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Timing Of Randomization
The timing of randomization
can have implications for baseline and outcome measures, especially
when more subtle issues emerge when adhering to the rigorous design
of an RCT that evaluates a clinical intervention for a condition
such as TMD.
If pain or some other
symptom state is the critical outcome measure, it is obviously
necessary to insure that patients in the experimental and control
groups do have pain when the study begins--that is, at baseline.
The case history in
the example below illustrates some possibly dire consequences
of poor timing of randomization.
Problem
5.2
When attempting
to design a clinical study to examine the efficacy of an anti-depressant
medication for TMD pain, eager study recruiters screened patients
for levels of pain and depression and then sent baseline measures
home with patients, to be returned by mail, without rigorously
attempting to evaluate both the patient's true willingness to
participate in the study and the likely level of patient cooperation.
The results of these recruiting activities looked, at first glance,
like recruitment was going well and subject enrollment would not
be a problem. However, an unavoidable interval of about three
weeks was necessary before all baseline measures could be gathered
and when patients were finally randomized to experimental and
control groups.
Question
5.2.1
What are some possible
dire consequences for this case history?
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