Determining the effectiveness of schizophrenia treatments requires aggregate measures that reflect the relative importance of schizophrenia's multiple outcome domains. A lack of understanding of the relative importance of various domains prevents meaningful aggregation of outcome measures and limits inferences drawn from treatment research. This study is designed to develop and apply methods for determining the importance of schizophrenia treatment outcomes by adapting preference assessment methods used in general health status research. The first of two study phases is devoted to method development. Four preference assessment methods (category rating, time trade-off, paired comparison and direct importance rating) used successfully in prior health status research will be evaluated in two expert groups, one comprised of clinicians providing schizophrenia treatment and one of persons with schizophrenia. In the second phase, the two preference assessment methods found to be most feasible, valid and reliable in the method development phase will be compared in a randomized, factorial design including 4 stakeholder groups directly and indirectly involved in schizophrenia treatment (persons with schizophrenia, clinicians providing schizophrenia treatment, family members of persons with schizophrenia and members of the general public). This method and group comparison will (1) determine which methods perform comparably across stakeholder groups in terms of feasibility, validity, reliability and efficiency, (2) determine whether stakeholder group membership or other demographic characteristics affect preferences for treatment outcomes, (3) identify methods best suited for use in future studies of schizophrenia treatment outcome, (4) generate preference weights for key outcomes which can be applied retrospectively to existing research findings as well as in future studies where preference assessment is not practical. Study findings will also inform the study of other serious mental disorders and help to resolve prevailing controversies about the importance of method and stakeholder group differences in health status preference assessment.