31 David Nettleton Hernandez, L 1999 Congress of the European Society of Fuzzy Logic and Technology - EUSFLAT '99 Palma de Mallorca 283-286 sleep apnea diagnosis, questionnaire responses, WOWA aggregation, clustering, classification, reliability, relevance. In this article, joint medical and data analysis expertise is brought to bear using contrasting data analysis methods and the WOWA aggregation operator to solve a difficult medical diagnosis problem, that of sleep apnea syndrome screening. We describe a method of calculating the relevance and reliability weights used by the WOWA operator.