Issue/question: To foster teacher learning and school improvement, the Dutch Ministry of Education has supported 22 professional learning networks (PLNs) over four years. Groups of, on average, 15 teachers from different schools are guided by teacher educators to work collaboratively on designing new curriculum material, develop their research capacities, or both. Longitudinal research into these PLNs focuses on effects on teacher professional development and influencing factors. To gain more insight into processes, influencing factors, and teacher learning, five PLNs were selected as case studies. A myriad of factors need to be in place before networks can be successful (Katz & Earl, 2010; Stoll et. al, 2006). At the same time, the balance between (external) guidance and participant ownership needs to be maintained. Moreover, PLNs struggle with challenges of knowledge dissemination and sustainable school improvement. In this paper we compare and contrast the cases to provide insight into processes, factors, effects, and knowledge dissemination and sustainability. Key ideas/approach: The theoretical framework is based on Desimone et al., (2013), distinguishing two central components: a set of critical features for effective professional development, such as ‘reflective dialogue’ and ‘structured and guided activities’, included as influencing factors in this study. The second critical feature is an operational theory of how professional development works to influence teacher and student outcomes: 1) teachers experience professional development with effective features, 2) this increases teachers’ knowledge, skills and/or attitudes, 3) these knowledge, skills and attitudes are used to improve instruction. This is expected to lead to 4) improved student learning. We used a qualitative case study approach with teacher interviews, PLN meeting observations, teacher educator interviews and their logs from three years as data. Main findings: The teacher educators have intensified coaching throughout the years, and teachers report to have learnt and applied as a result of PLN collaboration. Examples are developing a critical attitude, and developing new lesson series or instruments for research in schools. Knowledge dissemination and approaches to sustainability are handled and experienced differently. In one PLN, for example, school leaders are increasingly involved and there is a plan to facilitate knowledge dissemination in participating schools. In the paper an extensive comparison and good practices are presented, and an extended framework for knowledge dissemination and sustainability is discussed.

Desimone, L., Smith, T., & Phillips, K. (2013). Linking student achievement growth to professional development participation and changes in instruction: A longitudinal study of elementary students and teachers in Title I schools. Teachers College Record, 115(5), 1-46. Katz, S., & Earl, L. (2010). Learning about networked learning communities. School Effectiveness and School Improvement, 21(1), 27-51. doi: 10.1080/09243450903569718 Stoll, L., Bolam, R., McMahon, A., Wallace, M., & Thomas, S. (2006). Professional learning communities: A review of the literature. Journal of Educational Change, 7(4), 221-258. doi: 10.1007/s10833-006-0001-8