Pew Research Center
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3 ways to correct a poll’s political balance: Party affiliation, past vote and voter file information
Pollsters vary in how they weight their survey samples on political characteristics, if at all. Their choices tend to be informed by factors such as the population being surveyed and the sample source (e.g., a list of all addresses in the United States or a list of registered voters), the focus of the poll (preelection […]