Traditionally, the teacher's role in educational research has been passive, his contribution consisting largely of completing questionnaires, responding to interview schedules, assisting in the administration of testing programmes and, more recently, being observed in his classroom. Researchers talk of using schools for their projects and, commonly, teachers observed in his classroom, teachers have played little part in either identifying areas of enquiry or in selecting methods appropriate to their exploration. There are signs however of a move towards teachers' more active involvement. Curriculum projects from the mid-60's have provided examples of how teachers can play a key role in the development of innovation in the classroom. The proliferation of new materials, techniques and forms of organisation have sharpened teachers' perceptions of the need for evaluation do the new ways work any better? and the possible contribution of research to classroom practice has become more apparent. Researchers, in their turn, are increasingly concerned about the impact and take-up of their product, kinds of question being posed and different aspects of the teaching and learning situation being explored. In particular, the classroom has emerged as a focus of study and perceptions of what happens there by teacher, pupil and observer form the crux of a growing number of studies. These trends were reflected when the NFER decided to sponsor a major research into mixed ability teaching in secondary schools. The project's brief was explicit that the approach adopted should be with the research team working with groups of teachers in various parts of the country with a view first to defining areas of particular concern, and second, to generating, implementing and evaluating strategies designed to meet them. The project started in October 1975 and in its first nine months some thirty teacher groups have met in those areas of the country where the project is focussing its activity. These were selected to provide a variety, both in terms of geographical and social factors and in the nature and duration of mixed ability grouping being employed. There has therefore been the opportunity to study the functioning of teacher groups in a variety of settings, and whilst the project is still in its early stages, it is possible to make some interim statement of the kind of contribution which teacher groups can make, and to identify factors which may be related to the success or failure of the collaborative mode of operation in a national research project. Certainly of major importance appears to be the expectations of those teachers taking part; in what ways do they perceive research as helping them; what kind of role do they anticipate carrying out in such collaborative exercises; what are their perceptions of how research operates and what is their knowledge of possible methods of investigation; what spin-offs other than those which might occur in their classrooms do they anticipate from such a large investment of their personal time? Taking the first of these, there is little doubt from our experience that teachers voluntarily take part in the project because it will provide practical help with the problems they face each day in the classroom. The way in which such problems are perceived predictably varies according to experiences; hence in those areas where mixed ability teaching is a recent innovation, teachers tend to be concerned with the very immediate problems of finding resources and techniques for teaching a particular subject to a particular year group. Where unstreaming has operated for a substantial period, the questioning becomes more abstract. Such schools have generally amassed sufficient resources to be 27 able to cope; the problems which confront them are at a different and more fundamental level, and tend to cut across the barriers of subject disciplines.