The growing interest in alternative dispute resolution generally and environmental mediation in particular has provoked both enthusiasm and
skepticism. Mediation enthusiasts see not only a more effective way to address complex disputes, but also the possibilities of more deliberative politics. Critics argue that some of the claims made for mediation are overblown or unsubstantiated. Evaluation research has become one of the principal vehicles for testing the claims about environmental mediation and other collaborative problem-solving processes, for enlarging our understanding of practice-related issues, and for ensuring accountability. In this chapter, we outline some of the promises and criticisms of environmental mediation. We then explore several questions about the dominant evaluative purposes and research strategies reflected in current evaluative studies.