Propensity Score Weight Adjustment with Several Follow-Ups

• Activity Number: 496
• Type: Topic Contributed
• Date/Time: Wednesday, August 1, 2012 : 10:30 AM to 12:20 PM
• Sponsor: Section on Survey Research Methods
• Author(s): Jaekwang Kim*+ and Jongho Im
• Companies: Iowa State University and Iowa State University
• Keywords: nonignorable ; missing data ; unit nonresponse ; weighting

Abstract

Propensity score weighting adjustment is commonly used to handle nonresponse. When the response mechanism is non-ignorable in the sense that the response probability depends directly on the study variable, a follow-up sample is commonly used to obtain an unbiased estimator using the framework of two-phase sampling. In this two-phase sampling approach, the follow-up sample is assumed to respond completely. In practice, the follow-up sample is also subject to missingness. We consider the problem of propensity score weighting adjustment when there are several follow-ups and the final follow-up sample is also subject to missingness. We propose a novel approach, so-called reverse two-phase sampling, that makes use of the monotone structure of missing pattern and enables efficient estimation. The proposed method is more flexible than the existing methods and can be directly applicable to co