Polling response rates also affect polling results. As State Demographer in a rural state (South Dakota), changes in how the Census obtained and disseminated data made us increasingly dependent on the American Community Survey. It was definitely more current than the decennial census – but the small numbers of participants made it less reliable. Deborah Griffin, in “Measuring Survey Nonresponse by Race and Ethnicity” concluded: “The data suggest that special efforts are needed to address differential survey response rates – to increase the rates for areas with high concentrations of AIANs, Blacks and Hispanics . . . New methods to address low mail response must be developed.”
On February 27, 2019, PEW published “Response rates in telephone surveys have resumed their decline.” The critical part of the article is shown in the graph below – in 1997, the response rate was 36%, twenty years later it was 6%. Kind of makes polling more difficult – particularly when you project the decline down to 2020.
On 10/26, PEW published “What the 2020 electorate looks like by party, race and ethnicity, age, education and religion” and said, “Around a third of registered voters in the U.S. (34%) identify as independents, while 33% identify as Democrats and 29% identify as Republicans, according to a Center analysis of Americans’ partisan identification based on surveys of more than 12,000 registered voters in 2018 and 2019.” Contrast that with Gallup’s findings.
In 2013, the Research Council of Norway published, “Fewer Willing to Participate in Surveys.” The most relevant observation to political polling is “In general, NSD sees that young, single men living in urban areas are the least likely to respond, while older women are the most willing.”
Polling accuracy depends on random selection. As the proportion of respondents becomes smaller, the quality of randomness declines. Causation is not proven by correlation, it must be inferred. My inference is that the middle has stopped responding to polls – pollsters are getting responses from the same ideologically extreme friends who post political memes, and not from the center. When 94% of those surveyed do not respond, we’re looking at some extreme nonresponse bias.