Public realm ethnography: (Non-)Participation, co-presence and the challenge of situated multiplicity

Against the backdrop of abstract accounts of a variety of processes associated with the ‘end of public space’ (disneyfication, commodification, privatisation, gentrification, securitisation and so on), the last few decades have witnessed a marked growth in ethnographic accounts of the production, meaning and experience of urban public spaces. Methodologically, studying these dimensions of public space ethnographically poses clear challenges for how researchers design and conduct their fieldwork: practically, how can fieldworkers participate in a socio-spatial context typically characterised by ‘situated multiplicity’ (Amin A (2008) Collective culture and urban public space. City 12(1): 5–24) and co-presence with strangers? Moreover, what do researchers do when there are no core group activities, institutional roles or (sub-)cultural practices to participate in? With these questions in mind, I first seek to review the practical fieldwork techniques used by ethnographers interested in studying the urban public realm. I then use this review to synthesise and distil a set of four interlinked fieldwork heuristics for public realm ethnography.

In this paper I seek to complement interrelated efforts to reflect on the substantive content of public space research (Bodnar, 2015), to reify the empirical object of analysis for much public space research (Terzi and Tonnelat, 2016), to theorise spatialised ethnography (Low, 2017), to proffer '[a]n infrastructural approach to the topic of public space' (Latham and Layton, 2019: 1) and to classify public space (Carmona, 2010) with a methodologically oriented review and synthesis of how public space has been (and can be) studied as a socio-spatial object of analysis in and of itself. While 'the general disattention of urban sociologists' to the urban public realm (Lofland, 1989: 453) has gradually diminished over the past three decades, such a concerted focus on the particular methodological features of the data collection methods employed by public realm ethnographers has remained largely absent in the urban studies literature. Borrowing the language of Lofland (1989: 453-454), we have 'bits and pieces' of methodological insight into public realm ethnography scattered across empirical studies, but no coherent review and synthesis of the defining methodological features of ethnographic fieldwork in public realm settings. To this end, the aim of this paper is to address this gap and, specifically, to review, distil and synthesise the shared characteristic features of the data collection methods employed by ethnographers to generate situated and embodied understandings of the urban public realm and of the socio-spatial processes that constitute that realm.
The paper starts with a review of the salient theoretical and methodological literature to make the case for distinguishing between urban ethnographic studies of urban public space (i.e. those concerned explicitly with the social life and social uses of material public spaces as broadly conceived (Lofland, 1989)) and those that are located in urban public space but concerned with a particular social group, process or practice. This argument is situated in relation to various wider theoretical developments that seek, in different ways, to encourage social researchers to rethink, refine and better understand their methodological practice in relation to the particular object of analysis of their research.
On the back of this overview I will draw on the work of Lyn Lofland (1989Lofland ( , 1998 in particular to distinguish between three key concepts ('public space', 'public realm' and 'parochial realm'). I will use this conceptual work as a means to elucidate a particular, and emerging, strand of social research concerned explicitly with the public realm as its primary object of analysis -with the social life of this realm (Jaffe and de Koning, 2016: 55-68), the social uses and meanings of this realm (Darieva et al., 2011: 12-16;Lofland, 1989: 471), and the socio-spatial production of this realm (or with 'the publicisation of public space' as it has been termed (Terzi and Tonnelat, 2016)). My argument is that in attending to the public realm as the focus of their research, ethnographers come up against a dual challenge to participation (and so of conducting 'participant observation' in the conventional sense) and that these challenges invite a rethinking of ethnographic fieldwork approaches in this substantive sub-field.
Building on this conceptual work, I then set about reviewing the most methodologically elaborated public realm ethnographies published to date to assess how ethnographers working in this area have, procedurally, faced up to the challenges of participation I describe. I do this in order to identify commonalities in the particular forms and qualities of research designs repeatedly 'jerry-rigged' (Kim, 2015: 7) by public realm ethnographers. This synthesis provides a basis for proposing a set of four interlinked fieldwork heuristics for public realm ethnography.

Ethnography and the urban public realm
The premise of this paper can be traced back to Ulf Hannerz's (1980: 2) observation that 'the theoretical and methodological resources of the anthropological tradition seem insufficient for urban research'. For Hannerz, much urban ethnographic research can be characterised as being about 'urban villages' (Hannerz, 1980: 5-6). 1 As Hannerz (1980: 5) puts it, these are settings, such as 'ethnic enclaves', that 'may be as similar to the traditional anthropological site as one can find in the city'. Responding to this observed tendency, Hannerz (1980: 5) contends that: To contribute maximally to the ethnographic panorama which is one of the greatest resources of anthropology . anthropologists of the city perhaps ought to give much of their attention to the very opposite of the urban village. (Emphasis added) Lofland (1989: 453) likewise observes that historically urban ethnographers had failed to centre their 'attention . on what is unique to cities: their generation of an area of social life -the public realm -unknown in other settlement forms' (emphasis in original).
