Behavioural sciences

Question 1

Describe a cross-sectional study.

Answer 1

• Collects data from a group of people to assess frequency of disease (and related risk factors) at a particular point in time. Asks, “What happened?”.
• Measures disease prevalance.
• Can show risk factor association with disease, but does not establish causality.

Question 2

Describe a case-control study.

Answer 2

• Compares a group of people with disease to a group without disease. Looks att prior exposure or risk factor. Asks “What happened?”
• Measures odds ratio (OR).“Patients with COPD had higher odds of a history of smoking than those without COPD.”

Question 3

Describe a cohort study.

Answer 3

• Compares a group with a given exposure or risk factor to a group without such exposure.
• Looks to see if exposure affects the likelihood of disease.
• Can be prospective (asks, “Who will develop disease?” or historical (asks, “Who developed the disease [exposed vs. nonexposed]?”
• Relative risk (RR)
• “Smokers had a higher risk of developing COPD than nonsmokers.”