Understanding Clinical Trial Design - Research Advocacy Network

UNDERSTANDING CLINICAL TRIAL DESIGN: A TUTORIAL FOR RESEARCH ADVOCATES
Intervention The act or instance of intervening. In a clinical trial, an
experimental or investigational intervention is compared
to a comparison or control intervention. The
interventions are often different treatment drugs, but
may simple entail different schedules of drug
administration, supportive therapies, etc.
Investigational A new drug, biological drug, or combination that is used
Treatment in a clinical investigation.
In Vitro In the laboratory (outside the body). The opposite of in
vivo (in the body).
In Vivo In the body. The opposite of in vitro (outside the body
or in the laboratory). Applies to both human and other
animal bodies.
Likelihood Ratio In Bayesian inference, the ratio between the probability
of an observation or datum conditional on a hypothesis
(numerator) and the probability of the same observation
or datum conditional on an alternative hypothesis
(denominator).
Mean Measure of central tendency. Equally weighs all outcomes,
and can be heavily influenced by outliers.
Computationally, the mean is equal to the sum of
outcomes, divided by the sample size.
Median Measure of central tendency in which half of the
outcomes are above and half below. The median is not
affected by outliers.
Meta-analysis The process of combining the data from a number of
independent studies (usually drawn from published
literature) and synthesizing summaries and conclusions
addressing a particular issue. It aims to utilize the
increased power of pooled data to clarify the state of
knowledge on that issue. Meta analysis is often used in
systematic reviews of studies of medical therapies to
evaluate therapeutic effectiveness.
Multi-Stage Trial Trials in which later stages of the trial are dependent up
Design what happens in earlier stages. An example of a twostage
trial design is the randomized discontinuation
design where a patient’s treatment may be changed in
the second stage of the trial, depending on the progress
of the disease during the first stage.
Non-inferiority Trial A clinical trial designed to evaluate whether an
experimental treatment is similar to a control treatment,
by an appropriate definition of similarity. A one-sided
(one-tailed) test of similarity is used.
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