This paper can be seen as part of a wider move to start to precisely pay attention, ethnographically, to such settings -ones characterised not by familiarity but by social distance. Specifically, it can be seen as part of a burgeoning literature that seeks to 'spatialise' ethnography. Such work has been advanced most prominently by Setha Low (2017) in her book Spatializing Culture (see also Brudvig, 2014;Dines, 2018;Low and Lawrence-Zu´n˜iga, 2003). Low (2017: 1) uses her own empirical work, in dialogue with the findings of related studies, as a basis to think through and theorise the distinctive qualities and substantive foci of 'the ethnography of space and place'. Building on what has principally been a theoretical and epistemological endeavour to date, this paper pays particular attention to distilling the fieldwork methods deployed by public realm ethnographers and to distinguishing these (terminologically and practically) from those used in more conventional ethnographic settings. Accepting that ethnographic fieldwork is a characteristically 'sprawling' and 'diverse' activity (Van Maanen, 1995: 7), in Hannerz's (1980: 7) terms the aim of this paper is to synthesise a 'more exactly calibrated practical application' of ethnography for studies of urban public realm settings.
A distinct socio-spatial object of analysis: Public realm research This paper can also be seen as part of a broader theoretical endeavour (in particular in urban sociology) to distinguish between modes of ethnographic enquiry according to the type of object of analysis at hand (Desmond, 2014;Jerolmack and Khan, 2017). This conceptual work can itself be seen in part as a response to the increasingly prevalent and for some problematic (Ingold, 2014) use of the term 'ethnographic' as a methodological qualifier. Thus, scholars have sought to more precisely articulate distinctive approaches to ethnography according to the setting and 'analytic lens' of a given piece of research (Jerolmack and Khan, 2017). In this vein, Desmond (2014: 547) has observed that: All matters related to ethnography flow from a decision that originates at the very beginning of the research process -the selection of the basic object of analysis -and yet fieldworkers pay scant attention to this crucial task. For Desmond, three distinctive ethnographic 'objects of analysis' can be discerned: 'a bounded group defined by members' shared social attributes [.,] a location delimited by the boundaries of a particular neighbourhood or the walls of an organisation [., and] processes involving configurations of relations among different actors or institutions' (Desmond, 2014: 547). Desmond (2014: 547) thus distils three types of ethnography: group-based ethnography, place-based ethnography and relational ethnography.
In this paper I seek to extend this categorisation by arguing that in 'place-based' research set in urban public space we can differentiate between 'parochial realm' and 'public realm' ethnographies (after Lofland, 1989Lofland, , 1998. Parochial realm ethnographies are place-based but are at one and the same time group-, practice-or activity-oriented. Public realm ethnographies, by contrast, are much more place-oriented -they take public space as the 'focus rather than the locus' (Hannerz, 1980: 3) of their research. This is not a trivial distinction in my view but one that implies, as I will show later, something not only about the study setting but also about the role of that setting in the analysis.
At this point some important conceptual and definitional work is warranted. The paper adopts a 'topographical' model of public space (Iveson, 2007: 4-17) and is concerned therefore with research conducted in material urban public space (Carmona, 2010) or in the ostensibly publicly accessible space between buildings (Gehl, 2011) in cities. It is important to note, however, that many 'ostensibly public areas of a city -the streets, cafes, bars, and markets of an especially cohesive neighbourhood or the sidewalks and streets of a suburban cul-de-sac, for example -may not be . public . at all' (Lofland, 1989: 455-456). Rather, as Lofland (1989: 455) argues via recourse to the work of Hunter (1985), such areas of the city are parochial realm settings 'characterised by a sense of commonality among acquaintances and neighbours who are involved in interpersonal networks that are located within ''communities'''. In Lofland's (1989: 454) conceptualisation, public realm settings, by contrast, are 'those nonprivate sectors or areas of urban settlements in which individuals in co-presence tend to be personally unknown or only categorically known to one another'. In this respect, the public realm is not coterminous with formally public or ostensibly accessible spaces, but rather is a phenomenon constituted by both the material and social characteristics of a given public space setting.

