally and informally, on how to best structure a PhD education curriculum at large. At University of Sheffield, Author 2 was the PhD Director first for the Faculty of Social Sciences, and then for the Department of Urban Studies, roles in which he was developing a wider PhD training curriculum, running weekly PhD seminars, and mentoring a number of PhD candidates (some of which supervised by other colleagues). In the School of Architecture and Planning at Wits University, Author 1 was directing a research programme on "Practices of the State in Urban Governance" in South African cities (2014-2018) that involved a cohort of PhD candidates, many of which were purposefully selected by the programme because of their (former) professional practices within the State. In this context, and in response to their specific training requests, Author 1 had developed monthly PhD workshops for the programme, as well as organised, with colleagues, biweekly PhD training sessions for the School at large. In the UK, PhD training has become increasingly formalised, and institutionally supported through the commitment of academics' time to its delivery. This is not the case in South Africa, where setting up regular PhD workshops was done informally, on a voluntary basis and in the context of specific research or exchange programmes.
Second, based on these positions, we co-directed, in partnership between the two Universities, an international programme for doctoral researcher development (2016-9), which provided an opportunity for us to work intensively with a PhD cohort over a series of five fortnight-long exchange visits between our institutions. 4 Although participants were diverse in their backgrounds, a significant number (10 from 25) were coming from professional practice, reflecting in part the importance of these doctoral candidates in planning research more broadly, but also our own research interests in bridging the worlds of practice and academia. Developing and delivering this programme was an opportunity to think in-depth about our supervisory practice, but also to have sustained and collective discussion with participants about moving their projects through key stages of the PhD.
Third, at the end of the programme, our colleague Goran Erfani conducted indepth qualitative interviews with ten of the programme's PhD participants, providing an opportunity for them to reflect on the programme and its impact on their development.
Fourth, we have used our own reflection on these materials, and our mentoring of other professional PhD candidates, 5 to develop a series of 'practice stories' that we present here to capture some of the specific challenges facing professional doctoral candidates in their process of knowledge construction.
An early version of our paper, and the individual stories within it, have been shared with the (current/former) PhD candidates concerned. This was intended not only as a process of verification and ethical good practice, but also to trigger further discussion and explicit reflection on these challenges, thereby further deepening our own understanding how they were experienced, and helping us to discuss possible means to overcome them.
The rest of the paper draws on this material and is divided into four sections. First, we introduce briefly the professional doctoral candidates whose experiences we reflect on. We then address in turn three challenges that emerged as common elements of their progress through their PhDs. These are: How can candidates create critical distance to reflect on their own professional practice? What are the opportunities and limitations in turning professional experience into data? How can candidates be supported when their research produces sensitive or unsettling findings? All three link to our two underlying questions about knowledge production and positionality, and although we address them in the order in which they are likely to emerge as candidates' central concerns, all can (re)surface at any stage in the PhD process.

Professional Candidates as Knowledge Mediators
We begin by briefly introducing the professional doctoral candidates we worked with in producing this paper, prior professional experience being central to both knowledge production and positionality. Table 1 summarises who they are and how the PhD relates to their (previous) professional roles, along with our relationships with them. Our first eight candidates participated within the PhD exchange programme as doctoral researchers; in addition, Sarah (a former PhD student at Sheffield, and a colleague at Wits) was a co-designer of that programme. Although the high concentration of professional candidates within the exchange programme is explained by the background research programme to which the South African candidates were linked, 6 the range of professional roles here would be indicative of student backgrounds in many planning schools with large PhD intakes, and where beginning a doctorate mid-career (in some cases sponsored by a candidate's home government) is commonplace. 7 This diversity of prior experience can directly shape the hybrid knowledge that professionals can produce, but it also adds another layer to the transformations of identity and positionality many researchers undergo through the PhD process.
Many of our candidates had extensive professional experience that contributed positively to their motivation for study, making them more mature than others entering a PhD directly after undergraduate and Masters study. Stepping out (or aside) from an established career in order to write a PhD also involved sacrifices that gave many a clear sense of purpose: "I know what I am looking for, I want to use the PhD to reflect on what I do. I don't have time to waste, it needs to be something meaningful" (Jeni) Beyond this overall commitment, the move towards a PhD for most of our participants corresponded to a "biographical gap" (Siméant, 2001) that offered the possibility of pausing, reflecting and exploring, rather than simply being the "next step" in an academic career. For some, this was the chance to step back from intense and consuming practitioner roles: dealing with hard, sub-optimal choices about altering other people's lives and living conditions, such as Sarah's work in housing provision in poor, violently contested contexts in eThekwini. For others, this move away had been driven by professional roles fundamentally changing (Debjani had been strongly committed to her work within a participatory governance programme in India, only to see this cut short by a policy shift), or their own questioning of their worth (Kate had worked for a legal NGO which had defended rights of the poor against the City of Johannesburg, but felt increasingly frustrated by the antagonistic rather than constructive role court battles placed her in).
Clearly, these biographies matter, in that they point to professional experience, insight and unresolved puzzles that may themselves constitute some of the raw materials of a PhD topic. But beyond this, they are also likely to contain emotional baggage closely tied up with the identity work of the PhD process, as candidates unpack and make sense of their own past professional experience and actions. Supervisors asking why a PhD project has emerged at this point in their careers can help to identify what the PhD's value or role is for each candidate. This does not mean that supervisors can or should become therapists, trauma counsellors or careers advisors-and the line can be thin-but some understanding of these circumstances and trajectories is needed to help the candidate make informed choices, especially where these may be entangled with a quest for meaning or change in their professional practice. Such discussions are usually not resolved at the onset of the process. They continue to deepen as the mentoring relationship develops, and, more practically, may crystallise as discussions around the identification of the PhD topic unfold. Sometimes they even erupt quite late in the PhD process, when candidates are better equipped to deal with the emotions embedded in their professional experience, and build a more theoretical narrative around them.

Creating Critical Distance: negotiating proximity and distance with candidates' professional knowledge
How can candidates create critical distance to reflect on their own professional practice? This distance is shaped by their biographies, but also links to underlying questions about epistemology, and the positionality and identity work that goes on within a PhD. This challenge often emerges early within the doctoral process through the definition of a PhD topic, and is given particular prominence through the choice of an empirical focus and its possible overlap with the candidate's ownarioussional experience. But as well as deciding how far they should directly embrace or separate themselves from this context, candidates also create critical distance by asking researchable questions, by identifying their "academic communities" (the disciplines, fields of study, or particular debates or literatures they wish to engage with through their research), and by working through elements of their professional subjectivity. Here, we address these four aspects of this challenge in turn.

