The idea that professional development (PD) can improve the quality of instruction is generally accepted and about 90 per cent of teachers internationally participate in professional development (PD) annually (Kirsten, 2020). Billions have been invested in research intended to find out how to design successful PD (e.g., Boulay et al., 2018), which has resulted in a marked increase in the number of studies of teacher PD programs (e.g., Sims et al., 2023). While a lot has been learned from this literature, fundamental questions remain. In particular, it has been argued that a lot of the PD literature has focused on effects and/or core critical features (i.e. what works), and neglected the importance of better understanding the processes and mechanisms of how teachers change during participation in these programs (Asterhan & Lefstein, 2023; Kennedy, 2016).

The aim of this study is to contribute to the above call for research by investigating what and how teachers learn (i.e. the learning mechanisms) when participating in a professional development program. Our case is Quality Teaching Rounds (QTR), a thoroughly tested Australian PD program which in several randomized control trials has been shown to enhance teaching practices and boost student achievement (e.g., Gore et al., 2017; 2021). Since 2023, four Swedish schools have participated in a research project introducing QTR and from which data for this study is collected. QTR is based on teachers in groups of four observing and discussing each other's lessons with the Quality Teaching Model (QTM): To support the observations and the following discussions, teachers have access to the Classroom Practice Guide (CPG), which describes the QTM in detail and provides question sets and practice suggestions. Rather than prescribing a specific teaching method, the model is designed to support teachers to analyze and refine their practices.

In this study, we position the CPG as a boundary object and teacher learning in QTR as learning at the boundaries. Starting with boundary objects, they serve as shared reference points for different groups while remaining adaptable to local needs (Bowker & Griesemer, 1996; Star & Griesemer, 1989). In education, they may, for example, help teachers collaborate and refine teaching strategies (Akkerman & Bakker, 2011; Wenger, 1998). For example, the CPG may support teachers to bridge theory (i.e. the QTM) and practice (i.e. classroom instruction).  However, boundary objects are not a universal solution—their effectiveness depends on how they are adapted over time and to different contexts (Carlile, 2001; 2002). Moreover, we view teacher learning in QTR as learning at the boundaries. Akkerman and Bakker (2011) suggest four learning mechanisms when learning at the boundaries: identification, coordination, reflection, and transformation. Reciprocal identification concerns when individuals define or redefine how intersecting practices either differ (othering) or meaningfully coexist. Cooordination involves communicative links between different actors to optimize efficiency and establish reliable routines. Reflection relates to when individuals consider differing perspectives, leading to a deeper understanding of their own practices. Finally, transformation occurs when changes emerge within existing practices or new, intermediate practices develop, often addressing shared issues and generating new ideas (Akkerman & Bakker, 2011).

This study seeks to contribute to the research on professional development by making use of qualitative methodology. In this study, all teachers were chosen based on the following preconditions: they were taking part in QTR rounds and volunteered to take part in pre/pos/post-post interviews. The data consists of semistructured interviews with seven teachers from four schools. Five of the teachers work at primary schools and two of the teachers work at upper secondary schools. The teachers have extensive working experience. To examine in what ways teachers learn when participating in QTR and in what way the QTM functions as a boundary object, each teacher was interviewed at three occasions, once before they took part in the QTR, and twice after their participation in the QTR (pre/post/post-post data), a total of 21 interviews. During the interviews, the teachers were asked questions about their views on teaching, for example what they expect teachers or pupils to be doing in a classroom that has high quality teaching, or what types of assignments they expect pupils to be working with in order for the teaching to be of high quality standards. Also, the teachers were asked questions about collegial collaboration at their schools. All interviews were recorded and transcribed verbatim. We have conducted a preliminary two-step analysis, first examining how QTM functions as a boundary object and then exploring the learning mechanisms related to QTM using a framework from Akkerman and Bakker (2011). The transcripts were examined in detail to detect recurring patterns within the data. These patterns were then compared and systematically categorized into themes in line with the study’s overarching research objective (Fejes & Thornberg, 2019). The abductive approach entailed an iterative process, continuously moving between the collected data and theoretical insights (Rinehart & Carlson, 2021). The data were structured by recognizing both common trends and distinct findings relevant to the study’s main goals (Brinkmann & Kvale, 2015), ensuring a transparent and well-founded analysis. Thus, the themes were “actively produced by the researchers through their systematic engagement with, and all they bring to, the dataset” (Braun & Clarke, 2022). The themes were not ranked by significance, and illustrative quotes from participants were selected based on their frequency in the dataset. Throughout the process, the analysis remained closely connected to the study’s objectives, research questions, and theoretical framework (Brinkmann & Kvale, 2015).

