The E-value in epidemiology is used to assess unmeasured confounding. If an observed RR of 2.5 has an E-value of 4.5, what does this mean?
- A An unmeasured confounder would need an association of at least 4.5 with both exposure and outcome to fully explain away the observed RR ✓
- B The study requires at least 4.5 times more participants to confirm the finding
- C The relative risk would be reduced to 1.0 if 4.5 confounders were adjusted for
- D There is a 4.5-fold excess risk attributable to effect modification
Correct answer: A. An unmeasured confounder would need an association of at least 4.5 with both exposure and outcome to fully explain away the observed RR
Explanation
The E-value is the minimum strength of association (on the RR scale) that an unmeasured confounder would need to have with both the exposure and the outcome, beyond the measured confounders, to fully explain away the observed association. A high E-value (4.5) means the result is relatively robust to unmeasured confounding; a low E-value near 1.0 means the association could easily be explained by a weak unmeasured confounder.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.