1. Henly, Susan J. PhD, RN

Article Content

Who doesn't know the nature of nursing? It's all about people, and helping them to health as an asset for a good life. Nurses act in the present, in recognition of the past, to optimize future health for the individuals, families, and communities they serve. The best nursing care is characterized by appreciation of the uniqueness of each human health trajectory-the experienced course of health over time.


Emphasis on the individual in clinical practice stands in sharp contrast to variable-focused science. Examples abound. Stress influences perceived health status. Self-esteem buffers negative affect. Hypothermia generates morbidity. Social support enhances health. And so on. Variables actively influence one another, but the person has disappeared!


What is the status of "persons" in variable-focused science? Typically, research participants meet inclusion, exclusion, and randomization criteria to ensure that the sample will be representative of an identified population. The role of participants is that of interchangeable objects. The individuality so valued and protected in practice is lost in science. Ironically, investigators studying natural health-illness systems from a variable-centered perspective need dissimilarity among individuals in their studies, for without individual differences, no links among variables can be found!


Long ago now, Cattell (1966) introduced the "data box" to logically describe potential research perspectives. Drawers at the top, front, and side of the data box represent sampling people, variables, and occasions. The data box shows that a particular life experience cannot be described when the people-by-variables drawer, used in most nursing research, is opened. Rather, a single unique experience is described when a variables-by-occasions drawer is taken from the box to create a person-centered perspective. Opening additional variables-by-occasions drawers shows variation in the human experience. Recent advances in statistics have moved the data box from heuristic to practical tool for designing person-centered research. Today, multilevel models for change can be used to map and explain patterns of intra- and interindividual variability across the range of human circumstance (e.g., Singer & Willett, 2003).


Variables-by-occasions drawers are rarely opened by nurse scientists. When longitudinal approaches are taken, the richness of the individual experience is typically obscured by analytic methods that emphasize average change. The information is useful, and yet, what nurse ever cared for an average patient? The gold standard in practice is creating change to optimize health for a particular individual, family, or community. Nursing science will advance by incorporating a similar person-centered perspective.


The individual health trajectory is the heart of person-centered nursing science. Accurate and precise measurement, temporal design, and mathematical functions reflecting theory about change (hypotheses about health course) are combined to describe unique health trajectories. The models are challenging, but those who learn to decode and interpret their parameters gain insight about individual experience and its variations with the touching poignancy usually reserved for art.


Now is the time to find the person in dynamic (not static) nursing research.


Susan J. Henly, PhD, RN


Associate Editor


Methods Director, Minnesota Center for Health Trajectory Research




Cattell, R. B. (1966). The data box: Its ordering of total resources in terms of possible relational systems. In R. B. Cattell (Ed.), Handbook of multivariate experimental psychology (pp. 67-128). Chicago: Rand-McNally. [Context Link]


Singer, J. D., & Willett, J. B. (2003). Applied longitudinal data analysis. Oxford: Oxford University Press. [Context Link]