The Feasibility of Obtaining Valid Inferences from Nonprobability Surveys

Survey data collection costs have risen to a point where many survey researchers are abandoning large, expensive probability-based samples in favor of less expensive nonprobability samples. The empirical literature suggests this strategy may be unwise for many reasons, among them probability samples tend to outperform nonprobability samples on accuracy when assessed against population benchmarks. Nevertheless, the attractive cost properties and convenience of nonprobability samples suggest they are here to stay. In this talk, we present recent empirical research on the strengths and weaknesses of nonprobability samples for survey inference. We present results from various sources of probability and nonprobability data and attempt to establish some middle ground between these two sampling streams.