Theoretical and Scientific Foundations for Nursing Practice

Nursing is a profession that requires both practical skills and theoretical knowledge. Nursing practice is based on scientific principles and evidence, as well as ethical and moral values. However, nursing is also influenced by various theories and models that help nurses understand, explain, and predict human behavior, health, and illness. In this blog post, we will explore some of the major theoretical and scientific foundations for nursing practice, and how they can guide nurses in their clinical decision-making and interventions.

Nursing Theories

Nursing theories are conceptual frameworks that describe, analyze, and predict phenomena related to nursing. They provide a basis for developing nursing knowledge, practice, education, and research. Nursing theories can be classified into four levels: metatheory, grand theory, middle-range theory, and practice theory.

Metatheory is the most abstract level of nursing theory. It examines the nature, scope, and purpose of nursing as a discipline and a profession. It also addresses the philosophical and methodological issues of nursing knowledge development. An example of a metatheory is the Theory of Nursing Knowledge/Wisdom by Carper (1978), which identifies four ways of knowing in nursing: empirical, ethical, personal, and aesthetic.

Grand theory is a broad level of nursing theory that provides a comprehensive perspective of nursing phenomena. It covers the concepts of person, environment, health, and nursing. Grand theories aim to explain the nature and goals of nursing practice, as well as the relationships among the concepts. An example of a grand theory is the Self-Care Deficit Theory by Orem (1991), which states that nursing is required when people are unable to meet their self-care needs due to illness or disability.

Middle-range theory is a more specific level of nursing theory that focuses on a particular aspect of nursing phenomena. It has a narrower scope and more empirical support than grand theories. Middle-range theories aim to describe, explain, or predict outcomes related to nursing interventions or situations. An example of a middle-range theory is the Theory of Comfort by Kolcaba (2003), which defines comfort as a state of physical, psychological, social, and environmental well-being that results from satisfying human needs.

Practice theory is the most concrete level of nursing theory that guides the actions of nurses in specific clinical settings. It has a limited scope and applicability than middle-range theories. Practice theories aim to prescribe or recommend specific actions or behaviors for nurses to achieve desired outcomes. An example of a practice theory is the Theory of Planned Behavior by Ajzen (1991), which states that human behavior is influenced by attitudes, subjective norms, and perceived behavioral control.

Scientific Principles and Evidence

Nursing practice is also based on scientific principles and evidence that are derived from natural and social sciences. Scientific principles are general laws or rules that explain how natural or social phenomena occur or behave. Evidence is the information or data that support or refute a claim or hypothesis. Scientific principles and evidence help nurses to understand the causes and effects of health problems, as well as the effectiveness and safety of interventions.

Some examples of scientific principles that are relevant to nursing practice are:

– The principle of homeostasis, which states that living organisms tend to maintain a stable internal environment despite external changes.
– The principle of infection control, which states that microorganisms can cause diseases and can be transmitted through direct or indirect contact.
– The principle of pharmacokinetics, which states that drugs are absorbed, distributed, metabolized, and excreted by the body in different ways.
– The principle of ethics, which states that human actions should be guided by moral values and principles.

Some examples of sources of evidence that are used in nursing practice are:

– Systematic reviews, which are summaries of the best available evidence on a specific topic or question.
– Randomized controlled trials, which are experiments that compare the effects of an intervention with a control group.
– Clinical guidelines, which are recommendations for practice based on current evidence and expert consensus.
– Case studies, which are descriptions of individual cases or situations that illustrate a problem or solution.

How Theories and Evidence Guide Nursing Practice

Theories and evidence guide nursing practice by providing a framework for thinking critically and creatively about health issues and interventions. They help nurses to:

– Identify relevant concepts and variables that affect health outcomes.
– Formulate hypotheses or questions that can be tested or answered by evidence.
– Select appropriate methods and tools for collecting and analyzing data.
– Interpret and evaluate the results and implications of data.
– Apply the findings to plan, implement, and evaluate interventions.
– Communicate the rationale and evidence for interventions to patients, families, colleagues, and other stakeholders.


Nursing practice is based on both theoretical and scientific foundations that inform and support clinical decision-making and interventions. Nursing theories provide a conceptual basis for understanding, explaining, and predicting nursing phenomena. Scientific principles and evidence provide an empirical basis for assessing the causes and effects of health problems and interventions. By integrating theories and evidence, nurses can enhance their knowledge, skills, and competencies in providing quality and safe care to patients.


Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50(2), 179-211.

Carper, B. A. (1978). Fundamental patterns of knowing in nursing. Advances in Nursing Science, 1(1), 13-23.

Kolcaba, K. (2003). Comfort theory and practice: A vision for holistic health care and research. Springer Publishing Company.

Orem, D. E. (1991). Nursing: Concepts of practice (4th ed.). Mosby.

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