Micro-range theory
Micro-range theory is the least formal and most tentative of the theoretical levels discussed in this article. It also is the most restrictive in terms of time and scope or application. However, its particularistic approach is invaluable for scientists and practitioners as they work to describe, organize, and test their ideas. We propose 2 levels of micro-range theory. At the higher level, micro-range theory is closely related to middle-range theory but is comprised of 1 or 2 major concepts, and its application frequently is limited to a particular event; for example, theories related to decubitus or catheter care.16
At the lower level, micro-range theory is defined as a set of working hypotheses or propositions.17 Scientists and practitioners use these working propositions to tentatively categorize, explain, or test health-related person-environment interactions. As such, they are not coded and entered into a formal theoretical system, but two examples serve to illustrate their invaluable contribution to science and practice. In the first example, scientists interested in developing and testing larger theoretical frameworks isolate and organize proposed conceptual relationships into propositions. The scientific literature is then used to investigate the relationships of the propositions and, if there is evidence for the truth of the relationships, to determine conceptual-empirical correspondence. In the second example, the clinician also uses propositions to identify, describe, and organize the working conceptual relationships in practice. The investigation, although identical in process to the scientist's, differs in terms of its scope and its generalizability; that is, the practitioner investigates more particular and immediate relationships in a smaller group of persons; or frequently, a single person. For instance, a nurse working on a general medical unit is assigned to admit an elderly patient with the medical diagnosis of chronic obstructive pulmonary disease. Before meeting the patient, and in attempt to organize knowledge, the nurse hypothesizes several possible conceptual relationships; for example, the patient's age and medical diagnosis limit the patient's functional status. The nurse then tests the working hypothesis through assessment and works to directly change the concepts' relationships through manipulation of the person-environment interaction.
Any discussion of micro-range theory must consider the term “practice theory.” We jump into the debate on what constitutes practice theory with the realization that numerous definitions exist and many authors consider micro-theory, as the most concrete and applicable of all theoretical levels, to be an equivalent term for practice theory.5 and 16 We believe this categorization limits the understanding of theoretical thinking in nursing and a broader definition of practice theory is more useful. Based on Ellis,18 and 19 who stated that all nursing knowledge ultimately is developed for practice, we maintain that all nursing theory, regardless of level, is practice theory.