Abstract
This qualitative research shows that, when judging the quality of medical services, their high credence attributes and high significance to the client tend to diminish the action spectrum of the implicit promises, causing supporting elements to be necessary for this judging. A consequent suggested addition to the theory of services Marketing is that the weight of credence attributes would enhance the criticality of the providers’ role as impersonators of the services in the eyes of customers, and would also limit the action spectrum of implicit promises upon the perception of quality of these services.