Abstract
Methodologists have traditionally categorized randomized controlled trials (RCTs)
as explanatory (representing the ideal setting) and pragmatic (representing the real-world
setting). Although this framework has greatly advanced the design and interpretation
of RCTs, current interpretations of the explanatory-pragmatic framework suffer from
two major limitations. First, they confound purpose with structure. Second, they ignore
the varying perspective of those using RCT results to make clinical and policy decisions
in the real world. The purpose of a trial should determine researchers' choices regarding
the trial's structure and the structure of a trial determines the extent to which
a decision maker will find the results useful. In this article, we introduce two terms
that refer explicitly to the purpose of a trial: A trial is mechanistic to the extent that it addresses a biological relationship. In contrast, a trial is
practical to the extent that it provides comprehensive information that bears directly on specific
health care decisions. This revised framework facilitates investigators' choice of
optimal trial design, and clinicians' optimal interpretation of RCT results. If our
goal is clinical trials most relevant to individual patient decision making, we will
eschew the use of trials that enroll patients unlikely to benefit (e.g., those with
uncertain diagnosis); those likely to be noncompliant; treated by practitioners whose
differing expertise is likely to result in differing outcomes; and permitting cointerventions
that are likely to influence treatment effectiveness—i.e., the conventional pragmatic
trial. Instead we will design, implement, and apply the results of practical trials
to our patients.
Keywords
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Article info
Publication history
Published online: May 13, 2008
Accepted:
February 13,
2008
Identification
Copyright
© 2009 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
