This paper reports the development of an instrument for monitoring teaching strategies in the teaching of mathematics. The main purpose of research into this area was to determine the aspects of mathematics teaching which result in differential learning within a class. A second purpose was the development of a theoretical model for the teaching process. This model is based on the assumption that the teaching process is a system of transformations which operate according to a set of rules which are derived from organizational and time considerations. Developed in Sweden, the instrument was designed to be used in deciding on teaching strategies to be used with the new Swedish national mathematics curricula. (SD)