This self-administered client questionnaire and global rating scale is based on a conceptual model that includes six dimensions: commitment, social-psychological factors, values, understanding, skills, and conflict. Instrument development and refinement included observations of divorce mediation, interviews with mediators, and clients, and focus groups. Reliability evaluations show that the interitem correlations of the scales is low, indicating that items are rather discrete. Alpha reliabilities increased between the pilot and the refined instrument in all but two subscales, and internal consistency of the scales is very high. Validity evaluations showed a reasonable correlation between clients' self-ratings and scale scores except for the values and skills dimensions. Correlations between mediators' clinical ratings and subscale scores were higher than those for clients except in the area of conflict. Clinical validity of the instrument is high, and future evaluations will examine discriminant validity based on the instrument's ability to distinguish successfully and unsuccessfully mediated cases. When further refined, the instrument should be useful in screening couples and identifying specific problems and issues that should be addressed by the mediation process. 2 tables and 41 references.