The QTR has provided a structured framework for observing and reflecting on teaching. Teachers report developing a common vocabulary to discuss teaching quality (Carlile, 2002), frequently using terms like "higher-order thinking" and "student agency." QTR has also established a shared reference framework, helping teachers analyze teaching more uniformly. Collegial discussions have become more structured, shifting focus from student behavior to teaching content and effectiveness. Thus, the PD model of QTR enables groups to work together and the CPG, as a boundary object is an artifact that is negotiated in collegial discussions and that articulates meaning (Star & Griesamer, 1989) which thus provides a common language for teachers, which is much sought for Teachers highlight how the Classroom Practice Guide within QTR has supported lesson planning and evaluation. As a boundary object, the guide offers flexibility (Bowker & Star, 1999), allowing adaptation while maintaining a common framework for assessing teaching quality. A key theme is the transformation of teachers’ views on student activity and engagement. They now emphasize participation, higher-order thinking, and classroom discussions, encouraging students to verbalize their thoughts. Thus, a transformation is seen, leading to new, intermediate practices (Akkerman & Bakker, 2011) and increased awareness of active versus passive learning (Tsui & Law, 2007). However, challenges remain. Some teachers struggle with unclear translations of key concepts and interpreting certain criteria, indicating that boundary objects are often culturally conditioned (Carlile, 2002) and require ongoing refinement (Nicolini, Mengis, & Swan, 2012). Practical constraints, such as a shortage of substitute teachers, hinder efficient coordination, and while QTR improves lesson planning, maintaining changes is difficult without organizational support, such as time for collegial discussions. This underscores the tension between ideal implementation and real-world constraints (Akkerman & Bakker, 2011).

Akkerman, S. F., & Bakker, A. (2011). Boundary crossing and boundary objects. Review of Educational Research, 81(2), 132-169. Asterhan, C. S., & Lefstein, A. (2023). The search for evidence-based features of effective teacher professional development: a critical analysis of the literature. Professional Development in Education, 1-1. Boulay B., Goodson B., Olsen R., McCormick R., Darrow C., Frye M., Gan K., Harvill E., Sarna M. (2018). The Investing in Innovation Fund: Summary of 67 evaluations. Final report (NCEE 2018-4013). National Center for Education Evaluation and Regional Assistance. Bowker, G. C., & Star, S. L. (1999). Sorting things out: Classification and its consequences. MIT Press. Braun, V. & Clarke, V. (2022). Thematic Analysis. SAGE. Brinkmann, S. & Kvale, S. (2015) Interviews: Learning the Craft of Qualitative Research Interviewing. 3rd Edition, Sage Publications. Carlile, P. R. (2002). A pragmatic view of knowledge and boundaries. Organization Science, 13(4), 442-455. Edwards, A. (2010). Being an expert professional practitioner: The relational turn in expertise. Springer. Engeström, Y. (2001). Expansive learning at work. Journal of Education and Work, 14(1), 133-156. Gore, J. M., Miller, A., Fray, L., Harris, J., & Prieto, E. (2021). Improving student achievement through professional development: Results from a randomised controlled trial of Quality Teaching Rounds. Teaching and Teacher Education, 101, Kennedy, M. M. (2016). "How Does Professional Development Improve Teaching?" Review of Educational Research, 86(4), 945–980 Nicolini, D., Mengis, J., & Swan, J. (2012). Understanding the role of objects in cross-disciplinary collaboration. Organization Science, 23(3), 612-629. Sims, S., Fletcher-Wood, H., O’Mara-Eves, A., Cottingham, S., Stansfield, C., Goodrich, J., & Anders, J. (2023). Effective teacher professional development: New theory and a meta-analytic test. Review of Educational Research, 00346543231217480 Star, S. L., & Griesemer, J. R. (1989). Institutional ecology, `translations’ and boundary objects. Social Studies of Science, 19(3), 387-420. Tsui, A. B. M., & Law, D. Y. K. (2007). Learning as boundary-crossing in school-university collaboration. Teaching and Teacher Education, 23(8), 1289-1301. Wenger, E. (1998). Communities of practice: Learning, meaning, and identity. Cambridge University Press.