Healthcare and Medicine Reference
The evaluation of the internal validity (how does it detect disease as such)
or the external validity (how does it work from one individual to another) of
diagnostic methods must be considered both for screening and for reference
diagnostic tests. Anchoring (premature closure of the diagnostic workup),
ordering and triage-related fallacies, ignoring Bayesian diagnostic prior/
posterior/revised probabilities or rhetorical manipulations are some examples
of diagnostic reasoning to avoid and correct.
Treatment must be seen as a matter of intervention at various levels of
prevention, health protection, and health promotion. Controlled clinical
trials and their alternatives focus on the demonstration of a causal relation-
ship between some beneficial factor and improvement in health and disease
based on the rules outlined in Chapter 2. The best evidence according to
evidence-based medicine rules is sought here. Ignoring webs of causes and
consequences, appeals to authorities or tradition, or actions at any price are
just some of the fallacies to know, prevent, and rectify.
Prognosis refers to a rather longitudinal (over time) study of multiple
beneficial or noxious factors having both good and bad multiple conse-
quences on what happened or will happen once the disease is acquired.
Prognostic factors and markers often differ from risk factors and markers.
They are the subjects of “survival”-type studies, proportional hazard (the
impact of multiple prognostic factors) evaluations, and other methods. Case
fatality, response to treatment rates, remissions, relapses, disease gradient,
and spectrum may be in focus. Types of reasoning and argumentation are
common to some of the other above-mentioned domains of clinical activity.
Oversimplifications, divisions (whole entities and their parts), or misleading
uses of statistics are additional fallacies to avoid.
General rules of reasoning, critical thinking, and decision making apply
to all steps and stages of clinical work and care with individual patients
as well as to the management, prevention, and control of the disease and
health at community level.