The validation of a structured group judgment procedure to establish priorities for quality assurance activities was undertaken in six medical institutions in the United States. Validation focused on the extent to which health improvement could be documented by outcome-based projects focusing on priority topics. Predictive (criterion-related) validity was sought by analyzing five successively more stringent levels of evidence: 1) feasibility of implementing a quality assessment project within the topic areas selected by the prioity procedure; 2) accuracy of identifying health deficiencies or strengths; 3) verification of establishing correctable causes of health deficiencies; 4) capability of effecting significant improvement of health deficiencies; and 5) credibility of evidence that improvement achieved is directly attributable to corrective actions taken. Within the limits of generalizability, predictive validity was documented at every level of analysis. It is recommended that the structured group judgment process used in this study be more thoroughly evaluated and considered for quality assurance planning purposes.