Probability-based panel: This is a national panel that was recruited through random sampling of a population-wide database. In the United States, today most of these panels are recruited by random sampling from residential addresses or phone numbers. Data collection is usually done online. Some panels, however, interview a very small number of respondents (usually 5% or less) in an offline mode like a live phone. These panels are “probability-based” because the chance that each address or phone number is selected is known. The chance that each person selected will join the panel, or complete surveys after joining the panel, is unknown.
Sample online opt-in These samples are recruited using a variety of methods that are sometimes referred to as “convenience sampling.” Respondents are not selected randomly from the population but are recruited from a variety of online sources such as ads on social media or search engines, websites offering rewards in exchange for survey participation, or self-enrollment in an opt-in panel. Some opt-in sample are sourced from panels (or multiple panel), while…