Defining the PhD topic-overlapping, but not too much, with professional experience
For our researchers, choosing a substantive subject area and case study showed a wide continuum of positions. Figure 1 illustrates this, with some candidates directly drawing on first-hand experience (Kate, Neil), whereas others used various strategies to distance themselves from it (Li, Debjani, Sarah). Proximity here may mean directly interrogating one's own practice, challenging it through related academic literature, whereas distancing strategies allow this to be addressed more obliquely: choosing related but different research contexts or thematic areas; or using direct professional experience as one case study or thematic dimension amongst many within a broader study. The displacement or broadening of the gaze allows for analysis at a safer distance, and may meet tactical or essential needs of disconnecting the PhD topic from direct professional experience. While these distancing tactics may also help to avoid sensitive questions about the ethics of data construction and analysis (see Section 4 below), it is important to note that it also has its risks. If reflection on one's own practice was a central motivation for the PhD, this may be diluted, and beyond this, it negates elements of the candidate's own experiential knowledge and privileged access to a professional field, where a unique contribution to knowledge could be made.
Navigating proximity and distance becomes work PhD candidates and their supervisors do jointly-defining an adequate position depends on both. When the research theme or fieldwork site is relatively close to the candidate's professional field, this decision not to disconnect requires other strategies to nurture reflexivity and challenge subjectivity. Questions around how the candidate and her research subjects can be protected (which we return to in Section 4) must also be considered, particularly if she is likely to return to this professional field after the PhD is complete.
Kate was interested in housing policy for marginalised groups in post-apartheid ciƟes. She first considered focusing her PhD on how public housing is allocated to beneficiaries, an under-researched and opaque issue, on which she had no first-hand professional experience. She finally chose to interrogate the effect of liƟgaƟon on policy change, through a court case she had been inƟmately involved in (compelling the City of Johannesburg to provide accommodaƟon to evictees). The choice was made when she reflected on her moƟvaƟons for doing a PhD in the first place: her frustraƟon when engaging with City officials during the case, failing to go beyond legal antagonism in order to build joint pracƟcal poliƟcal responses and contribute to progressive policy-making.
Li was marked by poliƟcal frustraƟon and the feeling of not understanding and not being understood in her professional intervenƟons on managing street trading. But she chose to broaden the focus for her PhD thesis. AdopƟng a Mouffian perspecƟve to consider the potenƟally producƟve dimension of conflict in democracies, she researched how City officials saw and dealt with social contest. The conflict with traders she had experienced, became one case study amongst several others. This allowed her to both respond to her own interrogaƟons and displace her gaze from her own self to a wider range of colleagues, and from street trading to a mulƟplicity of contested areas of municipal intervenƟons.
Debjani chose a topic close to her own intervenƟon as a former government official: analysing the development of decentralised planning intervenƟons in West Bengal. In order to avoid a confusion of roles with programme beneficiaries and with her previous government colleagues, she chose a case study area where she had not worked as a professional. Her familiarity with the West Bengal administraƟon allowed her to secure interviews with elite administrators and poliƟcians, but she had to negoƟate distance here too, politely refusing their requests of assistance in a governance reform programme alongside her doctoral work.
Sarah had leŌ planning pracƟce for academia within South Africa several years before starƟng her PhD at Sheffield University. Her PhD topic built on her experience in housing (as a municipal official and then part of an NGO), interrogaƟng the lack of alignment between the intenƟons of post-apartheid public housing policy and beneficiaries' pracƟces. She drew on her knowledge of housing policy and its insƟtuƟons, on her networks and first-hand experience as a housing official, to inform her research. But both her topic and her fieldwork sites were at a distance from her direct experience.

Fig. 1 Choosing a Topic
Framing a researchable question, keeping the normative at bay: moving from "what should be done?" to "what is happening, how, and why"?
A second element of crafting an appropriate distance towards candidates' professional experience is moving beyond direct, normative engagement with their research topic: What ought to be done? How can better policy, practice, environments be created? How can problems be solved? Such a normative framing to urban research is constitutive of the planning discipline, but is particularly acute amongst professionals reflecting on their own practice. They might expect academic literature to provide objectified (if not objective) guidance, through theories, principles or case studies-and feel frustrated when this literature fails to deliver (Harrison, 2013). Yet, normative questions generally do not open up productive avenues for research: they do not incite observation and critical analysis of social dynamics in the first instance, as the urgency to intervene or improve often blinds the researcher to the complexity of what exists, crushing actual processes under pre-existing normative views.
Darlington, a PhD candidate with a training in economy, had the opportunity of an internship in the City of Johannesburg thanks to his posiƟon in a government-sponsored research center. He was puzzled by the way in which planning decisions, in the sector of water delivery, were not made on raƟonal principles nor backed on staƟsƟcal data. It took some Ɵme to move from a normaƟve view (that decisions should be taken on the basis of sound staƟsƟcs), to an analyƟcal one (interrogaƟng how data was actually produced, circulated and used in the City) -all the more that part of the academic literature in planning and in economics is built on assumpƟons of raƟonalism in decision-making. A detour via actor network theory, which Darlington constructed as his academic "home", allowed him to consolidate his theoreƟcal interrogaƟon, puƫng at the core of his topic an analysis of the relaƟonship between officials and data.
In quest for theoreƟcal framings for her thesis, Sarah felt that the academic literature, predominantly criƟcal of "the state" and its officials, was ignoring the inherent messiness and difficulƟes of their work, blind to their efforts and challenges even when working genuinely towards progressive projects -failing to account for her past experience as a housing official in post-apartheid eThekwini. There, she had been confronted to the urgency of public provision of housing, and the conservaƟve, violent and racist behaviour of some communiƟes surrounding housing projects -whilst planning progressive discourse emphasized the essenƟal democraƟc and social value of "community parƟcipaƟon". To her sense of misrecogniƟon, was added a sense of inƟmidaƟon y theory: who was she to say something back to this established work? Building confidence came gradually -arƟculaƟng her disquiet, finding 'allies' in other literature, and ulƟmately speaking back through her own wriƟng.
Li, a former City official in charge of informal trading in Johannesburg, took part in an academic debate around Ananya Roy's argument that the state was intenƟonally using "informal pracƟces" in its intervenƟons, to protect a degree of flexibility (for pracƟcal, and in Roy's case, for mostly sinister reasons). Li was passionately contesƟng the validity of this view, that she took as a double accusaƟon: that state officials were intenƟonally breaching the rules, and that they were doing so for malevolent moƟves. Whilst she had been witnessing (as an official) and describing (as PhD candidate) pracƟces in the state that could be analysed as "informal" (i.e. in contradicƟon with legislaƟon without being straighƞorwardly "illegal"), she was adamant that these pracƟces were by no means intenƟonal, blinding herself to what the other parƟcipants could see in her own data. A few years later, with more distance and academic experience, she was able to deal with the concept in less emoƟonal, more raƟonalised ways, and published a solid academic paper in an internaƟonal journal (Pernegger 2020a), having, as she says herself, understood "that informal pracƟces were not quite the undesirable pracƟces [she] may have iniƟally thought" (Pernegger 2020b). Our supervisory approach to this challenge has been two-pronged. We begin by recognising that normative questions can lie at the core of the PhD project, rather than dismissing them out of hand, as academia often does. We acknowledge their legitimacy in directing an academic enquiry, and their affective worth in motivating research, but do so with a critical edge that interrogates their place in the PhD journey. Discussion and dialogue can show that they are rarely directly researchable, and can even become obstacles to the task of interrogating existing social processes-a process that was important in the development of Darlington's project (Fig. 2). Deeping analysis, our second task has been to practically assist the candidate in identifying the normative and the descriptive questions-differentiating the empirical from the theoretical, the political from the academic stake. For instance, we would ask candidates 'what is it that puzzles you?', building a research question from this; or ask them to tell a story based on their professional experience that encapsulates such a puzzle. This has worked for some, but is part of process that can take months before a question is formulated clearly by the candidate.

