Several decades of teacher effectiveness research show clear correlations between teachers' ability to adapt instruction to students' needs and students' learning gains. For teachers to develop this complex adaptive ability, however, at least 15 years of professional experience is often required (van den Hurk et al, 2016). At the same time, societal developments in the 21st century have resulted in teachers today encountering a highly diverging population of pupils, wherefore attempts to accelerate teachers' ability to adapt instruction to students' needs are considered urgent (Ibid.).

This study was carried out in Sweden, where operational responsibility for students’ schooling rests at the municipal level. Overall regulation is provided by the National Agency for Education (NAE) via curricula, grading criteria, and national tests, but local school professionals enjoy a high degree of freedom regarding the design of instruction and assessment. The last 15 years, however, the state has increasingly taken control of the substantive and methodological focus of instructional improvement efforts, by providing state grants to municipalities committing to work with national-scale teacher professional development (PD) programs in content areas designated by the state as particularly important. The most extensive efforts have been directed at mathematics and literacy instruction, with the expressed goal to strengthen Swedish teachers' ability to adapt instruction to students' varying needs. Within the national PD programs, teachers work according to a fixed cyclical model including text reading, testing given methods in the classroom, and discussing in 'collegial learning groups'. As these programs are linked to extra funding, their content and associated working methods have come to occupy a large part of Swedish teachers’ annually allocated PD time.

One of few research studies on the national programs' impact on students' results shows that the program aimed at mathematics instruction had a small but statistically significant impact on teachers' instructional practices but no effect for student achievement (Lindvall et al., 2022). Moreover, neither national grade statistics nor internationally comparative knowledge measurements show any increase in students' knowledge results to date (Skolverket, 2023). Thus, it can be questioned whether such efforts, given their enormous financial cost, are effective in raising teachers' ability to adapt instruction to students' needs. There is also concern that the dense flow of general solutions provided from school authorities risks reducing rather than strengthening teachers' agency and ability to analyse the needs of their own student base (Engström, 2022; Jahnke & Hirsh, 2021).

This study stems from a three-year R&D collaboration - involving three researchers and 170 teachers - initiated as a reaction to the development described above, where general prescriptions for instructional improvement are served top-down from school authorities. The collaboration’s overall design is grounded in the activity theoretical frameworks of Expansive learning and Transformative Agency by Double Stimulation (Engeström & Sannino, 2010; Sannino 2022; Vygotsky, 1997/1931). Since expansive learning implies that the collaboration taking place is about jointly learning ‘something not yet there’, the researchers' role is not to share a predetermined method for the participants to implement. Instead, double stimulation is regarded as a core mechanism to guide and strengthen the transformative agency of the actors working with the changes in practice. Hence, the role of researchers is to provide stimuli that evoke and contribute to maintaining a transformation process led and owned by the practitioners.

This study aims to contribute knowledge about teachers’ professional development through:

• Presenting a theory of action for teachers’ use of assessment information for needs-based instructional improvement that recognizes multidimensional professional knowledge and stimulates agentive action.
• Exploring how that theory is put into practice by teachers and what effects it potentially entails regarding students' and teachers' knowledge development.

During the R&D collaboration (August 2021-May 2024), researchers worked with the teachers (representing different school forms and subjects) to strengthen their professional agency and achieve instructional improvement rooted in the needs of actual students, ascertained in assessment information. The theory of action is to be understood as an overall stimulus containing a series of second stimuli – ‘thinking tools’ – designed to enable the teachers to redefine the challenging task of instructional improvement and take volitional action through instructional interventions. The theory of action intertwines ideas from Gee's sociocultural understanding of Opportunity to Learn/OTL (2008), van Manen's epistemology of reflective practice and pedagogical tact (1991; 1995), an Aristotelian conceptualisation of multidimensional professional knowledge (Johannesson, 1999), Biggs’ (1996) theory of constructive alignment, and Harlen's conceptualization of the relationship between formative and summative assessment (2012). Work has taken place in two arenas: 1) at regularly occurring two-day dialogue conferences (program level), and 2) continuously by teachers in practice at the home schools. Dialogue conferences have offered research input, thinking tools, workshops, cross-group presentations of ongoing/completed casework, individual and dialogic reflections on intervention processes and experiential professional learning, and feedback from researchers to participants/between participants. During the collaboration, teachers have (cyclically): • Selected 1-3 case students each at the home school. • Defined specific learning needs of case students based on analysis of assessment information relative well-defined aspects of school subjects and curricular assessment criteria. • Participated in monthly collaborative workshop-and-learning sessions at the home schools, for joint analyses and formation/refinement of instructional interventions with assumed potential to meet case-students’ learning needs. • Implemented, evaluated, and documented case-students’ responses to the interventions. • Meta-reflected on 1) various spillover effects of the casework, and 2) individual and collective professional learning. • Conducted cross-group presentations of ongoing/completed casework. • Documented completed case work, including research-informed and experiential professional learning meta-reflections, in coherent case reports. Data processed for this study comes from: • Two questionnaires with Likert scale and open-ended questions answered by all teachers. • In-depth interviews with 12 teachers. • Case reports written by 102 teachers after completed cases. Data was analysed using directed qualitative content analysis (Hsieh & Shannon, 2005) to discern 1) which assessment information teachers use and how, 2) if and how the provided stimuli has evoked agentive action in teachers’ casework, 3) signs of performance improvements in the case students, and 4) expressions of experiential professional learning.

