Thank you to Dr Axelrod and Dr Horwitz for two amazing lectures recently!
For Dr Axelrod’s lecture:
Here are the highlights from Dr Horwitz’s lecture:

All of the above biases are present in observational studies, but eliminated in RCT
Cohort vs Case Control Studies
Cohort
Risk ratio: Inc dz / everyone exposud vs (Inc of CA among /not exposed )
Case control
Case control easier when incidence is low, and when there is a long time bw exposure and development or dx of illness
Odds Ratio: Antecedent exposure / diseased pts vs antecedent exposure / non diseased (control)
Confounding variables
- Exposure A is related to another exposure X, which may affect incidence of dz
- Intermediate confounding: Bias introduced in the intermediate between exposure and outcome state
- Loss to follow up
Types of Research
Change (Causal) Research
- Harm: etiologic or risk factor (RR or OR)
- Diagnostic accuracy
- Prognosis
- Therapeutic: Real world evidence vs RCT
Conformity / Consistency Research
- Quality of Care
- Inter- and Intra- Observer Variation