Boundary practices and boundary crossing have been widely used as analytic lenses in research on interdisciplinary collaboration, multi-professional work, and organisational boundary work, where individuals operate across distinct epistemic, institutional, or professional domains (Fisher & Atkinson-Grosjean, 2002; Akkerman & Bakker, 2011). In these contexts, boundaries are conceptualised as potentially productive sites for negotiation, learning, and identity work, and are commonly associated with professional development, transformation, and the reconfiguration of roles.

More recently, this perspective has been taken up in research on teacher education and teacher educator (TE) professional lives, particularly in contexts characterised by disciplinary or epistemic divides. Here, boundary practices are mobilised to explain how TEs navigate competing traditions of knowledge, expertise, and legitimacy, and how such navigation is expected to support professional learning and identity formation (Whitchurch, 2008, 2009; Goos & Bennison, 2018). Across this literature, boundary practices are therefore typically embedded within developmental narratives, in which engagement at boundaries is assumed to culminate—over time—in integration, identity transformation, or settlement within hybrid or “Third Space” configurations (Akkerman & Bakker, 2011; Whitchurch, 2008).

Even when struggle, uncertainty, or liminality are foregrounded, these experiences are generally framed as transitional and oriented toward eventual resolution (Sikko & Grimeland, 2021; Obexer, 2022). As a result, non-belonging is rarely examined as an outcome in its own right, but rather treated as a temporary condition to be worked through within a broader developmental trajectory.

Recent scholarship has begun to question the adequacy of this framing. Marshman and Goos (2025), for example, call for closer examination of cases of “unsuccessful” boundary crossing in mathematics teacher education, while research on TEs’ professional identities documents persistent tensions around recognition, legitimacy, and credibility that do not necessarily dissipate with increased participation or experience (Edwards et al., 2010; Francis et al., 2022). Together, these studies suggest that boundary practices may give rise to professional conditions that remain insufficiently theorised within dominant developmental accounts.

Positioned within this emerging space, the present paper foregrounds TEs’ non-belonging as a distinct and analytically meaningful phenomenon. Rather than approaching boundary practices as pathways toward development or settlement, it examines a trajectory in which sustained engagement at boundaries does not culminate in professional integration, identity consolidation, or hybrid settlement, but instead stabilises as an ongoing experience of non-belonging. Such trajectories sit uneasily within prevailing developmental narratives of boundary practices, which presuppose progression toward coherence or resolution.

Accordingly, the paper addresses the following research question:

How do boundary practices produce and sustain non-belonging in TEs’ professional lives, and why does this condition resist explanation within dominant developmental narratives of boundary practices?

Conceptually, the study draws on relational and process-oriented perspectives on professional identity, which conceptualise identity as constituted through participation, performance, and recognition rather than as a fixed internal attribute (Wenger, 1998; Gee, 2000). Following Darragh’s (2016) distinction between identity-as-performance and identity-as-being, the study allows for the possibility that TEs may enact professional roles and participate extensively in institutional practices without developing a corresponding sense of belonging. From this perspective, belonging is understood as a contingent and socially negotiated condition rather than an automatic outcome of participation.

Within this framework, boundary practices are conceptualised as an enduring professional context rather than a transitional phase. While such practices may enable learning and reconfiguration, they may also unsettle established bases of recognition and professional security (Edwards et al., 2010). When alternative forms of legitimacy fail to stabilise, non-belonging emerges as a condition that cannot be adequately captured through developmental accounts of boundary practices. By centring this condition, the paper seeks to extend existing theorisation by making visible what dominant narratives tend to leave unexplained.

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This study is designed as a longitudinal, theory-driven self-study situated within an ongoing qualitative research programme on boundary practices and professional identity in teacher education. Methodologically, it draws on self-study traditions that conceptualise reflexivity and systematic interrogation of professional experience as analytic resources rather than methodological liabilities (LaBoskey, 2004; Loughran, 2007). The study did not originate as a self-study; instead, it emerged through a multi-stage analytic process in which sustained empirical engagement exposed the limits of existing theoretical frameworks. The research unfolded across three analytically connected phases. In the first phase, the broader programme focused on theorising boundary practices and identity transformation among TEs working across disciplinary and epistemic divides, drawing on established boundary crossing frameworks (Akkerman & Bakker, 2011). In-depth interviews examined how boundary practices were associated with professional learning and identity development within dominant developmental narratives. Within this phase, one interview proved analytically disruptive. The participant—a TE who completed a doctorate in mathematics, later transitioned into a mathematics education department, and had been involved in teacher education practices for over ten years—articulated a persistent sense of non-belonging. This account could not be adequately interpreted through prevailing boundary practice frameworks, which typically presuppose progression toward transformation or hybrid settlement. The second phase involved returning to this case through follow-up interviews conducted over a four-month period, informed by longitudinal qualitative approaches that foreground temporality and continuity in professional experience (Neale, 2019). Analysis during this phase indicated that the durability and internal coherence of this non-belonging trajectory resisted explanation within dominant developmental accounts. This analytic impasse prompted the third phase, in which the study was reconfigured as a self-study. At this stage, the researcher’s own positioning within teacher education practices was analytically foregrounded, allowing the study to examine how non-belonging is constituted, sustained, and rationalised within an ongoing relational context. This orientation aligns with relational and collaborative forms of self-study that treat researcher–participant entanglement as a condition of inquiry rather than a source of distortion (Samaras & Freese, 2006). Data have been generated through longitudinal interviews and reflexive written accounts collected across two four-month periods, spanning approximately eight months to date. The study is ongoing, with further data generation planned as the professional context continues to evolve. Analysis has been iterative and theoretically informed, focusing on patterns of continuity, repetition, and non-resolution rather than predefined developmental outcomes (Finlay, 2002).

Analyses conducted across the project indicate that the focal teacher educator entered mathematics teacher education with a secure and recognition-supported disciplinary identity, consistent with accounts of strong epistemic positioning in prior professional contexts. However, once engaged in boundary practices within mathematics teacher education, the data reveal a trajectory that diverges from the developmental narratives commonly associated with boundary crossing in the literature (e.g., Akkerman & Bakker, 2011; Whitchurch, 2008). Findings from Phase 1 show that boundary engagement does not support progressive identity transformation or hybridisation. Instead, competence—initially functioning as a stable identity anchor—becomes increasingly destabilised. Participation and effort do not accumulate into epistemic security, and the participant reports growing uncertainty regarding legitimacy, evaluative norms, and professional voice. This pattern challenges assumptions in teacher educator research that sustained participation at boundaries leads to expanded or reconfigured professional identities. Data from Phase 2 consolidate this pattern as non-belonging shifts from a problematic experience to a managed and normalised professional condition. Rather than representing a transitional phase, non-belonging is sustained over time, indicating a form of non-arrival at the boundary. In contrast to accounts that frame liminality as productive or temporary (see Obexer, 2022), the analyses suggest that boundary practices may erode prior epistemic authority without enabling the construction of a viable alternative identity position. Taken together, these findings contribute to emerging critiques of boundary practice frameworks that privilege development, coherence, and settlement as default outcomes (Marshman & Goos, 2025). By grounding this critique in longitudinal empirical analysis, the study highlights non-belonging as a durable outcome of boundary engagement in teacher educator contexts. Ongoing analyses continue to clarify how this condition reorganises professional agency and identity claims over time, calling for a more differentiated theoretical treatment of boundary practices in teacher educator research.

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