Assignment task:
When taken as prescribed, PrEP is highly effective for preventing HIV.
1. If you randomly sample the sexually active general population and obtain PrEP and HIV status at the same time, your study design is:
cross-sectional, case-control, cohort, or a randomized clinical trial?
What is your measure of association: prevalence ratio or risk ratio?
2. If you randomly sample the from a sexually active non-HIV population taking PrEP and sexuall active non-HIV population not taking PrEP and follow subjects over time to see who develops HIV, your study design is:
cross-sectional, case-control, cohort, or a randomized clinical trial?
What is your measure of association: prevalence ratio or risk ratio?
3. If you randomize sexually active non-HIV subjects to either a PrEP or Placebo group; and follow them over time to see who develops HIV, your design is:
cross-sectional, case-control, cohort, or a randomized clinical trial?
What is your measure of association: prevalence ratio or risk ratio?
4. If you randomly sample the population of sexually active people with HIV and randomly sample sexually active people without HIV, and compare rates of exposure or PrEP in the past, your study design is
cross-sectional, case-control, cohort, or a randomized clinical trial?
What is your measure of association: prevalence ratio, risk ratio, or odds ratio?