The authors respond:

We welcome the opportunity to engage in discourse about middle-range theory. In our article we advocated the development of middle-range theories in addition to, not in opposition to or as a substitute for, the development of more specific theories. Empirically based concept development regarding the individual symptoms of dyspnea and fatigue provided the basis for moving to the broader scope and higher level of abstraction represented by the Theory of Unpleasant Symptoms. As Brown notes, such concept development yields valuable information about patients' symptom experiences. It is needed to guide symptom-specific measures and interventions. Continued empirical work and concept and theory development at the level of individual symptoms also provides the basis for continued amplification and refinement of the middle-range theory. We agree that it should continue.

Brown feels that a middle-range theory that encompasses several similar phenomena-in this case, unpleasant symptoms-may be less clinically useful than separate theories. Our experience has been that symptom-specific theory is too restrictive to be the sole focus of knowledge development. In keeping with nursing's holistic focus, clinical practice with ill patients almost always involves attending to more than one symptom at a time. The middle-range theory is clinically applicable because it goes beyond symptom-specific concepts and theories to stimulate thinking about common factors that may influence more than one symptom, the ways in which multiple symptoms interact with one another and affect performance, and interventions that would mitigate multiple symptoms.

To underscore the usefulness of theories that encompass multiple symptoms, we point out that while we were developing our Theory of Unpleasant Symptoms, another group of nurse scientists, the University of California, San Francisco, School of Nursing Symptom Management Faculty Group, [1] was developing a model to guide clinical practice in the management of a variety of symptoms.

Nursing theories are evaluated by several criteria, of which clinical usefulness is only one. Also important is a theory's ability to explain relevant phenomena in a parsimonious manner and to generate interesting scientific questions for study. It is our experience that a middle-range theory that highlights commonalities among symptoms and provides for the simultaneous experience of multiple symptoms (this aspect of the Theory of Unpleasant Symptoms is evolving) generates more interesting researchable questions than single-symptom approaches. The latter represent untapped scientific potential that can be most effectively maximized through the development of higher-level middle-range theories.

Elizabeth R. Lenz, PhD, RN, FAAN

Pennsylvania State University; Hershey Medical Center; Hershey, Pennsylvania

Frederick Suppe, PhD

University of Maryland, College Park; College Park, Maryland

Audrey G. Gift, PhD, RN, FAAN

University of Pennsylvania; Philadelphia, Pennsylvania

Linda C. Pugh, PhD, RN

Johns Hopkins University; Baltimore, Maryland

Renee A. Milligan, PhD

Georgetown University; Washington, DC

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