Healthcare and Medicine Reference
In-Depth Information
and systematic reviews
Experimental studies (clinical trials)
Observational analytical cohort studies
Observational analytical case-control studies
Observational descriptive studies of occurrence
Single clinical case reports and case series reports
Hearsays, anecdotes, narratives, plain ideas, opinions
This hierarchy of evidence may be valid for cause-effect relationships
and their ways of proof, but other domains requiring evidence may call for
another kind of “pyramid” or “hierarchy” of proof. For example, what might
a hierarchy of evidence be for physical examination or diagnosis whenever
the presence and absence of disease causing a positive or negative test result
is not of primary interest?
Grading evidence for types of research other than causal relationships
between noxious or beneficial factors in relation to health or disease such as in
the domain of validation of diagnostic tests requires a different approach. Besides
etiological considerations, any grading must have some sense and practical pur-
pose for decision making. Ideally, any stage or grade in a grading system must
differ from the other by expanding the understanding, changing the understand-
ing (different meanings such as different prognosis or differential diagnosis), or
modifying clinical decisions (treatment indications). Staging cancer in these terms
is well done; staging evidence is still more challenging in these practical terms.
From one situation to another, we must always find some mutually
acceptable language or specify differences between the participating profes-
sions and domains. The same holds true, for example, for a “case” and, in
Besides the evidence used in argumentation, the value and relevance
of the entire argumentative process depends on its conceptual frame-
work or framing . Within such a framework, we are always defining the
problem and its biological and physical setting, raising hypotheses about
what is going on, specifying objectives regarding what we intend to do
or how we intend to intervene, and at what we wish to arrive in gen-
eral and specific terms and dimensions. Our reasoning, understanding,
decisions and actions only have meaning and value if such a framework
is determined and known, preferably beforehand .
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