Introduction
In 2013, more than half of global research revenues were generated by online surveys (ESOMAR, 2013), and "while the government and academic sectors of the public opinion industry have steadfastly insisted on retaining probability methods for virtually all surveys, the commercial sector has adopted non-probability methods for most survey data collection" (Boyle, Iachan, Freedner- Maguire, & Fakhouri, 2017, p. 7). The use of online panels is expected to continue as a main methodology for market and social research professionals (GreenBook Research Industry Trends Report, 2019). But online panels are problematic because—being non-probability samples of people who have voluntarily signed...