Finding an academic community, in a literature dominated by critical approaches to "the state"
A third element of creating critical distance is to identify a relevant 'academic community' with which the project will engage. Most PhD candidates have anxieties about being insufficiently familiar with the literature to make the 'right' choices here, but for researchers coming from professional practice this challenge may be further complicated by the nature of academic literature on public institutions or on urban policies. This generally adopts a critical perspective emanating from "outside" their professional worlds, and is neither fully invested in nor aware of their internal logics. Often stemming from radical (Marxist or post-modernist) traditions, this literature tends to see the state as either a powerful instrument of domination, that needs to be denounced and challenged, or as a complex institution marked by arbitrariness and messiness, corrupt at worst, inefficient and irrelevant at best (Bénit-Gbaffou forthcoming). Candidates who have spent part of their professional lives 8 working in or for the state can feel directly criticised by this work. More generally, given the difficulties in accessing the internal workings of public institutions, there is a paucity in academic production documenting state practices in cities from the "inside" (ibid.). Literature that studies bureaucracies and the state ethnographically (Hahonou & Martin, 2019) has more echoes with practice-based PhD candidate's own experience; but it does not intersect much with the planning realm, nor the citymaking processes they were confronted with. As Sarah and Li's experiences (Fig. 2) show, the candidate may feel in turn unfairly criticised, stereotyped, mis-or un-recognised: how can one feel part of an academic "community" in such conditions?
Additional confidence is needed to navigate this critical literature, understand and incorporate its contributions, challenge it through analysis drawn from experiential knowledge and insider's perspective, or to appreciate that a degree of mis-recognition might itself point to a research gap.

Dealing with subjectivities in research-epistemology and positionality
Our fourth element for constructing critical distance concerns how candidates reflecting, directly or indirectly, on their own professional experience within their PhDs should treat their professional beliefs, practices and worldviews in light of their new-found position as researchers. This links directly to our overarching question about the specific challenges of positionality faced by professional PhD candidates, and the challenge here is potentially twofold. First, candidates may have heightened expectations of what "science" is, in relation to their personal thoughts and beliefs. Finding a broader intellectual community to question, to explain or to justify their own professional experience, to guide or inspire practical responses to the "wicked problems" they have been confronting in practice, can become an almost existential need. Within this, the danger is that research is idealised as being 'neutral' or 'objective' (either in itself, or that it becomes so through the rigorous implementation of formalised processes) rather than seen as a series of situated attempts and methods to build analytical distance.
Second, candidates have often built a large section of their professional career around sets of beliefs, values or ideologies. These are informed and consolidated through years of professional interventions and can be even more anchored for active (or activist) professionals who invest political or existential meaning in their actions. Deconstructing these beliefs can hold personal risks that go beyond the destabilisation that reflective exercises may trigger in usual academic practice. This can result in practice-based PhD candidates being reluctant to reflect on their own positionality: many hope to "set aside" their own experience, rendering it as invisible as possible, even when the official position and the attached practices the candidate has held are crucial to understanding their PhD's 'puzzle'.
Candidates' understanding of their own position, and the issues it creates, should in theory be a prerequisite for conducting research. While reflections on this are examined in developing the PhD proposal (as part of methodology even more centrally than as part of ethics), articulating positionality and developing reflexivity is extraordinarily difficult for practice-based PhD candidates, and takes an incredible amount of time and processing. Their responses to this challenge are varied, as Fig. 3 shows, and are unevenly productive. Many start by hoping to obliterate their own subjectivity and discard their own knowledge and experience (Nazira's case)an illusion that may be lifted in discussion with candidates. Others may choose to side-step this challenge by choosing topics that are remote from their direct field of intervention, or more subtly (Debjani's case) by decentring their own professional position or perspectives within their analysis. To engage with this professional experience more deeply involves epistemological discussions around what the construction of knowledge is, and the place of the researcher's subjectivity within this. As 1 3

