Combining theories

Pessia Tsamir and Dina Tirosh have written an article about Combining theories in research in mathematics teacher education. This article was published in ZDM two days ago. In this interesting article, they examine how the combination of the theories of Shulman and Fischbein "may contribute to the evaluation of mathematics teachers' (prospective and inservice) knowledge". Here is the article abstract:
In this paper, we describe how the combination of two theories, each embedded in a different realm, may contribute to evaluating teachers’ knowledge. One is Shulman’s theory, embedded in general, teacher education, and the other is Fischbein’s theory, addressing learners’ mathematical conceptions and misconceptions. We first briefly describe each of the two theories and our suggestions for combining them, formulating the Shulman–Fischbein framework. Then, we present two research segments that illustrate the potential of the implementation of the Shulman–Fischbein framework to the study of mathematics teachers’ ways of thinking. We conclude with general comments on possible contributions of combining theories that were developed in mathematics education and in other domains to mathematics teacher education.