Services have various unique characteristics compared to other types of products. Any approach to quality control of services must respect and be based on these unique characteristics. In addition to the often mentioned four major characteristics of services -- intangibility, variability, inseparability and perishability, some authors also mention other unique characteristics -- "customer as input and co-producer of service" among them. According to available sources, the relation between four major characteristics of services and problems of quality was proved, but research concerned with the "customer as input and co-producer of service" characteristic is rare. However, in the case of university education, the characteristic "customer as input and co-producer of service" is of key importance. This article uses statistical analysis of survey results in order to prove the validity and importance of this unique characteristic for the field of university education. Research results are based on the evaluation of an enquiry action (questionnaire) in which a total of 243 responses from the graduates of the Faculty of Management Science and Informatics of the University of Žilina in Žilina were processed.