Producing Planning Knowledge: How Professional PhD Candidates…
Kate's experience shows, it often takes substantial progress in writing the PhD, and time for immersion into social science readings where reflexivity is the norm, for candidates to find the confidence to discuss their positionality with adequate distance: avoiding theariouss traps of excessive introspection, meaningless generalities or paralysing self-consciousness.
Our task as supervisors is also caught up within this tension. One the one hand, we need to assist candidates in building a distance towards their practices and position, and in becoming aware of their own subjectivity. Key to this process is helping them to recognise the difference between "bias" as a result of unquestioned and unacknowledged beliefs, and "subjectivity", as a particular stake or position in knowledge construction that one can articulate and defend. On the other, we need to deconstruct any ideas that academia provides an "objective" route to knowledge, while legitimising the place of their subjective experience as a relevant object of analysis in itself, a subject we return to below when we look at transforming experience into data.
Building critical distance on professional practice therefore adds further complications to the usual processes of conceptual reframing most PhD projects undergo as they evolve from a pre-registration idea, to a formally assessed proposal and onwards towards a finished thesis. The identification of an empirical puzzle and academically valued questions to interrogate it is ideally inspired by, but moves beyond, Nazira, a City official in a managerial posiƟon, chose to study the complex governance of the sector she is part of for her PhD. It was iniƟally difficult for her to deal with her own posiƟon. In her PhD proposal, she overlooked the issue unƟl she reached the secƟon of "ethics", where she tentaƟvely wrote: "As a member of the organizaƟon which I am studying, I will also require acknowledging the issue of my "posiƟonality" and to make a conscious endeavour to take the role of the 'third person' and to set aside my experience, knowledge and beliefs during this research". It is only through mulƟple discussions with supervisor, colleagues, and peers, that this vision could be challenged, its impossibility understood by the candidate, but more importantly the value of her subjecƟvity acknowledged.
Debjani's thesis argued that the insufficient mainstreaming of parƟcipatory governance iniƟaƟves in local bureaucracy led to their demise in West Bengal. In the version submiƩed for examinaƟon, reflecƟon on the role and posiƟon of middle-rank bureaucrats who facilitated these iniƟaƟves (the professional posiƟon she herself had occupied) was relaƟvely brief and not really addressed. In her narraƟve, the processes of parƟcipatory planning -such as the producƟon of village maps embodying popular claims -were emphasised over the role of this parƟcular set of actors in guiding them. The need to find distance and set aside her subjecƟve experience perhaps shaped this analyƟcal choice -she was more comfortable in 'looking up' at policy formaƟon and macro-poliƟcal struggle, or 'looking down' at its village-level impacts, than looking at her (and her peers') own pracƟces. This underplayed her own insights into the role this set of actors may have had in making these iniƟaƟves happen, and her analysis of the limitaƟons of their acƟons within the broader bureaucracy.
Kate took Ɵme to formalise the reflexive part of her PhD, that implied taking a criƟcal distance from her former insƟtuƟon, the legal NGO, whilst trying to unpack this NGO's former "enemy", the municipality. She did it in a number of steps: growing confidence in the relevance and solidity of her findings (on how local government policy reform works in response to liƟgaƟon) -allowing for nuanced, balanced and construcƟve criƟcism of the liƟgaƟon process. Another step was the presentaƟon of her research to different audiences, including some of her trusted former colleagues, allowing her to test, debate and eventually consolidate what her PhD quest was about. The posiƟon of the academic researcher that she came to endorse legiƟmately allowed her, albeit someƟmes painfully, to build a third space beyond the antagonisƟc worldview of both NGO and municipality that was brought about by liƟgaƟon. Fig. 3 (Not) Discussing Positionality within the Thesis practical and normative challenges rooted in first-hand practical knowledge. Similarly, choosing an academic literature to engage with is not simply about building an academic identity from scratch (deciding to self-identify as a critical realist, a political ecologist, etc.), but also thinking through what those theoretical positions might say about past professional norms, values and practices that might have been held dear. We return in our conclusions to how these tensions link to the forms of hybrid knowledge the doctorate can produce, but next we investigate the issue of how to transform 'experience' into 'data', a challenge that is particularly complex for those candidates who have chosen to retain a close link between the empirics of their thesis and their past professional roles.

Transforming Experience into Data
If part of the unique opportunity of the professional PhD candidate is that they might use the grounded insights of the insider in the production of knowledge, then a necessary next step in this process is that of turning professional experience into data. This is not a simple act of translation, but rather brings challenges linked to our overall questions about doctoral candidates' positionality and the boundaries of valid academic knowledge. The first challenge is about being able to see, and select from, that professional experience. The second relates to the practicalities and ethics of turning this professional experience into a personal archive, and then deploying it: central here are the boundaries around what is valid and valued within the contemporary academic context.

