For explanation:

Multiple sources exist for ideas for theory development and research in which many problem areas are identified within the domain of nursing to expand theory. In the recent times, nursing theory has originated from:

· Role Proliferation: Conceptualization of nursing as a set of functions became the focus of investigation, with theory evolving on how to prepare nurses for various roles.

· Basic Sciences: PhD education of nurses in sociology, psychology, anthropology, and physiology introduced ideas from other disciplines and stimulated new ways of looking at nursing phenomena.

· Nursing Process: Examination of processes in nurse-patient relationships and patient care triggered ideas and questions related to problem solving, priority setting, and decision making.

· Nursing Diagnosis: Labels were given to and a universal nomenclature was developed for problems that fall within the domain of nursing. These are actually conceptual statements about the health status of patients and, therefore, the first step in theory development.

· Concept Identification: Theory development encouraged identification of concepts central to nursing. Identification of relationships between concepts (propositions) defined a new nursing perspective.