OBJECTIVES: To utilize responder rate to demonstrate the improvement of negative symptoms and quality of life (QoL) associated with olanzapine (OLZ) versus risperidone (RIS). METHODS: Data were analyzed post-hoc from a large, prospective, randomized, 28-week, double-blind trial, conducted with 339 patients who met the DSM-IV criteria for schizophrenia, schizophreniform disorder, or schizoaffective disorder. Three methods of outcome measurement (mean score change, proportion of responders and time to response) were used to compare improvement in the Scale for Assessment of Negative Symptoms (SANS) and the Quality of Life Scale (QLS) scores across groups. RESULTS: At the end of the 28-week treatment, significantly more OLZ- than RIS-treated patients reached the thresholds of 30%, 40% and 50% improvement in SANS and of 20%, 30% and 40% improvement in QLS. OLZ-patients also demonstrated a more rapid improvement in SANS and QLS than RIS-patients. CONCLUSIONS: The greater effectiveness of OLZ versus RIS was demonstrated by the greater proportion of patients who had access to a higher level of clinically relevant response of negative symptoms and improvement of QoL. Treatment effectiveness may be a better indicator of the chance of achieving superior functional goals.