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Types of Clinical Trials PDF Print
Sunday, 08 October 2006 15:03

Types of studies
Generally, experts conduct three types of studies: descriptive, observational and controlled trials.

Descriptive Studies: As the name implies, a description of a study group or population can be revealed from this type of trial. For example, researchers may report that all women in their study population who experience hot flashes have brown hair. In this case, brown hair does not necessarily cause hot flashes but there may be an interesting correlation between hot flashes and hair color.

Observational Studies: Researchers can observe people in their everyday environments in order to determine the group’s nature or qualities. Usually, observational studies are given to people over extended periods of time. For example, if researchers are interested in learning about black cohosh for treating menopausal symptoms, they could make an observational study. Researchers could interview participants about their lifestyles, medical histories, existing medical conditions and medications. They may notice correlations between the black cohosh therapy and other factors. But researchers cannot necessarily make conclusions about what caused the correlations. In this type of study, there is no real control in place.

Controlled Trials: These types of studies focus on the causes of particular effects and determine the effectiveness of a therapy. Controlled studies break up a study population into two groups. The first group uses the therapy that is being studied. The second group takes a placebo (an inactive preparation used as a control in an experiment). The purpose of a controlled trial is to detect a difference between the treated and control groups. Types of controlled trials include randomized trials, open trials and blind trials (single-blind, double-blind, triple-blind).

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Last Updated on Friday, 28 October 2011 15:19

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