RESEARCH METHODOLOGY POSTER PRESENTATION ABSTRACTS
Please note: All posters will be displayed in
Salons 10-12.
THURSDAY, 5:30-6:15 PM
Walach H, Jonas W, Lewith G, Fonnebo V, Falkenberg T.
Circular instead of hierarchical: methodological principles
for evaluating CAM and other complex interventions.
University of Northampton, School of Social Sciences
& Samueli Institute, European Office Harald.walach@northampton.ac.uk
The implicit reasoning behind evaluating medical interventions
is that a hierarchy of methods exists which successively produce improved
and therefore more rigorous evidence based medicine upon which to make
clinical decisions. At the foundation of this hierarchy are case studies,
retrospective and prospective case series, then cohort studies with
historical and concomitant non-randomized controls. Open-label randomized
controlled studies (RCTs), and finally blinded, placebo-controlled RCTs.
The latter offer most internal validity. Rigorous RCTs remove bias.
Evidence from RCTs forms the basis of meta-analyses and systematic reviews.
This implicit hierarchy, founded on a pharmacological model of therapy,
is generalized to other interventions which may be complex and non-pharmacological
(healing, acupuncture and surgery). The hierarchical model is valid
for limited questions of efficacy, for instance for regulatory purposes
and newly devised products and pharmacological preparations. It is inadequate
for the evaluation of complex interventions such as complementary and
alternative medicine (CAM). This has to do with the essential tension
between internal validity (rigor and the removal of bias) and external
validity (generalizability). Instead of an Evidence Hierarchy, we propose
a Circular Model. This would imply a multiplicity of methods, using
different designs, counterbalancing their individual strengths and weaknesses
to arrive at pragmatic but equally rigorous evidence of significant
help in clinical and health systems innovation. Such evidence would
better inform national health care technology assessment agencies and
promote evidence based health sector reform globally compared to hierarchical
model information of limited generalizability.
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