The digitalisation of all areas of life and thus also of school education is a central topic throughout Europe, which is addressed in the "Digital Education Action Plan" (European Commission, 2020), among other things. This action plan represents an orientation at European level for the development of schools and school systems against the background of digitalisation, not only in times of the Corona pandemic. A first key goal of the action plan is to foster “the development of a high performing digital education ecosystem” (ibid., p. 10), in which inequalities are reduced at the same time. A second key goal is to enhance “digital skills and competences for the digital transformation” (ibid., p. 12), particularly to improve participation in democratic life.

In order to achieve these goals of the action plan, the professional competencies of teachers are relevant, which can be developed, for example, through collaboration among teachers (Drossel & Eickelmann, 2017). Teacher collaboration generally is an important feature of school quality at the school process level. It can be influenced by input-level factors such as teacher attitudes (e.g. Fraillon et al., 2019). However, due to the development towards becoming an information and knowledge society and the associated changes and challenges in the field of education, the collaboration between teachers is changing and so-called 'media-related collaboration' is becoming more relevant (Drossel, Heldt & Eickelmann, 2020; Drossel, Eickelmann & Schulz-Zander, 2017; Herro, Qian & Jacques, 2017; Hobbs & Corio, 2016). Thus, media-related teacher collaboration is highlighted as a key condition for the implementation of new technologies (Drossel, Eickelmann & Gerick, 2017).

Teacher collaborations in general can be associated with a variety of positive effects, such as professionalization or an increased willingness to innovate on the part of teachers (u. a. Thurlings & den Brok, 2017; Vangrieken, Dochy, Raes & Kyndt, 2015). Further studies suggest that media-related teacher collaboration can contribute significantly to maximizing instructional quality through the use of digital media (e.g. Cheung & Slavin, 2012). Additionally, the continuous developments of digital media, which constantly make adjustments to technical and educational requirements necessary while simultaneously offering new application possibilities, is said to be more manageable through teamwork (Drossel, Eickelmann & Gerick, 2017). Despite multiple indications of positive effects of (media-related) teacher collaborations, the international comparisons show, however, that teachers, especially in Germany, comparatively rarely practice media-related collaboration (Fraillon et al., 2019) and that the potentials thus often remain unused.

After reviewing the research, it becomes apparent that instructional teacher collaboration plays a significant role in the context of school quality and effectiveness, which are associated with multiple effects. It can be assumed here that teacher collaboration will itself change as a result of digitalisation-related developments, which is why there is also reason to believe that modified or new impact assumptions will result. The specific assumptions that may be associated with this have rarely been empirically recorded to date. This contribution therefore focuses the following research questions:

1. How do teachers assess the effectiveness of instructional teacher collaboration in the age of digitalisation (a) for their school, (b) for themselves as teachers, and (c) for their students?
2. To what extent do input and process level factors affect the assumptions of effectiveness?

The desiderata are processed in a German project named “Media-related Teacher Collaboration as Aspect of School Quality in the Digital World” funded by the Federal Ministry of Education and Research. The central concern of the project is to empirically map the media-related collaboration behaviour of teachers at lower secondary level in Germany. As part of this, the quantitative survey of a for Germany representative sample of N = 1214 lower secondary school teachers using computer-assisted personal interviews (CAPI) took place between November 2019 and January 2020. Three scales with a total of 17 items were designed to survey assumptions of effectiveness about teacher collaboration in the age of digitalisation – one regarding assumptions about the impact of teachers on the school (research question 1a), one regarding assumptions about the impact of teachers themselves (research question 1b), and one regarding assumptions about the impact on students (research question 1c). The impact assumptions are assessed on the basis of a four-point Likert scale ranging from 0 = strongly disagree to 3 = strongly agree. Descriptive analysis of those items are used to analyse the first research question. To answer the second research question structural equation modelling (Bowen & Guo, 2012) is used with the inclusion of further factors of input- and processlevel.