Seeing Experience as Academic Data
Seeing "what matters"-what empirical material is important and relevant in an academic setting-is a challenge within most PhDs, but particularly difficult to address when this material is itself wrapped up in a candidate's own professional experience. This closeness to the empirical material brings two risks: the risk of being trapped in too much detail, and conversely the risk of not seeing that an incident, event, or insight, or even their own professional routines, reflexes and common sense understandings, may be relevant in their academic analysis.
Over-emphasising detail while losing sight of the broader picture is a common problem within the analysis and writing of all empirically-rich research, but there are at least two additional elements of this challenge specific to professional doctoral candidates. The first is a need to explain the technicality of their job and the minutiae of experiences that affected their practice. What an academic audience need to understand the argument being developed is often subsumed under with details that had a considerable importance as a professional, but might not be needed to prove a point in a PhD. A second element explaining this temptation is the vastness of the personal archive they may be drawing on for the PhD, including email correspondence, reports and other layers of documentations accumulated in what can be years of professional experience. Such a personal archive is a powerful support of the PhD narrative, but it can also be loaded with intense emotional memories, reminding the candidate of intense battles involving local, institutional and personal politics. These battles can only be understood if accurate details are provided around their contexts, their objects of contention (a role, a function, a line in the budget, etc.), and how they unfolded (often requiring a minute chronology of events). To some extent, these battles are at the core of officials' practices and their precise analysis is extremely relevant. But, as students' experiences show (Fig. 4), deciding which to choose, how to narrate them for a non-practitioner audience, and how their plotlines might develop arguments with academic resonance or value are all questions that can be paralysing.
In response to this risk, we have sought to support candidates through a range of supervisory practices. One-shown through Neil and Debjani's stories above-is multiplying the opportunities to present (orally and in writing) research-in-progress, and within these getting the balance right between supportiveness and formality.
Kate, analysing how antagonism played out between NGO and City officials in court, someƟmes was geƫng lost in the details of the court case. She remembered the deep debates the media and official comments would generate in her former team, at key stages of a complex and long court case. The richness of her archive, the emoƟon this archive triggered as a reminder of the intensity of this professional life, led her to write long chapters detailing each step of the legal path. The fear of not being exhausƟve, of simplifying complexity and lacking nuance, put her at risk of losing the broader picture. WriƟng became about learning to let go, to select what was important for her own argument and for academic knowledge (which at Ɵmes may be different from what was important in the case at the Ɵme); or, to beƩer unpack why it was important, what was important in it.
There was a marked contrast between the stories Neil told verbally -about the poliƟcs of a meeƟng, the irony of a situaƟon, the paradoxes of poliƟcal cultures and actual decisions, that he would analyse with devastaƟng finesse, humour and precision -and his wriƟng for academic producƟons, where his habit of wriƟng consultancy reports as well as possibly a fear to "not sound academic" led him to write drily, avoid details, use bullet points that are more descripƟve of an intenƟon than bringing out content. Explaining in supervision the value of the stories, observaƟons and micro-interacƟons he was part of as consultant working with officials, in understanding the poliƟcs of policy-making, helped to some extent. But this has its limits, and it is rather through conversaƟons, recorded interviews, discussions around draŌ texts, that the depth of his experience and thought comes through. However, the limited space usually assigned for wriƟng (a paper, a chapter, a PhD) encourages him to suppress the stories from the text, in ways that oŌen weakens the capacity for framing an argument based on his rich experience as an acƟvist planner.
Neil and Sarah had not directly wriƩen about their experience as planners (consultant, municipal official, NGO employee) in the immediate post-apartheid period. PresenƟng these roles in a classroom proved extraordinarily efficient in verbalising their professional and urban experience. They presented artefacts excavated from their projects, as catalysts enabling them to vividly explain the difficulƟes of professional intervenƟon -maps and photographs to illustrate the poliƟcs of developing a parƟcipatory informal seƩlement layout process, at a Ɵme where technocraƟc and top down method was dominant (Neil); a detailed list of informal seƩlements illustraƟng the challenge of establishing "just" criteria to decide which informal seƩlements should be prioriƟsed (Sarah). Their experience as lecturers, the confidence brought by the legiƟmacy of their posiƟon in the classroom, gave them a crisp understanding of what maƩered in their stories to educate and train future planners -in the situated poliƟcs planners need to engage with in real life situaƟons. I later required the classroom students to conduct recorded interviews with each of them, to capture and deepen such illuminaƟng and grounded tesƟmonies.
Debjani, in a PhD exercise where each had to tell a peer a "sensiƟve" story about the PhD, chose to narrate a conflict she was caught into as an official, with a group of angry male villagers challenging her in a parƟcipatory process. Involving a threat of violence, this moment was also for her an "aha" moment, where she suddenly grasped the gap between officials' and local residents' respecƟve understandings of parƟcipatory democracy. It ended up being such a powerful story that it became the preamble for her PhD: a vivid way of presenƟng the PhD puzzle through a brief but intense snapshot of her lived experience as an official. Only at this late stage of the PhD was this experience formalised and acknowledged by Debjani as a story that was relevant and "counted" as a part of the PhD process. It remained, however, something slightly set aside from the rest of the thesis.

Fig. 4 Articulating Experience as Data
Supportiveness provides a safe space for the candidate to experiment, but a degree of formality, including the time and format constraints of an academic presentation, can push a researcher into selecting relevant data from irrelevant and confusing detail. This can help to identifying what their key argument is, but as Neil's experience shows, some candidates faced by these constraints might revert to familiar writing styles, closing down academic creativity. Alternatively, the candidate might engage with other narratives-academic as well as media analyses of 'their' issue-so as to combine and confront their own understanding with that of others, and hence better identify their own contribution to such debates. A third one-and a response to Kate's experience-is to allow the detailed, technical and minute narrative to be written down, but to restrict this around one specific object or event, creating an account that zooms in on what it is like to be a professional or an official dealing with an issue. Such text can also be left in an undecided format for some time, so that the candidate can explore what a detailed narrative might produce, unload the emotional value attached to it, and release the fear of oversimplifying an account embodying their professional technical expertise. Our experience was that writing this initially as something 'outside' the thesis helped candidates to ensure that this account was not lost, and could become a resource the PhD drew on in different ways. This also meant that candidates weren't simultaneously burdened with capturing empirical richness, and meeting the constraints and requirements of a thesis chapter-a combination that can make the writing process daunting or overwhelming.
The opposite side of our challenge of seeing "what matters" is that PhD candidates often fall into the trap of discarding what is not written down, what is not official, or what relates to emotions, incidents and informal practices, seeing these as irrelevant or illegitimate within a PhD. More difficult still can be recognising and valuing elements of their own situated understanding that are 'not even stories', such as their ability to articulate an institution's internalised or naturalised norms. Here, we have experimented with allowing candidates to express and formulate these stories verbally, to open a space where emotions are acknowledged (but kept under a certain control, as the interaction remains in an academic setting), where the issue of academic legitimacy is marginalised, and where a conversational mode allows for joint exploration. One mode was to invite PhD candidates to give a testimony of their professional experience within a University classroom (Neil and Sarah: Fig. 4). These testimonies were so rich and interesting-legitimised through their pedagogic value, including in the emotions and subjectivities of professionals transmitting their experience-that an in-depth interview with these colleagues was organised as part of the class assignment (following Forester's or Krumholz' & Clavel's models). This double detour, through an oral testimony and a pedagogic rather than research objective, led to the formalisation of professional experience, although requiring the mediation of an interview. Another type of detour towards formalisation, experienced thanks to a colleague specialising in writing support during one of our PhD exchange workshops, was to ask candidates to tell a peer student about a "sensitive issue", something that they found difficult to write about, for about five minutes while the peer actively listened and assisted in unpacking what made this story difficult to write: for Debjani (Fig. 4), this proved a pivotal moment in the production of her PhD.

Producing Planning Knowledge: How Professional PhD Candidates…
The emotions trapped in these experiences, the perceived lack of academic legitimacy in telling such stories, and their (deliberate) excision from professional forms of writing such as policy documents or official reports, all provide powerful impediments for former professionals to construct them as data worthy of analysis. While a phase of verbal formalisation can begin to unlock this experiential knowledge, reading selected social theory can further assist PhD candidates in re-assessing its value, and offer conceptual tools to aid its excavation. Bierschenk and Olivier de Sardan (2014) conceptualisation of state officials' practices being shaped by a multiplicity of conflicting norms (professional, official, practical norms) assisted in demonstrating the value of "practical norms", as departing from the "officials' norms" stemming from policy documents, guidelines, and regulations. So was Lascoumes and Le Gales (2007) , emphasising that policy instruments are constructed objects born out of political and social conflicts and negotiations, rather than mere functional and given tools, and that studying their minute genealogy was crucial to understand the effects they had on society and what they reflected of power relations. For Darlington (Fig. 2), Latour's actor network theory (2005) was used in search for a theoretical backing-giving human and non-human actors and the system of relationships they form, central relevance for the production of knowledge-and opening a space to theorise about technical tools. For Li, Mouffe's concept of agonistic democracy (2013) was not only a step away from an initially fraught engagement with ideas of informality (Fig. 2), but also allowed her to overcome her emotions on the symbolic violence she experienced as an official, and find a frame to analyse the role conflicts played in the making of the city, in terms which are not simply negative. These conceptual tools have been crucial in allowing candidates to "objectify" some of their "incorporated" knowledge. 9 Often it has also been important to find case studies empirically using these conceptual frameworks, to facilitate the dialogical process necessary to bridge the gap between theoretical framings and how they can be mobilised in practice to make sense of, or to excavate, meaningful professional experience (Bourdieu, 1993).

