Table 2 Hypothetical results from an observational study
Risk factor value, xPopulation A, without interventionPopulation B, with interventionOdds ratio
rnRisk estimate*rnRisk estimate*
All levels25010000.2518010000.180.66
  • *Note that the risks in population A if they had had the intervention would be half the observed estimates, and in population B if they had not had the intervention would be twice the observed estimate.