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Choosing controls

QuestionAnswer
What are the three ways of choosing controls? 1) Nested case control 2) Case-cohort or case-base sampling 3) Risk-set sampling or density sampling
How are controls selected from a nested case-control study? Controls are selected from those who do not experience the outcome during follow-up of a cohort study.
Controls selected using which method gives an estimate of exposure odds of the survivors? Nested case-control
What does the exposure odds of survivors estimate? OR in the base population
How are controls selected using case-cohort or case-base sampling? Controls are selected from entire base population (those at-risk at beginning of follow-up)
Controls selected using which method gives an estimate of exposure odds in the base population of person at risk at start of followup? Case-cohort or case-base sampling
What does the exposure odds in the base population of person at risk at start of followup estimate? Risk ratio in the base population
How are controls selected using risk-set sampling or density sampling? Controls are selected longitudinally throughout the course of the study.
Controls selected using which method gives an estimate of exposure odds in the study base (i.e., person-time at risk)? Risk-set sampling or density sampling
What does the exposure odds in the study base (i.e., person-time at risk) estimate? Rate ratio in the base population
Which method of selecting controls is used in most case-control studies? Density sapling (with matching on a time variable such as calendar time or age) and thus estimate the rate ratio without the need for any rare disease assumption.
Created by: AlneciaPHS