A cross-national study of learning environments in Taiwan and Australia is one example of research that employs both qualitative and quantitative methods. This paper describes the part of that study related to the development and validation of an instrument called the Teacher Student Interaction (TSI) which assess student perceptions of teacher behavior. After using the questionnaire with groups of students, the data were quantitatively analyzed, the questionnaire validated, and quantitative descriptions of teacher behavior obtained. To further validate the questionnaire and understand the teacher interactions according to the perceptions of students, a qualitative approach was used. Students were interviewed and the researchers visited and observed in science classrooms. (DDR)