The main use of the Neuman Model in practice and in research is that
its concentric layers allow for a simple classification of how severe
a problem is. For example, since the line of normal defense represents
dynamic balance, it represents homeostasis, and thus a lack of stress.
If a stress response is perceived by the patient or assessed by the nurse,
then there has been an invasion of the normal line of defense and a major
contraction of the flexible line of defense. Infection or other invasion
of the lines of resistance indicates failure of both lines of defense.
Thus, the level of insult can be quantified allowing for graduated interventions.
Furthermore each person variable can be operationalized and the relationship
to the normal line of defense or stress response can be analyzed. The
drawback of this is that there is no way to know whether our operationalization
of the person variables is a good representation of the underlying theoretical
For example, Eileen Gigliotti published a research article in 1999 based
on the Neuman Systems Model. The study investigated the relationship of
multiple role stress to the psychological and sociocultural variables
of the flexible line of defense. If multiple role stress had occurred,
then the normal line of defense had been invaded. Questionnaire instruments
were used to operationalize the psychological component with perceived
role as a student and as a mother; the sociocultural component with social
support, the normal line of defense as perceived multiple role stress.
Upon analysis, no conclusions could be made about the normal line of
defense simply on the basis of the psychological component and sociocultural
component. By dichotomizing the data by median age, however, a relationship
between them could be described. Thus the relationship between the normal
line of defense and the psychological and sociocultural components could
only be described by taking into account the developmental component.
It indicates that the components of the flexible line of defense interact
in very complex ways and it may be difficult and dangerous to overgeneralize