Technology-enriched schools offer unique opportunities for research into the use of information technology in education. As in every applied educational research project, some concerns should be carefully considered. One of them is teacher involvement. Another issue of concern is finding a proper balance between development and controlled research. In the Dutch Technology-Enriched School project three schools were equipped with exceptional hardware and teacher facilities. An implementation strategy of progressive broadening was applied. At the start of the project, a small number of interested teachers was invited to join the project. These avant-garde teachers based their enthusiasm primarily on the leading principle of the project: using information technology to improve the quality of education. Teachers and researchers closely collaborated to develop, implement and evaluate teaching units with the computer as an aid to teaching and learning. After some years of experience, in which examples of good practice were created, the project's scope was broadened to enable new teachers to join the project. Some of these teachers were perhaps less personally convinced of the value of the project's leading principle than the avant-garde teachers, but they were better able to evaluate costs and benefits. Finally, the implementation strategy of progressive broadening resulted in a change in attitudes of the teachers: they began to see themselves as active contributors and participators in the process of educational change.