Two typologies of place-based urban ethnography
Not all forms of situated practice bring strangers into purposeful contact with each other, capable of affective transformation through engagement. The social dynamic of working, living, playing or studying together is quite different from that of strangers rubbing along (or not) in public space or sharing a cultural commons. Co-presence and collaboration are two very different things, and the meaning and affective result of situated practice in each of these sites of 'togetherness' is not the same. (Amin, 2012: 59) For the purposes of this paper the distinction made in the previous section (between the parochial realm and public realm), and echoed by Amin (2012) in the introduction to his chapter on strangers in the city reproduced above, is by no means a moot point. Rather, it underpins a key argument of this paper, elaborated in the next section, that within the wider canon of ethnographies conducted in urban public space we can distinguish between a predominant tradition (parochial realm ethnography) and a more emergent one (public realm ethnography). As Lofland (1989: 473) points out, even though they are public space-based, 'most classic ethnographies of city life . are studies of the parochial realm'. As she puts it, 'it is the world of neighbourhood, of friend and kin networks, and of acquaintances that has been lovingly documented by urban sociologists and anthropologists' (Lofland, 1989: 473). This is a trend that has continued to this day (see Ocejo, 2013) and is even the case for studies nominally concerned with urban public space (e.g. Street Corner Society (Whyte, [1981] 1943), Streetwise (Anderson, 1990), Islands in the Street (Sanchez-Jankowski, 1991) and Sidewalk (Duneier, 1999)). While all of these studies share a titular interest in 'streetlife' (Hubbard and Lyon, 2018), substantively this interest is focused on the parochial realm or on the everyday lives of particular social groups.
In Whyte's ([1981] 1943) work, for instance, the object of analysis is the Norton street gang in Boston (and the behaviour of, and changing relations among, its members). Sanchez-Jankowski (1991) has a similar, albeit comparative, substantive interest in street gangs. With a broader purview, Anderson (1990) is interested in how residential community members experience and practise streetlife in a Philadelphia suburb. Finally, in Duneier's (1999) work the ethnographic object of analysis is a group of sidewalk book vendors in Greenwich Village, New York. Here, then, we have a series of place-based studies oriented around 'communities' of various sizes and degrees of commonality; we have studies that exemplify a broader urban ethnographic trend whereby 'the city and urban space have mainly been treated as background rather than as a focus' (Darieva et al., 2011: 13). Insofar as they can usefully be categorised (given variations in substantive focus and field sites both within and between these studies (Lofland, 1989: 456-457)), such studies can be understood as characteristically parochial realm ethnographies.
Crucially, in parochial realm ethnographies the researcher is able, to varying extents, to participate in core activities constitutive of their chosen setting. They are able to participate, for instance, in working on a stall in Greenwich Village (Duneier, 1999), in street gang rituals (Sanchez-Jankowski, 1991) or in the 'community gatherings' of a residential community in which they too live (Anderson, 1990: ix-x). Over time, 'with growing familiarity and involvement with the subjects', they are able to become an 'observing participant' (Anderson, 2011: 287) in the collective social life of their chosen setting. 2 This is a process that resonates with accounts of wider ethnographic practice, whereby through increasing familiarity with research participants, and the participation in mutual behaviours and activities this familiarity affords, ethnographers 'can learn to take the role of others' (Deegan, 2001: 19) and so generate 'thick' understandings of the constitutive cultural practices of a given lifeworld.
While the studies described above are place-based, therefore, analytically they are largely concerned with the everyday lives of particular social groups in a given (ostensibly public) setting. They share a mutual interest in understanding the practices, behaviours, attitudes, relationships and so on of a particular social group or community. By contrast, in a smaller but growing body of place-based urban ethnographic research that takes definitively public realm settings -and the social lives and uses of those settings -as the focus of research, a much less group-based empirical orientation is evident, accompanied by greater attention to the relationship between the social and spatial dimensions of the setting under study (Kim, 2015;Low, 2017). This emphasis might be understood in Lefebvrian terms as constituting a form of 'spatio-analysis', an approach defined by Soja (1996: 34-35) as 'the analysis, or better, the knowledge (connaissance) of the (social) production of (social) space'. It is this subset of place-oriented public realm ethnographies that I am particularly interested in, and that I will explore in more detail in the remainder of this paper.
The challenges of participation in the public realm As the above discussion suggests, in the parochial realm social interactions are often mediated by at least recognition of some or all of the other actors involved. In the public realm, however, while some users are regular visitors, for many even recognition of others (beyond those you may be with) is likely to be atypical. Rather a 'thin sociality of fleeting encounters' (Bodnar, 2015(Bodnar, : 2097 predominates. This form of sociality has famously been characterised by Simmel as 'a fundamental indifference to distinctions, to instances of unfamiliarity or difference' (Bodnar, 2015(Bodnar, : 2091 and elsewhere by Erving Goffman 'as civil inattention -a lowprofile superficial sociality of co-presence rather than co-mingling' (Bodnar, 2015(Bodnar, : 2091. More recently, Amin (2012: 74) has characterised this form of sociality as 'convivium or living together without the necessity of recognition'. According to these scholars, urban public realm social relations are predominantly detached and distant; at least in the 'everyday' life of these spaces (Jones, 2018) there is a co-presence of users but not a collective sense of purpose or set of mutual practices beyond an amorphous 'collective culture' (Amin, 2008).
