For the simulated population, bias index of the El-Badry estimator as a function of the nonresponse rate at the last phase.

Curve of the bias index based on 10 000 simulations of the nonresponse mechanism, for L = 2(1)6, πz = 0.2, πm(i) = 0.85 for 1 ≤ i L, and πm(L) = 0(0.1)0.9 (black dots L = 2; white circles L = 3; black triangles down L = 4; white triangles up L = 5; black squares L = 6). Details in the text.