QUICK REVIEW: Research design is the overall plan for a study. And…there are 2 main types of design: 1) Non-experiments in which the researcher observes and documents what exists,

and 2) Experiments when the researcher tries out an intervention and measures outcomes.

NEW INFO: Two non-experimental research designs that are often confused with one another are: 1) cohort studies & 2) case studies. Epidemiologists often use these designs to study large populations.

In a cohort study, a group of participants, who were exposed to a presumed cause of disease or injury, are followed into the future (prospectively) to identify emerging health issues. Researchers may also look at their past (retrospectively) to determine the amount of exposure that is related to health outcomes.

In contrast, in a case controlled study, participants with a disease or condition (cases) and others without it (controls) are followed retrospectively to compare their exposure to a presumed cause.

EXAMPLES?

1. Martinez-Calderon et al (2017 ) Influence of psychological factors on the prognosis of chronic shoulder pain: protocol for a prospective cohort study. BMJ Open, 7. doi: 10.1136/bmjopen-2016-012822
2. Smith et al (2019). An outbreak of hepatitis A in Canada: The use of a control bank to conduct a case-control study. Epidemiology & Infection, 147. doi: https://doi.org/10.1017/S0950268819001870

CRITICAL THINKING: Do you work with a group that has an interesting past of exposure to some potential cause of disease or injury? Which of the above designs do you find more appealing and why?