Figure 4

(a) Graph describing a MAR missingness process. X and Y are fully observed variables, Z is partially observed and ${Z}^{\ast }$ is a proxy for Z. ${R}_{z}$ is a binary variable that acts as a switch: ${Z}^{\ast }=Z$ when ${R}_{z}=0$ and ${Z}^{\ast }=m$ when ${R}_{z}=1$. (b) Graph representing a MNAR process. (The proxies ${Z}^{\ast },{X}^{\ast }$, and ${Y}^{\ast }$ are not shown.)