“'Public opinion and survey research'” refers to the systematic collection and analysis of information from or about individuals, groups, or organizations concerning their behaviors, cognitions, attitudes or other characteristics. It encompasses both quantitative and qualitative research methods, traditional or emerging" (American Association for Public Opinion Research).
The following are well-known sources for finding public opinion.
The first video in Pew Research Center's "Methods 101" series helps explain random sampling – a concept that lies at the heart of all probability-based survey research – and why it’s important (2:25).
Watch the other videos in the series below.