Section outline

    • This module describes the differences between a clinical trial, an observational cohort study, and studies that evaluate new medical tests. Strengths and weaknesses of each study design are discussed as well as how to select a study design based on the study aims and available data.  Examples from the medical literature are used to demonstrate how the choice of study design impacts study results and conclusions.

    • objective Objectives

    • Observational StudiesRandomized Blinded TrialsStudies of Medical Tests
      • Define cohort studies.
      • Distinguish between prospective and retrospective cohorts.
      • Explain the nested case-control design and strategy.
      • Describe the multiple-cohort design.
      • Define cross-sectional studies.
      • Explain why cross-sectional studies yield weaker evidence for causality than cohort studies.
      • Define case-control studies and their benefits and problems.
      • Describe case-crossover studies.
      • Define randomized blinded trials.
      • Explain how to design RBTs.
      • Describe how to choose the intervention and control conditions.
      • Describe how to define outcomes and adverse effects.
      • Describe how to select participants.
      • Describe how to measure baseline and outcome variables.
      • Evaluate approaches to randomizing and blinding.
      • Understand the definition of studies of a medical tests and how these studies differ from therapeutic intervention trials or studies to assess causality.

      •  Explain how to select subjects for a study of a medical test.

      • Understand how to measure reproducibility of a test including use of kappa and the coefficient of variation.

      • Define key metrics to use in studies that assess the accuracy of a diagnostic test including sensitivity, specificity, predictive value, ROC curves, and likelihood ratios.

      • Understand how to design studies of clinical prediction rules and the associated limitations and challenges with this design.

    • Readings Reading

    • In Designing Clinical Research, 4th Edition, by Hulley et al.

      Read all of the following:

      • Chapters 7, Cross-Sectional and Cohort Studies
      • Chapter 8, Case Control Studies
      • Chapter 10, Randomized Blinded Trials

      Also choose at least one of the following to read:

      • Chapter 11, Alternate Trial Designs and Implementation Issues
      • Chapter 12, Studies of Medical Tests
      • Chapter 13, Research Using Existing Data

    • Optional Reading: Research Designs for Studies Evaluating the Effectiveness of Change and Improvement Strategies (optional) URL

      This article describes some alternate and quasi-experimental study designs to consider if you're interested in studying the effectiveness of an intervention implemented in a real-world setting, where it may not be possible to achieve ideal experimental conditions.

    • Lecture Lecture

    • Observational Study Designs Slides File
    • Randomized Trials Slides File
    • Studies of Medical Tests Slides File

    • Small Group Sections

    • Small group sections for this module take place on Monday during the second week of each track (see section roster for your assigned time and Zoom link)

    • Assignments Assignments

    • STUDY DESIGN ASSIGNMENT - Due by Thursday before 5 PM during the second week (email to section leader) Forum
      Students must
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    • Exercises Optional Exercises

    • Optional Exercises -- Designing Cross-Sectional and Case-Control Studies Quiz
      Not available unless: You belong to Registered Student Only
    • Optional Exercises -- Designing a Cohort Study Quiz
      Not available unless: You belong to Registered Student Only
    • Optional Exercise -- Name That Study Design Quiz
      Not available unless: You belong to Registered Student Only
    • Optional Exercise -- Designing a Randomized Blinded Trial Quiz
      Not available unless: You belong to Registered Student Only
    • Optional Exercises -- Studies of Medical Tests Quiz
      Not available unless: You belong to Registered Student Only