Skip to main content
. Author manuscript; available in PMC: 2018 Jul 1.
Published in final edited form as: Epidemiology. 2017 Jul;28(4):562–566. doi: 10.1097/EDE.0000000000000665

Table 2.

Summary of the G-computation (Gcomp.) and inverse probability weighting (IPW) for estimation of the population effect (in %) over 5000 simulations with biased sampling of n=2000 units. Performance of the unadjusted estimator (Unadj.) for the sample and population effects are also shown. The true value of the sample effect changes with each study enrollment (Table 1); population effect is −5.5%.

Average Bias Variance MSE Coveragea
Unadj. for SATE −10.4 −0.01 0.04 0.04 95.0
Unadj. for PATE −10.4 −4.9 0.04 0.29 30.8
Gcomp. for PATE −5.5 −0.06 0.05 0.05 95.0
IPW for PATE −5.5 −0.06 0.06 0.06 95.0

MSE indicates mean squared error, SATE sample average treatment effect, PATE population average treatment effect, IPW inverse probability weighting.

a

Coverage: 95% confidence interval coverage, constructed using the true (vs. estimated) variance.