Central to the argument of the present paper, Amin (2012: 75) draws out 'two organising principles' of public realm sociality: situated 'multiplicity as the defining urban norm, and co-presence as being on common ground'. It is the central thesis of this paper that these two organising principles not only afford theoretical purchase when it comes to analysing the social potentiality of urban public realm (Amin, 2012: 74), but also that they present particular methodological challenges for conducting participant observation in the public realm. Broadly, we can define participant observation as 'a method in which a researcher takes part in the daily activities, rituals, interactions, and events of a group of people as one of the means of learning the explicit and tacit aspects of their life routines and cultures' (DeWalt and DeWalt, 2011: 1). In this definition we have an emphasis on the one hand of the groupness of the object of analysis, and on the other of the centrality of 'taking part' in a social group's lifeworld. These core tenets of participant observation are, however, problematised in public realm settings characterised by 'variegated space-times of aggregation' (Amin, 2008: 9) -settings where there are likely to be multiple groups, not to mention individuals, co-present at any given time (and using the space over time) -and where social phenomena (activities, rituals, interactions, events, groups and so on) in which to participate are definitively heterogeneous and fleeting. While the public realm may be 'thoroughly social' (Lofland, 1989: 457), that is, the 'social dynamic' of this sociality (Amin, 2012: 60) does not lend itself to sustained mutual participation over time.
Relatedly, at quieter times, or even when public realm settings are empty (e.g. at particular times of the day or when the weather is inclement), the suitability of participant observation is fundamentally called into question. 3 Given these qualities of public realm settings, methodological questions are raised about what activities, or what groups, the ethnographer can or should participate in during their fieldwork? How can a deep understanding of the cultural significance of social activities be generated if practitioners are transient and the activities fleeting? How can a fieldworker meaningfully participate in indifference or being alone in public (Lofland, 1998: 88)?
With these socio-spatial features of public realm settings in mind, I argue that the suitability of participant observation (understood as a data collection method in which 'participating . in people's daily lives for an extended period of time' (Hammersley and Atkinson, 2007: 3) is a defining feature) to researching such settings can be called into question on two main counts that derive from the two 'organising principles' of urban public space identified by Amin (2012). First, the characteristic 'situated multiplicity' of the urban public realm -'the thrown togetherness of bodies, mass and matter, and of many uses and needs in a shared physical space' (Amin, 2008: 8) -renders immersion and meaningful participation in the social life of the public realm as broadly conceived implausible. Second, even if a stable and immersive object of analysis in such studies could be construed, the researcher is still left with the question of how to participate (both when there are many others co-present and when there are none). In contrast to other urban ethnographic objects of analysis -for example, the workplace, the school or a sub-cultural 'scene' -there is no definitive set of activities to participate in but rather a 'situated multiplicity' (Amin, 2008(Amin, , 2012) of social phenomena (or, at times, their absence).

The practice of public realm ethnography
The practical response taken by public realm ethnographers to the challenge of participation has, I argue, been at odds with the practice of participant observation as conventionally understood. Routinely, I contend, the response of public realm ethnographers has in practice been to seek to supplement 'non-participant observations' (classically distinguished from 'participant observations' by Gold (1958) among others) with the collection of interview data and other sensuous data. This 'primacy of the visual' (Shortell and Brown, 2014: 2), rather than the participatory, in public realm ethnographies should by no means be surprising (Jenks and Neves, 2000: 5-6). Indeed, this can be taken right back to Georg Simmel's ([1907] 1997) work on 'why seeing and being seen is so central to urban culture, and why urban dwellers are early on and often socialised regarding the rules of visual interaction' (Shortell and Brown, 2014: 2). It is also very much evident in the work on behaviour in public of Erving Goffman (1959Goffman ( , 1963Goffman ( , 1971, which uses primarily observational data to argue compellingly for the symbolic qualities of interactions between strangers and which has inspired many scholars since to treat 'life in the public realm [as] . both thoroughly social and sociologically interesting' (Lofland, 1989: 459).
