Seminar
Sunghee Lee Ph.D
"Estimation for Volunteer Panel Web Surveys Using Propensity Score Adjustment and Calibration Adjustment"
Propensity score adjustment (PSA) has been suggested as an approach to adjustment for volunteer panel Web survey data. PSA attempts to decrease, if not remove, the biases arising from noncoverage, nonprobability sampling, and nonresponse in volunteer panel Web surveys. Although PSA is as an appealing method, its application in Web survey practice is not well documented, and its effectiveness is not well understood. This study attempts to provide an overview of the PSA application by demystifying its performance for Web surveys, extends its application by combining it with calibration adjustment and examines variance estimation methods. Findings are five-fold: (a) PSA decreases bias but increases variance, (b) it is critical to include covariates that are highly related to the study outcomes, (c) an addition of calibration to PSA is more effective than using PSA only, (d) bias reduction is crucial for valid variance estimation and (e) the replication variance estimation method is favored over the other approaches.