From Experience to Archive
These strategies might help candidates to bring to the surface experiences and practice (including those they take for granted), and to see that these emerging stories might be important and relevant knowledge for the PhD. However, the work of formalisation, objectification and analysis still remains to be done. This is our second challenge: the practicalities and ethics of creating and using this professional experience as an archive.
Constructing this archive, often through auto-ethnography, consists in gathering, classifying and selecting documents pertaining to the candidate's professional experience that are relevant to the PhD topic, and complementing this with other research methods. This includes emails, documents, minutes of meetings, reports in which the candidate was involved, but also the recollections of the candidate, triggered by these artefacts or cast in their memories. Here, it is necessary to stress that memories are constructs but this doesn't imply they should be discarded (as interviewing people on past events is collecting their reconstructed memories as well). The constructed nature of these memories can be signalled within the PhD by presenting them differently or separately from the thesis' main text. We found that candidates were often liberated by realising that they could use different types of writing within the PhD: using boxes within the text, a different font, or dedicating a specific section (such as a preface) to a recollection or personal reflection, assisted them in presenting their stories as one type of data. This clearly differentiated data from its analysis; to mark the distance between these memories and academic reflection on them. These textboxes, which might be extracts from conversations in which they participated, or narratives of events from their professional experience, could then be complemented, crosschecked, debated or even triangulated, as part of the candidate's PhD process.
Interestingly, our candidates often placed more trust in the quotes they have gathered formally in the PhD research process than their own experiential knowledge. Yet that experiential knowledge often permeates the text and implicitly frames its argument. Because they don't deem their experience worthy of being presented directly within the PhD, the evidence that could more convincingly support their point is suppressed, in an act of self-censorship-as was the case for Debjani Debjani, interrogaƟng why an effecƟve parƟcipatory insƟtuƟon in West Bengal was disbanded by government, was arguing that parƟcipaƟon was seen as too much of a challenge to power holders. As an examiner, author A was unconvinced by the evidence provided in the PhD: quotes from officials were rather emphasising the perceived corrupƟon of peƩy poliƟcians to jusƟfy their discard of local parƟcipatory processes. Pressed to consolidate her point, Debjani's own experience eventually jumped out of her memory. "When I was in charge of the project, the Chair of the local council phoned me to complain about my parƟcipatory programme. He told me: 'you are puƫng people on steroids, when we needed homeopathy!' ". This recollecƟon was more convincing than the quotes she collected from officials through formal research interviews. She was encouraged to put this story in the form of a box in the main text, as evidence strengthening her argument.
Crispian wrote a controversial and illuminaƟng book on the structural corrupƟon having consolidated in both a municipality and the ANC regional execuƟve, based on his experience as an official charged with turning around the municipality, and an ANC cadre involved in the party finances (Olver 2017). In order to write the book, he used his daily diary and email correspondence as reminders (of an event, a debate, a chronology), not as a direct source. WanƟng to embark on a PhD on city poliƟcs in South Africa, he needed to write a non-academic book first, to feel free to put his evidence in a wriƩen form without having it saniƟsed by a heavy academic ethical process (in parƟcular the issue of informed consent), whilst carefully corroboraƟng evidence to ensure fair judgements and to avoid lawsuits (or worse). He is then enƟtled, in the PhD, to quote material from his book that might otherwise not be included in the research. This of course raises broader issues about university ethics administraƟon, and the protecƟon it also gives to the powerful against criƟcal thinking. But, Crispian's move might also have had to do with a first aƩempt at wriƟng, downloading the burning issues, before engaging in the differently demanding path of academic wriƟng.
Neil, an acƟvist planning consultant, was part of the design and framing of many progressive policy instruments for local government. He wanted to reflect on this process, unpacking the poliƟcs of policy instrument making, in a Foucauldian perspecƟve. His archive, containing the different iteraƟons of this policy instrument (including the internal debates in the consultant team, their external debates with the City department, and within the municipality) is extremely rich but difficult to use as direct evidence, as most of it was debated in informal email conversaƟons, based on internal draŌ documents, or part of a private consultancy contract. Neil has resorted to use it mostly indirectly. He got permission to quote or publish extracts from some of the archival documents (especially from his fellow team members), but relies mostly on interviews to consolidate evidence and test his argument. Yet, it is at Ɵme extraordinarily frustraƟng to not quote extracts of documents in the text -the materiality of documents having a power on its own (Hull 2012).

Fig. 5
Using a Personal Archive (Fig. 5). This in turn means that mismatches between their argument and (formal) evidence may remain unseen; and strong, personal convictions underlying the argument are left relatively unquestioned. It is through the dialogical work of mentoring that these convictions can be tested, debated and consolidated into an argument: excavating experiential knowledge whose explicit framing and analysis become part of the evidence.
As we have noted, constructing objectified data from personal experience is difficult. Epistemologically, it is bound up with overcoming the fear of lacking distance and being trapped in one's own subjectivity, and going beyond idealised views of an 'objective' research process. Practically it requires experience to be seen as data, and for its status as evidence to be built within the text. Furthermore, it is also complicated ethically. Using material collected outside a formal research process is often tricky, as this can involve former colleagues and institutions, documents not in the public realm, and issues considered sensitive or confidential.
In most cases, the personal archive constructed by the candidate (such as records of email conversations) is used only indirectly as reminders of detail: the chronology of an event, the role other agents played. They support the construction of a narrative, and can assist the search for further evidence by guiding fieldwork interviews and questions. In other cases, the contents of the archive themselves say a lot about the candidate's professional milieu. Hull (2012) and others have stressed how crucial the materiality of bureaucratic documents are to the construction of state authority, legitimacy, and the conduct of officials' practices. Including this material in the PhD, making it the direct object of analysis then becomes crucial to the construction of academic knowledge. Yet, as Crisipian and Neil's experiences show (Fig. 5), this poses complex ethical dilemmas for candidates. Which elements of the archive can be used directly; which could be authorised for publication by their source or the institutions that generated them; which documents would never be authorised for publication by institutions but nevertheless need to be published in order to "tell truth to power"; which ones would if publicised endanger former colleagues, vulnerable people, or themselves? Ad hoc reflection and careful discussions between the candidate, supervisors and colleagues are needed here to address a range of tasks. Why is a specific piece of the archive directly crucial to knowledge; what is the potential damage it could bring; how could it be depersonalised? What are the appropriate tactics of publication which documents can be published, how and where? Alternatively, as Neil's practice shows, they might need to remain indirect evidence that are replaced by other sources that one can legitimately collect as researcher, rather than borrowing directly from one's (former) professional life.