Importantly for this discussion, Michael Burawoy (1991: 2) points out that 'the advantages of participant observation are assumed to lie not just in direct observation of how people act but also how they understand and experience those acts'. Indeed, this juxtaposition of 'what people say they are up to against what they actually do' (Burawoy, 1991: 2) can be seen as a definitively ethnographic endeavour. To this end, as public realm researchers have sought to address a perceived gap in our understanding of how public space is experienced by, and is meaningful to, users (e.g. Jones, 2014: 1;Lofland, 1998: 68;Mitchell, 1996: 130), they have moved away from Goffman's perceived reliance on seeing rather than hearing (Sennett, 2002: 36), and have instead sought to render their research 'more ethnographic' (Wolcott, 1990). Specifically, they have sought to replicate the 'data triangulation' (Denzin, 1978) inherent in participant observation discussed above by supplementing their observational data with interview data collected through conversations with others co-present in the field. As Kim (2015: 14) puts it, '[b]ehavioral studies of people in public space are incomplete without an understanding of the sociopolitical construction of the environment: are people sitting in a location because it is pleasant, or could it be that they are trying to avoid someone, or that it is a tradition, etc.?' Finally, in line with features of sensual ethnographic approaches (e.g. Pink, 2015), public realm ethnographers also purposefully and routinely collect other (nonobservational) sensual data in the course of their fieldwork as a means to more fully capture, analyse and represent the experience of being in that space, as a way to understand its social use and value. As Richardson (2003: 87) puts it of his comparative ethnographic study of being in the market versus being in the plaza in Cartago (Costa Rica), the aim was 'to convey the experiential sense of the market and plaza and to extract from that experiential sense what, in the context of public action, the two places mean'.
To substantiate these claims about the challenges to, and commonalities of, fieldwork in public realm ethnographic research, I will now review the most procedurally detailed accounts of fieldwork conducted by public realm ethnographers. As public realm ethnographies, the works reviewed below are premised on a shared assumption 'that space is socially constructed as well as material and embodied' (Low, 2017: 4) and they have a mutual interest in empirically exploring not only how city centre urban public realm is experienced and rendered meaningful by users, but also how that realm is produced (as public) not only formally (through its design, planning and management, in particular) but also through its everyday use or social practice (de Certeau, 1984). At this point it is worth noting that while there is a growing number of empirical studies of the public realm conducted in the ethnographic tradition, in many of these there is a notable lack, bordering on absence, of attention to the practicalities of the methodological (and, in particular for this paper, fieldwork) approach taken. This is particularly the case in journal articles but also applies to monographs in which the account of fieldwork or research procedures provided is typically restricted to a short section of the book (e.g. Dines, 2012: 15-20;Edgerton, 1979: 211-213;Moretti, 2015: 14-20) but may only be touched on in passing in the wider introduction to the work (e.g. Makagon, 2004: xx-xxi).
In the discussion that follows, therefore, I review the accounts of fieldwork methods provided in the write-ups of four recent public realm ethnographies including one of my own (Degen, 2008;Jones, 2014;Kim, 2015;Low, 2000). Substantively, they concern public realm settings both in the Global North (Degen, 2008;Jones, 2014) and Global South (Kim, 2015;Low, 2000). 4 These geographical variations are important considerations given notions of 'graduated publicness' (Bodnar and Molnar, 2010) and the 'differentiation by function and audience' (Bodnar, 2015(Bodnar, : 2099 between public spaces according to their location (at both the city and global scales). 5 However, regardless of location the broad methodological premise of the paper holds that when we seek to study urban public realm qualitatively we need to pay serious attention to the inherent limits of participant observation.
As is typical in ethnographic research, across the works reviewed here multiple sources of data are collected and analysed. In order to delimit my analysis, therefore, and to focus it on the fieldwork challenges faced in these studies (and the ways these challenges were met), in the review, I attend solely to the constellations of in situ fieldwork conducted, and data collected, for the constituent studies. In the remainder of this section I will first summarise the fieldwork conducted for each of the reviewed studies, as well as the aims of the studies, before seeking to distil their common fieldwork features.
In the earliest study reviewed for this paper, Setha Low (2000: xiii) employs ethnographic methods to, in her own words, 'uncover the cultural and political significance of public space by focusing on the design and meaning of the plaza in a contemporary Latin American city'. For this analysis she collects a range of fieldwork data over the course of a 25-year period in two plazas in San Jose´. Two components of these data are important for the present study: fieldnotes collected through observation and interviews with plaza users and others implicated in the production of space (architects, ministers and so on). Notably, Low (2000: 39) states that '[b]ecause of my concern that participant observation in a public space might not capture all the ongoing activities, I utilised three different observational strategies'. These strategiesdescribed in chronological order -are systematic count-based observations of activities in each plaza by 'sector' (enabling the production of behavioural maps), closer observations to document in more detail activities observed in stage one, and 'hanging out' in the plazas (see also Mattson and Duncombe, 1992: 130-131). By the end of the fieldwork, Low (2000: 41) is socialising with some of the plaza occupants, though most of the verbal data presented in her analysis appear to come from less 'naturally occurring' (Hammersley and Atkinson, 2007: 140) one-off discussions with people approached while using the plazas (Low, 2000: 3-30).
