The aim of this contribution is to draw up a theoretical framework to evaluate Lesson Studies (LS)
embedded in the schooling context in Lausanne, in the French-speaking part of Switzerland. Firstly,
we provide a (re)definition of LSs through a comprehensive literature review. Some reference works
like the books of Lewis & Hurd (2011) or Fernandez & Yoshida (2004) enable their readers to build a
clear comprehension of what LSs are and how they should be implemented. But the LS practices
reported in scientific journals show some variation compared with the theoretical model. To evaluate
such a process, we postulate that one has to clearly define what is supposed to be measured and
identify its limits. Secondly, we present a synthesis of the different ways to measure the effects of LS as
reported in the literature. This second focus leads us to list and discuss the features and components
of LS which could (or should) be evaluated and the data to be collected to do so. At the same time, our
work highlights some differences between LS practices depending on the variation of several
parameters. These two topics lead us to question the effects expected from each feature and
component of an LS. Some elements are not on the existing list of essential features of an LS. Others,
experimented in groups of teachers, are not even mentioned in the reference literature. Yet they can be
keys to breaking a stalemate, to overcoming a barrier or simply helping organise the research of a LS
group according to their goals. In March 2017, we submitted this presentation and a database of such
keys and their expected results for discussion in the Scientific symposium organised by the Postgraduate
Studies Program of the Department of Education Sciences in Early Childhood “Innovative
educational approaches in multi-cultural educational environments” (Democritus University of
Thrace) and the Municipality of Alexandroupolis (GR). This article reports the main ideas of this
presentation.