Producing Unsettling Knowledge: dealing with sensitive issues
Linking embedded experiential knowledge to the research project, and thereby allowing it to circulate openly as a contribution to academic knowledge, is often deeply unsettling for the candidate. This is, as illustrated above, partly an epistemological challenge about what counts as data. But bringing professional insights into the academic realm can also expose the "tricks of the trade", the practical norms that contradict the official ones, an institutional culture that values its secrecy. This is likely to impact on the candidate's former colleagues: objectifying former or current colleagues' practices always produces symbolic violence; doing research on elements involving personal relationships is, no matter what is written, a form of betrayal (Lepoutre, 2001). It also raises questions of fear by stepping into confidential or sensitive terrain, publicising (intentionally or otherwise) secrets protected by local government, political parties or other institutions. In countries marked by high levels of violence and fragile democratic institutions, this might involve life-threatening risks.
Of course, these sensitivities are compounded when candidates continue to be employed by an institution that is a subject of research within their PhD, 10 but even if the doctorate ends formal employment, candidates are still connected by numerous professional, political and personal networks to former colleagues (Mosse, 2015). Critically unpacking these people's practices is a threat to the candidate's career and Sarah, during the course of her fieldwork, found evidence that she terms was "a bombshell" about the housing waiƟng list and government pracƟces she was studying. She decided not to follow it through in the PhD, only menƟoning it in a short footnote. We did discuss this in supervision, but at the Ɵme I was not fully aware of its full poliƟcal significance and followed Sarah's judgment. As this issue was slightly aside from her main PhD focus, I didn't push or explore her reasons for hesitancy. In retrospect, this omission was possibly an opportunity lost for both of us. Fuller discussion in supervision could have explored her reasons for making the decision she came to: perhaps building her confidence in making equivalent judgments, and definitely deepening my understanding of her subject area.
Hloniphile is part of dense poliƟcal parƟes' networks and close to personaliƟes influenƟal in government. For her PhD, she chose to interrogate how Black Economic Empowerment played out in Johannesburg policies and poliƟcs. Her heterodox posiƟon on the maƩer put her at odds with the dominant posiƟon of her parƟes-and in someƟmes violent debates via social media, she someƟmes would tell me. Eloquent in public lectures or meeƟngs, she had a wriƟng block for several years. Hloniphile would write short texts, highly theoreƟcal and abstract, detached from empirical evidence. Using poliƟcal philosophy as a shield to limit the risks of being too clearly understood, but also potenƟally as a mask to avoid tackling her own contradicted views on the maƩer. Different aƩempts to unblock her wriƟng from my side had limited success: verbal conversaƟons, creaƟng safe spaces through peer discussions, wriƟng workshops, internaƟonal stays to grant some distance, wriƟng exercises through stories and concrete observaƟons. I also, regularly, suggested a change of topic so that she would feel less exposed. Eventually, she found a new supervisor more aligned to her wriƟng style and philosophical inclinaƟons.
Sogen started to write a PhD on his own experience as a planner in a post-apartheid municipality, while he was sƟll employed there. He had a wriƟng block for a number of reasons, including "not biƟng the hand that feeds" (Moodley 2018), but also, perhaps more existenƟally, because of the difficulƟes of being criƟcal of an insƟtuƟon he has put so much of his own life into building, and of engaging in an academia where radical criƟcal discourse is not nuanced by an understanding of the constraints of working within such insƟtuƟons. AŌer a harsh encounter in one of those academic circles, Sogen suspended the PhD, took a different posiƟon in the City, where he created a research centre assisƟng in research processes conducted on the municipality. Subsequently, he broadened the topic of his PhD, invesƟgaƟng planners' percepƟon of their role in the City, adopƟng a quanƟtaƟve method thus creaƟng more distance, whilst building on his networks and understandings of planners' frustraƟons (Moodley 2019). This allowed him to start a career as an academic. As part of a wriƟng group with fellow pracƟƟoners-academics, he is now geƫng ready, 10 years later, to reflect more directly on his fine-grained experience as a post-apartheid planner. Fig. 6 The Risks of Critique and their Impact on Writing professional networks, in addition to being a difficult process of questioning the status, values and choices they themselves upheld in their previous position. This risk, which can become a serious threat, has sometimes led to freezing the candidate's writing or even thinking abilities, as our examples show (Fig. 6).
Candidates sometimes are caught in tensions where the supervisor has an important advisory role to play. The push to maximise academic value, for example where an insider's view might provide a 'scoop' that changes established understandings of a situation, has to be balanced against the risks such revelations might entail. Supervisors must support students' self-preservation, and can also raise questions about the wider or longer-term effects of publicising sensitive findings: will 'speaking truth to power' be effective, or will it close down future relationships with researchers? Would other, perhaps quieter or more gradual, ways of effecting change be more effective? It is often the PhD candidates themselves who have both a better understanding of the nature and degree of the political risk, and a stronger sense of the mandate they have taken for themselves. The most important task in our experience has been to open a space for discussion, and to offer a safe or conservative path through such dilemmas, even if the candidate ultimately rejects this.
Beyond this, the broader learning from our experiences (Fig. 6) is that supervisors need to be aware of challenges candidates are facing, but should not necessarily expect that these can be easily resolved. Sarah's case is a reminder of the value of prompting a full discussion about the stakes involved. This deepens the supervisor's understanding of the topic, but perhaps more importantly allows joint reflection on the judgment reached. If this particular issue cannot be raised, are there other, less contentious areas where speaking truth to power, or being critical of government practices, might be possible? Candidates' confidence in their decisions about what to research and disseminate can be developed through exploring and articulating their situated ethical and practical judgments that sit behind decisions. Our experience is that the supervisory role here-particularly when the supervisor has limited knowledge of the politics of the context being researched-should be to question, not to judge.
Practically, we sought to support this work through a variety of strategies. One was to create safe spaces that do not immediately involve a public audience, that are sufficiently informal and allow for trial and error, and that gather other PhD candidates having similar professional experience. These were crucial to develop the PhD writing and beyond this, to allow candidates to think critically without losing face. Dialogue with supervisors, exercises that prompt candidates to verbally tell stories that they find difficult to write, or to write in conversation with supervisor, provided other supports. These provide useful tests of how far candidates can safely draw on specific data to develop critique, rather than retreating behind generality or abstraction, but as Hloniphile's case shows, candidates may choose not to engage in such a process. A further strategy was experimenting with alternative types and status of texts that might be used and shared differently. Alongside text 'safe' for public presentation and circulation, alternative versions that are not self-censored may be kept confidentially, or published in different, non-academic platforms, using fiction, or another language, or other masks to "tell truth to power" without taking on personal risk. Finally, despite these various techniques of surfacing issues and containing risk, Sogen's case illustrates that it may only be the passage of a substantial period of time that ultimately gives the researcher the safety and distance to explore their (previous) professional role and context directly as an academic subject.

