In a prospective study we compared the ability of two quality assessment methods--the standard criteria list and the criteria map--to predict the appropriateness of the disposition decision for 421 patients with chest pain who presented to two emergency departments. To evaluate the quality of this decision, each patient was followed at home or in the hospital to determine whether an acute condition requiring hospital admission was present. Among the 169 discharged patients, the map scores of the eight with admissible disease were significantly higher than the score for those without admissible disease (p = 0.02). For the 252 admitted patients, a similar relationship between map score and the admissible disease outcome was observed (p = 0.0001). There was no significant relationship between list score and outcome among either the admitted or the discharged patients. Multivariate logistic analyses confirmed the importance of the map score as a predictor of admissible disease. The map score was superior to the list score and to demographic variables in its ability to correctly classify patients with and without admissible disease. The demonstrated relationship between map score and patient outcome enables the map to be used in a quality assurance system. An institution can ensure that physicians review an enriched sample of the inappropriate discharges and the unjustified admissions by selecting admitted patients with low map scores and discharged patients with high map scores.