Web surveys can be conducted relatively fast and at relatively low cost. However, Web surveys are often conducted with nonprobability samples and, therefore, a major concern is generalizability. There are two main approaches to address this concern: One, find a way to conduct Web surveys on probability samples without losing most of the cost and speed advantages (e.g., by using mixed-mode approaches or probability-based panel surveys). Two, make adjustments (e.g., propensity scoring, post-stratification, GREG) to nonprobability samples using auxiliary variables. We review both of these approaches as well as lesser-known ones such as respondent-driven sampling. There are many different ways Web surveys can solve the challenge of generalizability. Rather than adopting a one-size-fits-all approach, we conclude that the choice of approach should be commensurate with the purpose of the study.
"Options for Conducting Web Surveys." Statist. Sci. 32 (2) 279 - 292, May 2017. https://doi.org/10.1214/16-STS597