With regard to RQ1 is to report that at the school level (RQ1a), particular reference is made to facilitated coordination processes and simplified access to information that result in media-related teacher collaboration. At the level of the teachers (RQ1b), the results provide indications that teacher collaboration can contribute the professionalization of teachers even in the age of digitalisation. In addition, the results show that teachers can save time and effort and that it is easier to prepare lessons. At the level of the students (RQ1c), effects are also highlighted with regard to the individual support of the students, but also with regard to a more systematic support of media-related competencies. Overall, it appears that teachers everywhere attribute positive impact assumptions to collaborations, but they tend to be reluctant to do so. With regard to RQ2, it becomes apparent that collaboration-related impact assumptions are particularly related to collaboration frequency as well as cooperation culture and school management behaviour. The culture of collaboration and the actions of the school management are also related to the attitudes towards collaboration at the input level and are also related to the frequency of collaboration. The teachers' generally positive but rather cautious assessments of effectiveness can possibly be attributed to the fact that media-related teacher collaboration has often not yet been practiced extensively. Accordingly, there is reason to believe that more positive assessments of the effects may only emerge in the medium and long term, when the practice of collaboration has intensified in schools. This needs to be tested empirically in further research, thus under consideration of different educational systems in different countries. Overall, ICT-related teacher collaborations are a valuable professionalization measure to address challenges in implementing digital media in all European countries, as they are anchored in the “Digital Education action plan” (European Commission, 2020).

Bowen, N.K.; Guo, S. (2012): Structural equation modeling. New York, Oxford: Oxford University Press. Cheung, A. & Slavin, R.E. (2012). The Effectiveness of Educational Technology Applications for Enhancing Reading Achievement in K-12 Classrooms: A Meta-Analysis. Baltimore, MD: Johns Hopkins University, Center for Research and Reform in Education. Drossel, K., & Eickelmann, B. (2017). Teachers’ participation in professional development concerning the implementation of new technologies in class: a latent class analysis of teachers and the relationship with the use of computers, ICT self‑efficacy and emphasis on teaching ICT skills. Large-Scale Assessments in Education, 5(19), 1–13. Drossel, K., Eickelmann, B. & Gerick, J. (2017). Predictors of Teachers’ Use of ICT in School – the Relevance of School Characteristics, Teachers’ Attitudes and Teacher Collaboration. Education and Information Technologies, 22(2), 551–573. Drossel, K., Eickelmann, B. & Schulz-Zander, R. (2017). Determinants of teachers´ collaborative use of ICT for teaching and learning. European Educational Research Journal, 16 (6), 781-799. Drossel, K., Heldt, M. & Eickelmann, B. (2020). Lehrer*innenbildung durch medienbezogene Kooperation. In K. Kaspar, M. Becker-Mrotzek, S. Hofhues, J. König & D. Schmeinck (Hrsg.), Bildung, Schule und Digitalisierung (S. 45-50). Münster: Waxmann. European Commission (2020). Digital Education Action Plan 2021-2027. Resetting education and training for the digital age. Retrieved from: https://ec.europa.eu/education/sites/default/files/document-library-docs/deap-communication-sept2020_en.pdf Fraillon, J., Ainley, J., Schulz, W., Friedman, T., Duckworth, D. (2019). Preparing for Life in a Digital World. IEA International Computer and Information Literacy Study 2018. International Report. Amsterdam: IEA. Herro, D., Qian, M. & Jacques, L. (2017). Increasing Digital Media and Learning in Classrooms through School-University Partnerships. Journal of Digital Learning in Teacher Education, 33 (1), 32-42. Hobbs, R. & Coiro, J. (2016). Everyone Learns from Everyone. Collaborative and Interdisciplinary Professional Development in Digital Literacy. Journal of Adolescent & Adult Literacy, 59 (6), 623-629. Thurlings, M. & den Brok, P. (2017). Learning outcomes of teacher professional development activities: a meta-study. Educational Review, 69 (5), 554-576. Vangrieken, K., Dochy, F., Raes, E. & Kyndt, E. (2015). Teacher collaboration: A systematic review. Educational Research Review (15), 17-40.