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Types of clinical studies. Thomas Abraham. Three broad types of studies: used for different purposes. Observational (observe groups of people, gather data, but does not make any kind of intervention) Experimental studies ( makes an intervention)
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Types of clinical studies Thomas Abraham
Three broad types of studies: used for different purposes • Observational (observe groups of people, gather data, but does not make any kind of intervention) • Experimental studies ( makes an intervention) • Meta studies: takes data from a large number of studies and compares them, providing results that are stronger than individual studies
Observational studies 1. Cross sectional ( measures or surveys data at a point in time) Eg: Opinion survey of nurses in Hong Kong about H1N1 vaccination; measuring obesity in teenagers • Typically used to study prevalance of a disease or condition ( not causes of a disease or condition)
Observational Studies 2. ) Case control studies-Patients with a particular disease or condition are matched with a similar group of people without the disease, and then data is collected from both groups about past exposure or behaviour. • Cannot really determine cause and effect, but useful for generating hypotheses based on the statistical associations
Observational studies 3. Cohort studies: A group of people without the disease being studied are chosen, their habits, or other variables, are recorded over a long period of time, to see who develops the disease and who does not. Associations are then made between habits and the disease. • This is the strongest observational method for trying to determine cause and effect
Experimental studies • Randomised controlled trial: gold standard of causality • Used to evaluate new treatments • Subjects are randomly allocated to intervention (gets new treatment and control( does not get new treatment) groups • Both groups should be as similar as possible • Double blind= neither subject nor researchers know who is getting what
Meta Studies • Looks the results of a wide range of published studies; regarded as high evidence value
Evaluating studies • Is it still at the animal or laboratory stage, or human stage? • Where published? peer reviewed journal, scientific meeting or press release/conference? • How big were the numbers tested? • How relevant are the findings-is it of immediate benefit for people • What will it cost? • Conflicts of interest
How big were the numbers tested? • How relevant are the findings-is it of immediate benefit for people • What will it cost? • Conflicts of interest