MCQ MAHE 2000 PSM Answer 18

• Identify people who do and don’t have the disease of interest, then examine their pasts to see if they had a particular exposure.
• Limitations: Cannot calculate incidence! A common subject for trick questions on exams. You also cannot calculate anything else with a “rate” in it, such as AR or PAR. Can calculate AR% and PAR%.
• Can calculate odds ratio to estimate RR. Create a table, use AD/BC formula. Remember, OR approximates RR when a disease is rare. As prevalence of the disease increases in your population, OR becomes a less accurate measurement.
• Do not use OR in a disease outbreak (the disease is not rare in that population).
• How to select your controls: They must be different from the cases in that they do not have the disease; they should be similar to the cases in every other way possible; you don’t know whether the cases or the controls have had your exposure of interest until you survey them.
• Case-cohort study: From a larger cohort, select cases and controls come randomly from the baseline cohort.
• Nested case-control study: From a larger cohort, select cases and controls come randomly from members of the cohort when the new cases occur.

Category: MAHE 2000 MCQs