There are times when an experimental study would not disclose an accurate answer to the research question, especially when the variables cannot be controlled. Other times, an experimental study would be unethical because the study could cause harm to the participants. In these cases, you might design an observational study, where you would observe the variables and collect data as you make your observations.

In this Discussion, you will propose a design for an observational study.

To prepare: For this Discussion:

  • Review the comparisons of observational study designs provided in table 7–6 on pages 360–361 in the text. Pay particular attention to the advantages and disadvantages of case-control and cohort studies.
  • Choose a public health problem that interests you.
  • Determine a research question about the public health problem that you would like the study to answer.
  • Consider how you might design an observational study (case-control study or cohort study) that could answer the study question.

Post a comprehensive contribution that proposes an observational study design for your chosen topic. Your answer should include your responses to the following questions:

  • What exposure and outcome variables will you measure?
  • Who will be the participants?
  • If you chose a case-control study design, what are your selection criteria for cases and controls?
  • If you chose a cohort study, what type of cohort study have you selected? Why did you select that approach?




Epidemiology for Public Health Practice
Chapter 6, "Study Designs: Ecologic, Cross-Sectional, Case-Control"The authors compare and contrast various types of observational analytic studies. The odds ratio, which is the measure of association used in case control studies, is also described.
Chapter 7, "Study Design: Cohort Studies"This chapter provides an overview of cohort studies and distinguishes them from other study designs. While a case control study begins with an outcome and seeks data on one or more exposures, cohort studies begin with an exposure and seek data on one or more outcomes. Research questions that particularly lend themselves to cohort studies are also presented. The concept of relative risk, the measure of association often used in cohort studies, is also covered in this chapter.

Optional Resources

Meirik, O. (September, 2008). Cohort and case-control studies. World Health Organization. Retrieved from:

Focus your attention on the "Advantages and Disadvantages of Cohort and Case-Control Studies" section of this article.
    • 3 years ago
    • 10