In my own study of the use, management, production and 'value' of public space in the context of its ongoing physical transformation (Jones, 2014), I likewise collected fieldnotes and conducted interviews with a range of public-space users and producers. The study concerned the production of urban public realm in and around London's Southbank Centre, 6 and like Low (2000) I opted to differentiate between different observational typologies (Jones, 2008: 85-87), conducting both 'intensive observations' (writing continuous, highly detailed fieldnotes of social activity observed from a fixed position over a period of 1-3 hours in purposively sampled field locations) and 'depth observations' (more reflexive fieldnotes of particular activities and interactions experienced over extended and perambulatory field visits). Moments of interactive participation during the fieldwork for this study were limited. As such, verbal accounts of attitudes towards, experiences of and meanings attributed to the South Bank as public space by users typically derived from 'intercept interviews' conducted 'cold' with purposively sampled passers-by and, to a much lesser extent, through 'natural' conversations struck up in the field. Degen (2008: 4) also grapples with the issue of participation in her comparative ethnographic study of the ways that urban 'regeneration processes transform the sensory qualities of places' in Castlefield (Manchester) and El Raval (Barcelona). As with Low (2000) and myself (Jones, 2014), Degen (2001: 16) deploys 'ethnographic methods' comprising 'multiple modes of data collection'. Of particular interest, Degen (2001: 19) uses the phrase 'pedestrian participation' to describe her observational practice insofar as she participates 'in the neighbourhoods [. by] taking part in . daily activities such as shopping, resting on benches, sitting in cafes'. This 'participation' accounted for temporal and spatial variations in the use of her field sites and, in an auto-ethnographic vein (Ellis et al., 2011), Degen (2001 compiled an 'ethnographic diary' to record 'the sensuous experiences, the feelings that being in these spaces evoked'. Here, then, Degen deals directly with the 'participation' quandary of public realm research by suggesting that it is overcome by undertaking activities typical of the public spaces in which she is interested. Notably, however, the approach is differentiated from 'participant observation', and 'participation' is construed as engaging in the same practices as co-present others but largely as a detached observer. Finally, in her study of the experience, value and meaning of primarily informal economic activity on the sidewalks of Ho Chi Minh City, Kim (2015: 8) describes how she developed an avowedly urbanist 'method of spatial ethnography that joins together social science research and physical spatial analysis to uncover how sidewalks are actually used and the social processes and meaning of that use'. As in the preceding examples, in terms of ethnographic fieldwork this methodology has direct observation or 'looking' (Kim, 2015: 8) at its heart, but seeks to supplement this with interviews with sidewalk vendors (and also police and ward officials) 'in situ' (Kim, 2015: 15) in order to be able to understand, as well as describe and enumerate, social uses of the sidewalk (Kim, 2015: 87). Notably, as is the case in Low (2000) and Jones (2014) in particular, Kim (2015: 97-99) describes an 'iterative' approach to the fieldwork carried out by her and her research assistants. First, an extensive survey of a selected sidewalk was conducted to map the space before systematic observations of the same sidewalk over fixed periods of time were conducted in order to 'outline . the configuration of . activity happening on the sidewalk' (Kim, 2015: 92) and to develop categories of sidewalk use. These more extensive observations were supplemented with 'an intense microstudy of the hourly changes of one block' (Kim, 2015: 98) in order to better understand how the space was shared over time. Interviews with sidewalk vendors were then conducted 'to learn about the factors that produced the spatial arrangements they [the researchers] recorded the day before' (Kim, 2015: 94). Kim (2015: 95) notes how these interviews were typically short, and that interviewees were approached cold and in situ (Kim, 2015: 94). Finally, Kim (2015: 92) describes how the field researchers 'took photos about the sensorial qualities and experience of sidewalk life: colors, textures, notable spatial arrangements and anecdotes' (emphasis added).
While there are invariably variations in the research designs employed in the studies described above (e.g. Kim (2015) incorporates mapping techniques reflecting the spatial emphasis of her analysis while Degen (2008) compiles an ethnographic diary to reflect her own sensory emphasis), across them attempts to address the challenges of collecting data as a 'participant observer' are clear. In seeking to attend to the situated multiplicity of their respective study settings, each author's capacity to participate in the social life of these spaces is necessarily delimited and they in turn need to develop and deploy alternative and/or supplementary methods to collect their data. Most distinctively, these authors substitute participant observation with a mix of other data collection methods. Rather than collect data through a praxiographic (simultaneously sensory and discursive) engagement in a given social world, therefore, public space researchers are more likely to directly observe social phenomena in public space and explore those social phenomena discursively through interviews conducted on site having 'approached people using public spaces' (Degen, 2001: 17). This temporal disconnect between observations and interviews is necessitated by the transient and heterogeneous composition of 'the public' in a given space. This is not to say that moments of more spontaneous, naturalistic verbal interaction do not take place in the course of public-space fieldwork (cf. Jones, 2014: 160-161;Low, 2000: 21-22) but rather that in order to interpret the significance of what has been observed (Kim, 2015: 14), public space researchers need to rely heavily on a distinctive set of interview data with users of public space rather than on everyday verbal exchanges conducted over the course of participating in a given social practice or group (e.g. Low, 2000: 16-17). This describes not only more of a disconnect between the collection of observed and interview data in public realm ethnography (compared with other ethnographic objects of analysis), but also more of a disconnect between who is observed and who is interviewed (given the heterogeneous and transient make-up of users of public space).
