FIGURE 2.

Sample relative efficiencies (SREs) comparing ${\widehat{\xi }}_{\mathit{AIPW}}$ and ${\widehat{\xi }}_{\mathit{SRS}}$ to ${\widehat{\xi }}_{\mathit{IPW}}$ in terms of estimating γ₁, under different values of ρ. The sample relative efficiency is defined as $SR{E}_{\mathit{AIPW}:\mathit{IPW}}=\mathit{var}\left({\widehat{\xi }}_{\mathit{IPW}}\right)/\mathit{var}\left({\widehat{\xi }}_{\mathit{AIPW}}\right)$. AIPW, augmented IPW; IPW, inverse probability weighted