KNES 469 Lecture Notes - Lecture 4: Random Assignment, Randomized Controlled Trial
¡Cohort Studies: Strengths
§Can be used to define incidence and investigate potential causes of an outcome
before it occurs
§Time sequence strengthens inference that the factor may cause the outcome
¡Weaknesses
§Expensive – many subjects must be studied to observe outcome of interest
§Potential confounders
¡Case Control Studies: Strengths
§Useful for studying rare conditions
§Short duration & relatively inexpensive
§High yield of information from relatively few participants
§Useful for generating hypotheses
¡Weaknesses
§Increased susceptibility to bias:
▪Separate sampling of cases and controls
▪Retrospective measurement of predictor variables
§No way to estimate the excess risk of exposure
¡True experimental designs
¡Quasi-experimental designs
¡True experimental design:
