This article reviews recent work on the assessment practices of educational psychologists. The evidence suggests that current legislation has driven many practitioners back to the paradigms of the 1960s and 1970s, and that these paradigms prevent them from making substantial contributions to the effectiveness of special education. The discussion considers the relevance of socio-cognitive conceptualizations of motivation in understanding the reasons for educational psychologists’ lack of impact on school effectiveness in general, and on the effectiveness of special education in particular. The current bureaucracy of professional practice in Britain prevents educational psychologists from paying more than lip service to cultural diversity, active parental involvement, and children’s own perspectives on the education they are ‘delivered’. If educational psychologists are to rediscover the principles of professional service to child clients, three things are necessary: first, a clearer and more explicit distinction between their responsibilities to children and their responsibilities to their employing education authority; second, an inclusive approach to the concept of special education which ceases to see it as separate from mainstream education; third, a paradigm of professional practice which incorporates the social psychology of schooling into more traditional individualistic approaches.