Lecture 11 Flashcards
What is a case-control study?
Separating your groups into those with the disease/outcome (case) and having a second group that is as closely related to the case group as possible but does not have the disease/outcome (control)
What information do you start with in a case-control study?
You know the disease/outcome
Are case-control studies prospective or retrospective?
ALWAYS retrospective
Name the major benefits of a case-control study
- Good for assessing multiple exposures to one outcome
- Useful when disease are rare
- Less expensive
- Useful when disease has long induction/latent period
What is the selection of cases defined by?
The investigator, using accurate, medically reliable, and efficient data
Which group is more difficult to select in a case-control study, case group or control group?
Control group…way controls are selected is major determinant in whether any conclusions are valid
T/F: Selection of control group can be a random accumulation of data.
False: Selection of control group must be a systematic, officially defined process
How can someone be a case and a control in the same study?
1) Can be associated with an outbreak investigation with multiple exposures
2) “Case-Crossover”- Have an acute change in risk of the outcome of interest (hazard period)
* Subjects are their own controls during the times they don’t have the acute risk
What is selection bias?
It is related to the way controls are chosen for the study
What are recall biases?
They are related to the amount/specificity that cases or controls recall past events DIFFERENTLY
(Cases more likely to recall)
What are the two matching schemes?
Individual Matching & Group Matching
What is individual matching?
Match individuals based on specific patient-based characteristics
*Used when each case has unique characteristics
What is group matching?
Proportion of cases and controls with identical characteristics are matched
*cases=41% males, controls=41% males
T/F: Always match anything that may be a risk factor.
F: NEVER match anything that may be a risk factor
What are nested case-control studies?
Studies conducted as part of a prospective cohort study.
*Subjects defined as “cases” are the ones from cohort that ended up with disease
