The aim of this paper is to present a tool we built, that can bring out the effects of Lesson Studies (LS) on teacher’s professional development. This tool, meant to suit all LS contexts around the world, indicates what type of data to collect and how to use it, so we can produce comparable results, in order to assert the effectiveness of LS.
To do this, we try to collect data that is naturally produced in a LS process, so we don’t add work to participants. To select such data, we firstly present our common definition of LS. Based on a literature review, this redefinition of the process takes into account three types of LS and several adaptations they went through in various contexts. This model shows common features that we can consider as essential in LS, but also lists several Add-ons, each of which can be a key to break a stalemate, to overcome a hindrance or simply to help organising the research of a LS group according to its goals.
This common LS’s skeleton allows us to determine which data will be naturally produced during the process. Among it, the data our tool suggests to collect has to bring out the effect of each LS feature on teachers’ development. So, we secondly briefly determine what we mean by “teachers’ development” and how to measure it, especially regarding the goals of the LS team.
Lastly, we present how we are going to test this tool in the scholastic context of Lausanne, French-speaking Switzerland, at the University of Teacher Education. This environment brings some adaptations to the LS process, due to the specificities of pre-service teachers training. This is an opportunity to check the adaptability of our tool. After this test phase, we will refine our tool and put it into practice in different situations.