A method for establishing a performance characteristic of a hearing device (8, . . . , 11) is described. The method comprising the steps of collecting data in relation to the hearing device (8, . . . , 11) and/or its user, identifying characteristics of the hearing device (8, . . . , 11) and/or its user via at least a part of the collected data, providing a data base (2) comprising data of other hearing devices and/or its users, determining a set of data from the data base (2) on the basis of the identified characteristics, establishing a relation of at least a part of the collected data to the set of data from the data base (2), and establishing the performance characteristic from said relation.