Current trends and missing links in studies on teacher professional development in science education: a review of Design Features and Quality of Research (2012) Jan H. van Driel, J. A. Meirink , K. van Veen & R. C. Zwart Focus: content and pedagogical content knowledge Active: inquiry-based and practice-based Collaborative: build PLCs and co-design PD with Ts Sustained: structured and sustained Coherence: theory of improvement Contextualized: adapt to content, context, process