Blending Probability and Non-Probability Samples Using Calibration Techniques

• Activity Number: 390
• Type: Roundtables
• Date/Time: Tuesday, August 6, 2013 : 12:30 PM to 1:50 PM
• Sponsor: Social Statistics Section
• Author(s): Charles DiSogra*+ and Curtiss L. Cobb
• Companies: Abt SRBI and GfK
• Keywords: Web panels ; Non-probability samples ; calibration

Abstract

Web panels recruited through probability samples (e.g., ABS) are generally limited in size due to recruitment costs. Properly constructed, these panels can be an ideal generalizable sample for rapid web surveys. To overcome their small size to be able to meet larger sample requirements, it has been demonstrated that an appropriate quota sample drawn from one or more non-probability opt-in Internet panels may be used to supplement the probability sample and combined data calibrated to approximate the probability sample's estimates. Variables that effectively discriminate between these probability and non-probability samples are used in the calibration weighting. Based on experience at GfK/Knowledge Networks with KnowledgePanel, the speaker will discuss the methodology and feasibility of calibrating blended samples from different sources. This methodology can be used with any single-purpose probability-recruited web panel. Alternatively, if mode effects are ignorable, any probability telephone, in-person, or mail sample might also potentially benefit from a non-probability web sample supplement as a cost-saving function. These applications are for discussion.