Wang, Weiwei; Scharfstein, Daniel; Tan, Zhiqiang; … - In: Journal of the Royal Statistical Society Series B 71 (2009) 5, pp. 947-969
We consider estimation of the causal effect of a treatment on an outcome from observational data collected in two phases. In the first phase, a simple random sample of individuals is drawn from a population. On these individuals, information is obtained on treatment, outcome and a few low...