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3 Cards in this Set
- Front
- Back
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Describe the difference between observational and experimental clinical research studies.
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Observational studies do not have an actively produced exposure, while experimental research studies do.
Instead, observational studies measure exposures from the past or from those that are preexisting. |
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Distinguish internal validity from external validity (generalizability) in a research study
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Internal validity is when the differences between the control and experimental group are accounted for in the hypothesis. The focus is on deciding whether the results and conclusions of the study are valid. Internal validity is primarily an assessment of the methodological quality of the study. The three primary threats to internal validity are chance, bias, and confounding variables.
External validity ensures that the results of the experiment may be extrapolated to the population being examined. |
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Describe the essential features, strengths, and limitations of major study designs (cross sectional; case control; cohort; randomized controlled trial)
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Cross-sectional: taking measurements of exposures/outcomes at a single point in time; + cheap, quick, measures disease prevalence and potential risks; cannot measure disease incidence, purely associative
Case Control: only looking at a particular subset of the population and then matching them with appropriate controls; +cheap, less time, less subjects, efficient for studying rare diseases; can't calculate disease prevalence, need to have good matching, exposure data not always complete or reliable. Cohort: entire population; + measures disease prevalence, more accurate than case-control, good for looking at rare exposures; lengthy, $$$, follow-up loss; can be hurt by confounders Randomized Controlled Trial: most rigorous, tries to prove causality or strong associations; - $$$, lengthy, generalizability of populations is often poor, ethical problems with human experiments |
