Teachers of science, mathematics and technology Australia wide are being required to transform their established epistemologies of practice in order to engage learners as active conceptualisers within socially interactive learning environments. Many teachers are enrolling in postgraduate distance education programs to assist them with this challenging task. Curtin University is responding by using computer mediated communication to speed up the exchange of distance study materials and to provide online interactive learning environments (via chat groups, bulletin boards and email). For the past three years, the authors have been using the Internet to teach online Masters degree students studying at a distance from Curtin. The major pedagogical goal is to engage students (professional teachers) in reflective and collaborative learning. The web sites provide Activity Rooms in which the teachers engage students in frequent and focused discourse with each other and with their online tutors. As reflective teachers, the authors are keen to evaluate their own innovative practices and constantly improve them. To this end, they have designed the Constructivist On-Line Learning Environment Survey (COLLES), an electronic questionnaire that enables them to readily monitor each student's preferred online learning environment and compare it with her/his actual experiences. In this presentation, they outline the rationale of the questionnaire and present some preliminary analyses that illustrate its usefulness. [Author abstract, ed] Teachers of science, mathematics and technology Australia wide are being required to transform their established epistemologies of practice in order to engage learners as active conceptualisers within socially interactive learning environments. Many teachers are enrolling in postgraduate distance education programs to assist them with this challenging task. Curtin University is responding by using computer mediated communication to speed up the exchange of distance study materials and to provide online interactive learning environments (via chat groups, bulletin boards and email). For the past three years, the Internet has been used to teach online Masters degree students studying at a distance from Curtin. The major pedagogical goal is to engage the students (professional teachers) in reflective and collaborative learning. Curtin's web sites provide Activity Rooms in which students are engaged in frequent and focused discourse with each other and with their online tutors. To evaluate and improve on their teaching practice, the academic staff designed the Constructivist On-Line Learning Environment Survey (COLLES), an electronic questionnaire that enables them to readily monitor each student's preferred online learning environment and compare it with her/his actual experiences. This paper outlines the rationale of the questionnaire and presents some preliminary analyses that illustrate its usefulness