On the semiparametric efficiency of the Scott-Wild estimator under choice-based and two-phase sampling (Q933896)

Summary: Using a projection approach, we obtain an asymptotic information bound for estimates of parameters in general regression models under choice-based and two-phase outcome-dependent sampling. The asymptotic variances of the semiparametric estimates of \textit{A. J. Scott} and \textit{C. J. Wild} [Biometrika 84, No.~1, 57--71 (1997; Zbl 1058.62505); J. Stat. Plann. Inference 96, No.~1, 3--27 (2001; Zbl 0976.62105)] are compared to these bounds and the estimates are found to be fully efficient.