Mixed tribunals are decision-making bodies in which professional and lay judges jointly decide criminal cases. Detailed questionnaires were distributed to 56 professional judges, 175 lay judges, 40 state attorneys, and 102 attorneys in two regions of Croatia in 1993. Respondents were asked for their views about mixed tribunals and about lay judges' contributions. The study used status characteristics theory to explain the interaction in the mixed tribunals. According to this theory, individuals who interact in task-oriented groups acquire expectations about the potential task-related contributions of the members of their group. Lay judges from big cities were perceived to disagree with the professional judges more than the lay judges from small towns. The ideal arrangement to encourage both active participation and a statement of disagreement is to reduce the differences in educational levels and in the levels of occupational prestige and to remind professional judges about the importance of the contribution of lay participants. Notes, tables, references