Interest in studying teaching practices has increased, because of the need to evaluate teachers and dissatisfaction with the usual ways of doing it. Recent approaches with Value-Added Models, based on students' results on achievement tests do not seem satisfactory. The article is based on a review of literature and classifies the approaches to practices in three groups: instruments based on information given by teachers; observation protocols; and approaches based on the analysis of products of the practices. Specific tools are described and advantages and disadvantages of the three approaches are discussed.... [Leer más...]