Public realm researchers calibrate their methodological practice in the face of the participation challenge in another important way, however. Thus, as the capacity to participate in group practices and, crucially, to participate in and instigate naturalistic discussions around these practices diminishes, there is a tendency among public realm researchers to extend their collection of data both outward (to include a wide array of sensory data (see Bodnar, 2015Bodnar, : 2102) and inward (with an emphasis on reflexivity (esp. Carabelli, 2014)). 7 Of the works discussed in detail the multi-sensory emphasis is most pronounced in Degen (2008) but it also permeates the analysis presented by Low (2000), Kim (2015) and myself (Jones, 2014). Perhaps owing to the researchers' reduced capacity to collect data through mutual participation in social group practices, all of the works reviewed for this paper are also markedly reflexive -repeatedly drawing on fieldnotes that articulate the researchers' experiences of being in public and how this is shaped by the social and spatial aspects of the setting at that moment. Related to these sensory and reflexive emphases, public realm researchers routinely attend to the visual and spatial dimensions of their field sites (e.g. through the use of photographs or mapping in their analysis (esp. Kim, 2015: 91-99)). They are interested in how, for instance, urban morphology shapes (and the experience of that morphology is shaped by) social practices and appropriations.

Heuristics for conducting public realm ethnography
Importantly, out of the review and analysis presented above we can identify some common methodological traits adopted by public realm ethnographers in response to the participation challenge in public realm settings that motivates this paper. These traits can be summarised as an interlinked set of heuristics for conducting public realm ethnography: first, public realm ethnographies are characterised by a primacy of the visual and, as such, non-participant observational data collection is a core feature; the collection of observational data tends, however, to be sequential and 'iterative' (Kim, 2015: 98), characterised by a shift from more extensive and systematic observations of pre-determined sectors of a given setting (which are collected from a fixed location over a fixed duration), through focused and directed observations of particular social phenomena (e.g. activities or events) that have emerged as being of interest in the initial observations, to more flexible, itinerant and multi-sensory cognition of the experience of being in the public realm; in this respect, the collection of observational (and other non-reactive sensory) data in public realm fieldwork tends to be conducted through a combination of systematic non-participant observation of researcher-defined spatial zones constituent of the wider setting, intensive observation of particular social phenomena and an itinerant mode of ethnographic 'being' (Richardson, 2003) or 'hanging out' (Low, 2000: 41;Mattson and Duncombe, 1992: 130-131) in public space. To differentiate it from 'participant observation', this latter fieldwork mode might be termed (co-)present cognition 8 -data are collected (using fieldnotes and field diaries) through an emphasis on physical (co-)presence in the field and through the markedly reflexive, multi-sensorial and perambulatory recording of data; 9 finally, in order to approximate the inherent triangulation of verbal and nonverbal data afforded through participant observation, public realm ethnographers supplement their observational data with the collection of typically short 'intercept interviews' (Jones, 2014: 23) with others co-present in the public realm setting. These interviews are informed by the researcher's observational data and interviewees are typically approached 'cold'.
While, owing to the marginalisation of accounts of field experiences relative to the reporting of findings long associated with ethnographic writing (Richardson, 1988: 203), the review above focuses only on a more methodologically-elaborated subset of public realm ethnographies, the salience of the fieldwork commonalities drawn out in the review is evident in the wider literature. Thus, an emphasis on non-participant (as opposed to participant) observational data is a recurrent feature of public realm ethnography (e.g. Edgerton, 1979: 76-97;Holland et al., 2007: 5;Makagon, 2004;Mattson and Duncombe, 1992: 131), as is an attentiveness to the wider sensual experience of public space (e.g. O' Keeffe, 2015;Rhys-Taylor, 2017), and a purposeful emphasis on supplementing observational data with interview data as a means to 'juxtapose' stories, events, encounters and key informant insights (Moretti, 2015: 17;Watson and Studdert, 2006: 4-5) in the vein of participant observation (Burawoy, 1991: 2).