Results indicate that the theory of action has been highly appropriated by the teachers, enabling them to 'translate' formal (test-based) and informal (classroom-interaction-based) assessment information into clearly defined learning needs - a step in the instructional improvement process that many had previously paid little attention to. Regardless of school form, teachers agree that such translation contributes powerfully to shifting focus from the student's shortcomings to instruction as decisive for students’ opportunity to learn, and that the translation enables greater precision in the planning of effective instructional interventions. Most teachers report that provided thinking tools have contributed to the articulation of a crucial part of professional knowledge – that which, with van Manen (1995), denotes pedagogical tact - which otherwise often remains unarticulated. In interviews and case reports, teachers describe how they intuitively have always known that to effectively address learning needs, tact must be active together with the more scientific and rational forms of professional knowledge. Clearly, it empowers the teachers, that the theory of action used here assigns pedagogical tact a value and provides conceptual tools to verbalize it. Teachers report that they have become increasingly confident in taking as a starting point their own and their colleagues' multidimensional knowledge in planning needs-based instruction. Additionally, they unanimously report that the case methodology, i.e., to intervene and learn with starting point in specific students, is highly effective for achieving analytic concretion. In nearly all student cases completed so far, knowledge development (often measured through tests) relative to curricular goals is confirmed. Certainly, causal relationships cannot be established with certainty in a project such as this, but it is reasonable to assume that a relationship exists. Additionally, all teachers report positive spillover effects to other students and/or their own teaching skills in general, following the interventions implemented with specific cases in mind.

Biggs, J. (1996). Enhancing Teaching through Constructive Alignment. Higher Education, 32 (3), 347-364. Engeström, Y., & Sannino, A. (2010). Studies of expansive learning: Foundations, findings and future challenges. Educational Research Review, 5(1), 1-24. Engström, A. (2022). Nej, statens skolutvecklingsinsatser fungerar verkligen inte [No, the state's school development efforts really don't work]. Skola & Samhälle, 2022-12-12. Gee, J. P. (2008). A sociocultural perspective on opportunity to learn. In P. A. Moss, D. C. Pullin, J. P. Gee, E. H. Haertel & L. J. Young (Eds.), Assessment, Equity, and Opportunity to Learn. Cambridge University Press. Harlen, W. (2012). On the Relationship between Assessment for Formative and Summative Purposes. In J. Gardner (Ed.), Assessment and Learning, 2nd edition. Sage. Hsieh, H., & Shannon, S. E. (2005). Three approaches to qualitative content analysis. Qualitative Health Research 15(9), 1277–1288. Jahnke, A & Hirsh, Å. (2019). Varför förbättras inte elevresultaten trots alla insatser? En fördjupad nulägesanalys av en gymnasieskola [Why do student results not improve despite all efforts? An in-depth current situation analysis of a secondary school]. Ifous rapportserie 2020:1. Johannessen, K. (1999). Praxis och tyst kunnande [Practice and tacit knowledge]. Dialoger. Lindvall, J., Helenius, O., Eriksson, K. & Ryve, A. (2022). Impact and Design of a National-scale Professional Development Program for Mathematics Teachers. Scandinavian Journal of Educational Research, 66(5), 744–759. Sannino, A. (2022). Transformative agency as warping: how collectives accomplish change amidst uncertainty. Pedagogy, Culture & Society, 1–25. Skolverket. (2023). PISA. 15-åringars kunskaper i matematik, läsförståelse och naturvetenskap[PISA. 15-year-olds' skills in Mathematics, Reading comprehension and Science]. Rapport Internationella studier. Skolverket. Van den Hurk, H.T.G., Houtveen, A.A.M., & Van de Grift, W.J.C.M. (2016). Fostering effective teaching behavior through the use of data-feedback. Teaching and Teacher Education, 60, 444-451. Van Manen, M. (1995). On the Epistemology of Reflective Practice. Teachers and Teaching: theory and practice, 1(1), 33-50. Van Manen, M. (1991). The tact of teaching: The meaning of pedagogical thoughtfulness. The Althouse Press. Vygotsky, L. S. 1997 [1931]. The History of Development of Higher Mental Functions. In R. W. Rieber (Ed.) The Collected Works of L. S. Vygotsky, 207–219.