Numbers of important nurse theorists such as Clara Weeks-Shaw, Isabel Hampton Robb, Imogene King, Hester Frederick, Myra Levine, Hildegard Peplau, Bertha Harmer, and Virginia Henderson contributed to the emerging discipline by describing various nursing models throughout the late 19th - late 20th centuries (Wesley, 1995).
Each model of nursing has two elements: a method to assess individual needs of the patient and a method to implement the adequate type of care. These elements are used to a document known as a 'care plan' that is employed to identify the essential characteristics of a patient's treatment by doctors, nurses or/and health professionals. The process of treatment is measured and the quality of a patient's care is evaluated with appropriate changes being done to the care plan (Polit, & Hungler, 1995).
In the 19th century, nurses were predominantly viewed as mere executors of the doctor's prescribed care. Such limited perception of the nurse's function resulted in emergence of a set of biomedical models of nursing that continue to strongly affect the modern nursing practices (Snyder, 2001). The key characteristic of the biomedical model is excessive attention to pathophysiology and altered homeostasis which did not allow advocates of this approach to properly identify individual differences between the patients. Consequently, although the biomedical model was effective for traditional medical and physical care, it failed repeatedly in cases which went beyond traditional frameworks: the focus on the treatment of disease prevented the nurses and doctors from making appropriate account of sociocultural, psychological, religious, or economic differences between the patients (Hawkins, 1987).
The development of constructivist, functionalist, and interpretive epistemologies over the second half of the last century led many to revise the traditional biomedical models. As a result, the social model of nursing and healthcare that emerged in the 20th century highlighted the social aspects of treatment and nursing. While the biomedical model basically viewed all patients suffering from the same illness or disease as the same population, the social model emphasized the individual difference in religious, cultural, ethnic background of the patients (Wesley, 1995). The holistic principles promoted by the social models perfectly complement for the drawbacks of the biomedical models.
The modern models of nursing aim to find the most effective combination of the biomedical and social models. Dorothy Johnson's Behavioural System Model "focuses on a behavioural system (the patient), its subsystems, and its environment" (Polit, & Hungler, 1995: 102). Johnson views the patient's behaviours are the primary objects of nursing analysis claiming the human being has seven behavioural subsystems: attachment, dependency, ingestive, eliminative, sexual, aggressive, and achievement. Each of these subsystems arises from a drive related to a desired goal, a set of likely responses specific to the individual, a group of choices as to effective responses, and the observable outcomes known as behaviour (Johnson, 1990). Some claim that nursing diagnoses in the Behavioural System Model may deal with insufficiency, discrepancy, incompatibility, or dominance
Another well-known model of nursing