Theories play an essential role in organizing patient care. Theories refer to a proposed or followed belief, policy, or procedure that is the basis for action. Nursing theories are knowledge-based concepts that guide nurses' actions, influence nursing education and practice, and allow nurses to care for their patients.

Theories provide a perspective to assess patients' conditions and organize data and methods. They also assist in analyzing and interpreting information. They represent a phenomenon using fundamental concepts, definitions, and assumptions. A phenomenon is a label or term that describes an idea or response to an event. For example, patient responses to stress are a phenomenon.

Concepts refer to ideas or mental images that help describe the phenomenon, for example, how the sociocultural or physiological factors related to stressors affect the patient. Definitions reflect the concept's general meaning and the activities necessary to measure it within a theory, such as defining what stress means and patient responses. Finally, assumptions are statements that explain the relationships among the concepts.

The metaparadigm is a set of four interrelated fundamental concepts in nursing theory. Although these concepts appear in all nursing theories, their definitions and relationships may vary. The metaparadigms are essential for nursing theories and include the person, environment, health, and nursing component.

The metaparadigm for nursing theory includes:

• A person refers to the recipient of nursing care and may comprise individual patients, families, groups, and communities.
• Health has unique meanings for the individual patient, the healthcare setting, and the provider. The nurse should provide optimal care based on the patient's healthcare needs.
• The environment includes patients' surroundings that can influence their health and wellness—for example, physical, social, and occupational environmental factors.
• The nursing component is representative of nursing skills and the knowledge to carry out the duties and responsibilities associated with patient care.

For example, the metaparadigms in Orem's Self-Care Deficit Theory are:

• The person represents men, women, and children cared for individually or as social units. A person should be able to perform the activities necessary to preserve the quality of life at a high level.
• Health is an individual's structurally and functionally sound state. Also, it is a state that encompasses individuals' and groups' health.
• The environment plays an essential role in promoting an individual's health. It includes family, culture, and community.
• Nursing provides specialized assistance to disabled individuals to meet necessary self-care needs. The nurse also participates in the medical care the person receives from the provider.