Are graded clinical signs more reliable than dichotomized?

Clinical diagnosis is often based on the presence of clinical signs,
like tenderness. These signs present with varying intensity and the
judgement if a sign is present or not is a subjective assessment with
no objective definition.

Instead of dichotomising these clinical signs I think that a grading
of the intensity of the sign must retain more of the diagnostic
information, ie instead of deciding on if tenderness is present or not
the tendderness is graded absent, slight, moderate or intense.

One problem is of course that there is no definition for the grades of
the variable. However the dichotomised variable has the same problem
and I assume that the agreement between two examiners will be larger
if graded variables are used instead of dichotomised.

I have not found any previous research on this subject and would be
very happy for your input.


Roland Andersson
Surgeon
Sweden

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