Chapter 11 Notes
Absolute Risk: Incidence of disease across the whole population. Doesn't compare subpopulations; like exposed vs. not exposed.
Relative Risk: Incidence of disease in exposed population/Incidence of diesease in non-exposed population
Can only be calculated for a cohort study design.
-Positive: possibly casual association between exposure and disease RR is greater than 1.
-Negative association between exposure and disease. (ex: vaccine protection against disease to protect) RR is less than 1.
Odds Ratio: Good at estimating the RR when a cohort study was not used. It's an estimate of RR that can be calculated with data from a case-control or cross sectional study design.
Odds= Probability of the thing happening(P) / Probability of thing not happening (1-P).
Odds= ad / bc
-Only a good estimate of RR if:
1.) Survey: Cases are representative of the underlying population.
2.) If controls are representative of the underlying population
3.) Within underlying population disease is rare.
