Dissertation Defense Substitution of Nonresponding Units in Probability Sampling

The substitution of a nonresponding unit with one not originally selected in the sample is a commonly used method for dealing with unit nonresponse. Although frequently used in practice, substitution is largely neglected in the survey sampling literature. To date, few studies have attempted to develop a formal framework for describing and evaluating substitution methods, and little research has been done to improve estimates obtained through the use of substitution as a nonresponse adjustment procedure. This dissertation presents the results from three research studies conducted to enhance our understanding of substitution methods and develop new procedures to improve them.