Conclusion
In the context of a rapidly growing body of urban studies literature concerned with public space (Bodnar, 2015), and a burgeoning subset of this work concerned with integrating 'the social production of the built environment with the daily routines and ceremonial rituals of the cultural realm and the phenomenological experience of individuals' (Low, 2000: 36), this paper sets out a methodological response to the important call for ethnographers to be more attentive to the 'object of analysis' of their studies (Desmond, 2014). The paper argues that in social scientific research conducted in urban public space settings we can broadly distinguish between studies concerned with communities inhabiting such spaces (with the parochial realm) and studies concerned with (the production of) the public realm in and of itself. 10 This distinction has important methodological ramifications -if our concern is with the production of public realm, and with public realm as a site of situated multiplicity and co-presence (Amin, 2008(Amin, , 2012, then as ethnographers our capacity to meaningfully participate in our study settings is challenged. Indeed, it is precisely on these grounds that public space ethnographies have been critiqued (e.g. Feldman's (2006: 149) critique of what he characterises as ' Makagon's (2004) predominantly nondialogical, impressionistic observational method').
Public realm ethnography, as with urban ethnography more broadly (Jenks and Neves, 2000: 11), can be understood as a 'mixed-method' approach -indeed for some, 'ethnography' has become a byword for mixed-methods (Mitchell, 2011: 55). And as with other modes, what makes the approach 'ethnographic' is its emphasis on exploring social phenomena in a way that emphasises a naturalistic disposition. 11 Unlike in traditional ethnographic settings, however, participant observation is not, and cannot be, the primary mode of data collection in public realm research because as a site of situated multiplicity and co-presence (Amin, 2008(Amin, , 2012 this realm is intrinsically unsuited to the collection of data through participation in social group practices. As a result, public realm ethnographers have practically (and consistently) 'jerry-rigged' (Kim, 2015: 7) a repertoire of field research methods (Bailey, 2018) 12 to mitigate these participatory challenges. These include greater reliance on intercept interview data to interpret directly observed behaviours and practices. They also include a range of observational techniques that span direct systematic observations of public space, focused observations of particular social phenomena co-located or unfolding in public space, and what I term '(co-)present cognition'. By drawing attention to the participatory challenge in public realm research and synthesising the practical approaches taken by public realm ethnographers, this paper hopefully serves as a starting point for articulating how a more exactly calibrated ethnographic methodology for studying the production and everyday life of this distinctly urban realm might be characterised and designed.

Funding
The author received no financial support for the research, authorship, and/or publication of this article.

ORCID iD
Alasdair Jones https://orcid.org/0000-0002-4933-4023 Notes 1. For example, the readings reproduced in Ocejo (2013). 2. For a classic example of observant participation see Whyte's ([1981] 1943: 14-25) account of taking part in a bowling competition with his research participants (and his analysis of the insights this participation gave him into the group norms, hierarchies, relations and so on). 3. Low (2000: 16) sums this challenge up neatly, recording in some fieldnotes from Plaza de la Cultura how '[t]here is so little activity that it is hard to be a participant observer'. 4. Low's (2000) field sites are two plazas (Parque Central and Plaza de la Cultura) in downtown San Jose´, Costa Rica; Degen's (2008) field sites are Castlefield (Manchester) and Raval (Barcelona); Jones's (2014) field site is London's South Bank; and Kim's (2015) field sites are the sidewalks of two neighbouring neighbourhoods in Ho Chi Minh City. 5. See Dines (2018) for a discussion of 'contextual diversity' in public realm research. 6. The Southbank Centre is the UK's largest arts centre occupying a 17-acre site on the south bank of the River Thames in central London. 7. For Carabelli (2014: 206) the collection of field data through walking can in fact be seen 'as an epistemological practice, which supports reflexive engagement with the fieldwork'. 8. 'Cognition' is defined as 'the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses' (Oxford Living Dictionaries: English. Oxford University Press. Available at: https://en.oxforddictionaries.com/defini tion/cognition, accessed 27 August 2018). 9. Notably walking and sensory methodology are two prominent features of emerging work on imaginative and creative ethnographic approaches (Elliott and Culhane, 2017). 10. There is no unambiguous distinction between these sets of studies but rather, just as urban realms can be placed on a conceptual continuum (Lofland, 1998: 14-15), so there is of course between-study and withinstudy variation in the 'object of analysis' in public space research (between public space and community/ies in public space). 11. As a point of comparison, see Kusenbach's (2003) account of the 'go-along interview' as an ethnographic research tool. 12. As public life becomes ever more online and virtual (Bodnar, 2015(Bodnar, : 2094 we can envision the collection of social media and other digital data being incorporated into this mix.