As theories in the field of education continue to multiply and divide, it becomes increasingly urgent to determine how we can make use of this diversity to inform educational practice. In this symposium, four research projects are reported in relation to three different educational areas: science, literacy and mathematics education. Each of the four research projects has purposefully employed multiple theoretical lenses within the one research project. Each presentation addresses a different aspect of the question: What are the challenges and benefits of multiple theories within a single study to promote our understanding of learning and teaching?

The presentation of the four research studies is sequenced for this presentation according to the extent to which the research design anticipated the purposeful integration of the results of the constituent analyses. In the Learner’s Perspective Study (LPS), video and other data was generated in mathematics classrooms in a dozen countries. The project’s overarching research question was the characterization of patterns of participation from the perspective of the learner. Since the inception of the project in 1999, many additional parallel analyses have been undertaken by different members of the international research team, using a wide variety of theories to inform the analyses. The question posed in this paper concerns the methods and legitimacy of the process of synthesizing these diverse analyses into a coherent portrayal of the mathematics classroom. Chan’s work on early literacy involved applying item response theory, thematic analysis, and individual case analysis of the responses of 293 four to six-year-old children to some early literacy assessment tasks. One question posed in this paper is whether the most useful purpose of research is to generalize universal laws (nomothetic) or to explain the unique case (idiographic). Adopting the position that these goals are complementary to each other, the paper focuses on reconciling the different portrayals of early literacy offered by these different analyses. In the third study of university students solving physics problems, different theories were purposefully applied in a series of stratified analyses. Level one employing phenomenography and variation theory, level two using positioning theory and level three making use of the techniques of conversation analysis. This multi-layered approach was not pre-determined in the research design but emerged as each level of analysis revealed potential for further interrogation of the data. In the final study of 8^th grade science classrooms, analyses employing different theories were anticipated in the research design from the outset. Positioning theory, systemic functional linguistics, distributed cognition and variation theory were deliberately selected because of differences in the aspect of classroom practice foregrounded by each theory. The project design anticipated the production of complementary accounts produced by the parallel analyses and a major goal of the project was the reflexive interrogation of both the science classroom as a learning environment and of the various theories with respect to their capacity to provide insight into that setting. In combination, these four projects raise many questions about the challenges and benefits offered by research studies employing multiple theories.