Question: You have been hired as a consultant to advise a non-profit organization’s research team about which study design would be appropriate as they seek funding to address the following research areas:

• To determine the relationship between exposure to in-home treated drinking water and diarrhea among children in three neighboring towns of Sierra Leone.
• To survey the prevalence of STIs among male college students at 10 universities in the United States. Five of these universities are in an urban area and exposed to city-wide and state-wide campaigns about sexual health while the other five do not.
• To study whether neighborhood factors such as number of grocery stores and number of liquor stores have an impact of health status.

For each research area, select the most appropriate study design. Discuss the strengths and weaknesses of the selected study design. How does this design optimize internal validity? How does this design optimize external validity?

Answer: Cohort studies are suitable for such a research design as they establish causation…….