Most generic curriculum reform efforts have to deal with a gap between the innovative aspirations of the initial designers and the daily reality of the intended audience of teachers. That tension is not alarming in itself. One might even say that without it no compelling reason for starting development work would exist. Unfortunately, many evaluation studies on the implementation and impact of curriculum development projects show that this discrepancy does not decrease over time. Apparently, not much improvement is made in detecting and reducing potential implementation problems. This article presents some conceptual and instrumental guidelines for dealing with these problems, focusing on the use of `profiles¿ during evaluation of curriculum materials. The paper starts with an introduction on the functions of exemplary curriculum materials and their possible representations, on the long road from original designers¿ ideas to effects of student learning. Next, we will explain the concepts of innovation and practice profiles. We will then provide guidelines for the development and use of such profiles, based on previous research experiences, and illustrated with some specific examples. Finally, we will reflect on the advantages and limitations of working with profiles.