Conclusions: possibilities and limitations of the doctorate as a space for bridge-building
This paper has explored the potential of the practitioner-turning-academic to provide an important bridging role in knowledge production. The international PhD exchange programme we ran together prompted this exploration, and the experiences of South African PhD candidates, specific in their intensity in the South African post-apartheid moment, have been central to our thinking and reflection. We have used these to map out a series of issues that we hope are, to some extent, generalisable across many professional PhD candidates, while recognising that specific challenges will vary greatly between individuals. Equally, we recognise that the capacity to address these challenges also varies across institutions, and that support in the form of formal PhD programmes and dedicated staff time is often limited outside of so-called 'globally leading' Universities. Accordingly, we have focused on the supervisory relationship as this an integral part of all PhD experiences-can be an important support for this bridge-building in all contexts, regardless of institutional resources.
One hoped-for conclusion of their doctorates is a perfect synergy of the professional and academic knowledge they hold in parallel. This would be a PhD in which the insider knowledge of the candidate has been carefully used to provide additional, and often unique, insights into the complex workings of actually-existing governance practices. At the same time, this PhD would also speak back to theory produced by academics, where the candidate has gained the depth of analysis, and the authorial confidence, in developing the thesis to challenge the sometimes simplified or stereotyped views of professional practice produced by academics researching it as outsiders. Creating this synergy does, however mean addressing a series of challenges specific to the professional doctoral candidate.
Our first underlying question was How can academically valid/valued knowledge be produced from reflection on practice within a planning PhD? Canonical texts in the planning literature (such as Sandercock, 2003b) explicitly value diverse forms of knowledge, and the discipline's practice tradition explores planning practices and sees users' expertise as an essential part of how planning processes operate. But the specific challenges faced by professional doctoral candidate within this field differ from much of this tradition: here the users in the project of understanding planning practice are the planning professionals themselves. In addition, they are both part of the object of the research but also its authors, writers effecting the translation of their own experience into academic knowledge. As we have shown, this means that the critical distance to reflect on this experience has to be actively created at every stage of the research process. This construction of distance allows a considered and effective choice of topics and questions for the thesis, and is vital in ensuring that this professional knowledge can be recognised and appropriately deployed as data within an academic context. We have suggested ways in which mentoring and peerto-peer support can support this building of distance, but it is worth restating that finding allies within the published literature is important in demonstrating the wider value of the insights this can bring. Research which theorises-from whatever position-how practices, norms, and insiders' knowledge actively constitute everyday governance can provide a wider validation of candidates' projects, and underscores the value of the significant efforts they have to make to act as their own interlocutors.
Our second question was How can planning professionals negotiate the specific challenges of positionality raised by becoming an academic researcher? A doctoral education ideally enables a PhD researcher to feel that she is in a process of becoming a full and legitimate member of an academic community, but professional candidates may bring additional baggage with them on this journey. Many will retain an internal, at times schizophrenic, dialogue between their professional and academic identities, perhaps also coupled with an unwillingness to commit fully to what academia values. If the normative desire to change the world (or at least a particular element of governance practice) has been a powerful motivation for the PhD in the first place, then the hybrid knowledge sought for by the candidate may not match criteria of academic innovation or excellence. Explaining the specific case and saying confidently what is to be done may understandably seem like a more important goal or end-point for the thesis. Similarly, fully capitalising on the academic potential of their insider knowledge may be rightly seen as exploitative of former colleagues, or denigrating institutions, policies or practices that they themselves have sincerely valued and embraced. We have aimed to highlight the importance of mentoring conversations in exploring what is at stake for the professional candidate at different stages of the research process, and in constructing safe ways of negotiating the tensions and contradictions this raises, even if this means stepping away from the PhD altogether. Producing potentially more theoretical academic knowledge from the PhD thesis, to have it contribute more broadly to both urban theory and planning education, might then need to be done jointly by the new doctor and their supervisor, as a next phase of a long, complex and rich co-produced process.
Finally, and in addition, we should note the context of the PhD itself shapes the forms of hybrid knowledge that are being produced and valued. The negative side of this is that the doctorate is a space that is limited in a range of ways. Prosaically but also crucially, time and money are at a premium for most candidates: the project has to be brought to a conclusion before either foreclose their capacity to engage with it. Beyond this, the doctorate is more subtly shaped by institutional and disciplinary expectations, and ultimately by being a degree that is examined. All of these constraints mean that as supervisors we should not be surprised when candidates do not have the capacity to explore the possibilities of their unique positionality fully, or feel the pressure to present their research in safer ways that adheres more strongly to tried-and-tested thesis formats. More positively, however, the PhD as a process is akin to an apprenticeship. As such, it provides a space within which some of these tensions and dilemmas can be worked on, while candidates develop the deep skills of analysing and writing about complex empirical contexts (and their own roles within them), and the competence and confidence to speak back to academic theory in its own terms. Whether or not the perfect synergy materialises within the thesis itself, the development of these skills provides the ability to contribute more broadly to urban theory, planning education or to critically-reflective practice. Whatever the particular direction taken, it is this future capacity to play a range of bridging roles that makes the long and complex process of producing doctoral planning knowledge from professional practice worthwhile.