The method of organizing nursing care known as ‘primary nursing’ is increasingly being introduced into hospital wards on the assumption that it will have beneficial effects for both patients and staff Operational definitions of primary nursing, essential to provide replicable research into the organization of nursing care, are, however, lacking in available research literature This study describes the development of a questionnaire intended to identify and discriminate between three methods of organizing nursing staff and nursing work task allocation or functional nursing, team nursing and primary nursing The questionnaire was distributed to 36 ward sisters on 27 acute and rehabilitation care of the elderly wards. Questionnaires were returned from 17 wards, a response rate of 63% Findings indicate that few wards meet five or more criteria for classification as a particular method of nursing organization The findings illustrate the difficulties in matching and discriminating between wards in order to conduct research in which organizational modality is an independent variable