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  • 00:00


  • 00:01

    SPEAKER 1: We need to talk a little bit about the hierarchyof different studies.So generally speaking, study designsare grouped into a hierarchy of increasing quality,with those higher in the hierarchy showing a strongerassociation between exposure and outcome or treatment and cure.For a meta analysis, if the individual studies

  • 00:23

    SPEAKER 1 [continued]: utilized randomized controlled trials,combining several selected randomized controlled trialresults, will be the highest level of evidenceon the evidence hierarchy.This is followed by systematic reviews.Systematic reviews is where an analysisof all available studies on a topic are used.

  • 00:43

    SPEAKER 1 [continued]: They're not necessarily combined statistically,but a systematic review can give you different levelsof evidence on a certain topic.Next on the hierarchy is a randomized controlled trial.And I would also say that a really, reallylarge randomized controlled trial, a single trial,is also really, really good evidenceand should probably be up higher on this level here.

  • 01:05

    SPEAKER 1 [continued]: But an RCT avoids the confounding and recallbias associated with the cohort and case control studies.And finally, we have a case report, whichdue to its small number of patientslike maybe even one patient, the description of the patientin an article, it's placed at the bottom of the evidencehierarchy, really.


The hierarchy of study types in the method section of a scientific paper is discussed.

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The Methods: Hierarchy of Study Types

The hierarchy of study types in the method section of a scientific paper is discussed.

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